1
|
Silva LM, Pereira L, Kaack L, Guan X, Pfaff J, Trabi CL, Jansen S. The potential link between gas diffusion and embolism spread in angiosperm xylem: Evidence from flow-centrifuge experiments and modelling. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39119783 DOI: 10.1111/pce.15084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/19/2024] [Accepted: 07/27/2024] [Indexed: 08/10/2024]
Abstract
Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. Here, we hypothesise that embolism spread involves gas diffusion in xylem, and is affected by time. We measured hydraulic conductivity (Kh) in flow-centrifuge experiments over 1 h at a given pressure and temperature for stem samples of three angiosperm species. Temporal changes in Kh at 5, 22, and 35°C, and at various pressures were compared to modelled gas concentration changes in a recently embolised vessel in the centre of a centrifuge sample. Temporal changes in Kh were logarithmic and species-specific. Maximum relative increases of Kh between 6% and 40% happened at 22°C for low centrifugal speed (<3250 RPM), while maximum decreases between 41% and 61% occurred at higher speeds. These reductions in Kh were experimentally shown to be associated with a temporal increase of embolism at the centre of centrifuge samples, which was likely associated with gas concentration increases in recently embolized vessels. Although embolism is mostly pressure-driven, our experimental and modelled data indicate that time, conduit characteristics, and temperature are involved due to their potential role in gas diffusion. Gas diffusion, however, does not seem to cover the entire process of embolism spread.
Collapse
Affiliation(s)
| | | | - Lucian Kaack
- Institute of Botany, Ulm University, Ulm, Germany
- Botanical Garden of Ulm University, Hans-Krebs-Weg, Ulm, Germany
| | - Xinyi Guan
- Institute of Botany, Ulm University, Ulm, Germany
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Jonas Pfaff
- Institute of Botany, Ulm University, Ulm, Germany
| | - Christophe L Trabi
- Institute of Botany, Ulm University, Ulm, Germany
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
| | | |
Collapse
|
2
|
Ingram S, Reischl B, Vesala T, Vehkamäki H. Ruptures of mixed lipid monolayers under tension and supercooling: implications for nanobubbles in plants. NANOSCALE ADVANCES 2024; 6:3775-3784. [PMID: 39050947 PMCID: PMC11265596 DOI: 10.1039/d4na00316k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/10/2024] [Indexed: 07/27/2024]
Abstract
Mixed phospholipid and glycolipid monolayers likely coat the surfaces of pressurised gas nanobubbles within the hydraulic systems of plants. The lipid coatings bond to water under negative pressure and are thus stretched out of equilibrium. In this work, we have used molecular dynamics simulations to produce trajectories of a biologically relevant mixed monolayer, pulled at mild negative pressures (-1.5 to -4.5 MPa). Pore formation within the monolayer is observed at both 270 and 310 K, and proceeds as an activated process once the lipid tails fully transition from the two dimensional liquid condensed to liquid expanded phase. Pressure:area isotherms showed reduced surface pressure under slight supercooling (T = 270 K) at all observed areas per lipid. Finally, Rayleigh-Plesset simulations were used to predict evolving nanobubble size using the calculated pressure:area isotherms as dynamic surface tensions. We confirm the existence of a second critical radius with respect to runaway growth, above the homogeneous cavitation radius.
Collapse
Affiliation(s)
- Stephen Ingram
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki P.O. Box 64 Helsinki FI-00014 Finland
| | - Bernhard Reischl
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki P.O. Box 64 Helsinki FI-00014 Finland
| | - Timo Vesala
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki P.O. Box 64 Helsinki FI-00014 Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki P.O. Box 27 Helsinki FI-00014 Finland
| | - Hanna Vehkamäki
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki P.O. Box 64 Helsinki FI-00014 Finland
| |
Collapse
|
3
|
Ma BL, Liao SH, Lv QZ, Huang X, Jiang ZM, Cai J. Seasonal plasticity of stem embolism resistance and its potential driving factors in six temperate woody species. PHYSIOLOGIA PLANTARUM 2024; 176:e14421. [PMID: 38956781 DOI: 10.1111/ppl.14421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 05/20/2024] [Accepted: 05/29/2024] [Indexed: 07/04/2024]
Abstract
The seasonal plasticity of resistance to xylem embolism has been demonstrated in leaves of some tree species, but is controversial in stems. In this study, we investigated the seasonality of stem xylem resistance to embolism in six temperate woody species (four deciduous and two evergreen tree species) that were grown at the same site. The xylem conduit anatomy, the concentrations, and ratios of the main cation in the xylem sap, as well as the content of nonstructural carbohydrates (including soluble sugars and starch) were measured in each species under each season to reveal the potential mechanisms of seasonal change in embolism resistance. The stem of all species showed increasing resistance to embolism as seasons progressed, with more vulnerable xylem in spring, but no significant adjustment in the other three seasons. The seasonal plasticity of stem embolism resistance was greater in deciduous species than in evergreen. On a seasonal scale, conduit diameter and conduit implosion resistance, the ratios of K+/Ca2+ and K+/Na+, and starch content were generally not correlated with embolism resistance, suggesting that these are probably not the main drivers of seasonal plasticity of stem embolism resistance. The seasonality of embolism resistance provides critical information for better understanding plant hydraulics in response to seasonal environments, especially under climate change.
Collapse
Affiliation(s)
- Bo-Long Ma
- College of Forestry, Northwest A&F University, Yangling, China
| | - Su-Hui Liao
- College of Forestry, Northwest A&F University, Yangling, China
| | - Qing-Zi Lv
- College of Forestry, Northwest A&F University, Yangling, China
| | - Xin Huang
- College of Forestry, Northwest A&F University, Yangling, China
| | - Zai-Min Jiang
- College of Life Sciences, Northwest A&F University, Yangling, China
| | - Jing Cai
- College of Forestry, Northwest A&F University, Yangling, China
- Qinling National Forest Ecosystem Research Station, Northwest A&F University, Yangling, China
| |
Collapse
|
4
|
Zhang Y, Pereira L, Kaack L, Liu J, Jansen S. Gold perfusion experiments support the multi-layered, mesoporous nature of intervessel pit membranes in angiosperm xylem. THE NEW PHYTOLOGIST 2024; 242:493-506. [PMID: 38404029 DOI: 10.1111/nph.19608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Fluid transport across intervessel pit membranes of angiosperm xylem plays a major role in plant transpiration, with transport resistance largely depending on pore constriction sizes. Traditionally, fluid particles traversing pit membranes are assumed to cross a single instead of multiple pore constrictions. We tested a multi-layered pit membrane model in xylem of eight angiosperm species by estimating the size frequency of pore constrictions in relation to pit membrane thickness and compared modelled data with perfusion characteristics of nanoscale gold particles based on transmission electron microscopy. The size frequency of modelled pore constrictions showed similar patterns to the measured number of perfused particle sizes inside pit membranes, although frequency values measured were 10-50 times below modelled data. Small particles enter pit membranes most easily, especially when injected in thin pit membranes. The trapping of gold particles by pore constrictions becomes more likely with increasing pore constriction number and pit membrane thickness. While quantitative differences between modelled and experimental data are due to various practical limitations, their qualitative agreement supports a multi-layered pit membrane model with multiple pore constrictions. Pore constrictions between 5 and 50 nm are realistic, and confirm the mesoporous nature of pit membranes.
Collapse
Affiliation(s)
- Ya Zhang
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Beijingzhong Road 2, Wuhu, 241000, China
| | - Luciano Pereira
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Lucian Kaack
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Jiabao Liu
- College of Ecology and Environment, Anhui Normal University, Beijingzhong Road 2, Wuhu, 241000, China
| | - Steven Jansen
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| |
Collapse
|
5
|
Beckett HAA, Bryant C, Neeman T, Mencuccini M, Ball MC. Plasticity in branch water relations and stem hydraulic vulnerability enhances hydraulic safety in mangroves growing along a salinity gradient. PLANT, CELL & ENVIRONMENT 2024; 47:854-870. [PMID: 37975319 DOI: 10.1111/pce.14764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Coping with water stress depends on maintaining cellular function and hydraulic conductance. Yet measurements of vulnerability to drought and salinity do not often focus on capacitance in branch organs that buffer hydraulic function during water stress. The relationships between branch water relations, stem hydraulic vulnerability and stem anatomy were investigated in two co-occurring mangroves Aegiceras corniculatum and Rhizophora stylosa growing at low and high salinity. The dynamics of branch water release acted to conserve water content in the stem at the expense of the foliage during extended drying. Hydraulic redistribution from the foliage to the stem increased stem relative water content by up to 21%. The water potentials at which 12% and 50% loss of stem hydraulic conductivity occurred decreased by ~1.7 MPa in both species between low and high salinity sites. These coordinated tissue adjustments increased hydraulic safety despite declining turgor safety margins at higher salinity sites. Our results highlight the complex interplay of plasticity in organ-level water relations with hydraulic vulnerability in the maintenance of stem hydraulic function in mangroves distributed along salinity gradients. These results emphasise the importance of combining water relations and hydraulic vulnerability parameters to understand vulnerability to water stress across the whole plant.
Collapse
Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Callum Bryant
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Teresa Neeman
- Biological Data Science Institute, Australian National University, Canberra, Australia
| | - Maurizio Mencuccini
- Ecological and Forestry Applications Research Centre (CREAF), Barcelona, Bellaterra, Spain
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| |
Collapse
|
6
|
Liu YY, Chao L, Li ZG, Ma L, Hu BQ, Zhu SD, Cao KF. Water storage capacity is inversely associated with xylem embolism resistance in tropical karst tree species. TREE PHYSIOLOGY 2024; 44:tpae017. [PMID: 38281245 DOI: 10.1093/treephys/tpae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
Tropical karst habitats are characterized by limited and patchy soil, large rocky outcrops and porous substrates, resulting in high habitat heterogeneity and soil moisture fluctuations. Xylem hydraulic efficiency and safety can determine the drought adaptation and spatial distribution of woody plants growing in karst environments. In this study, we measured sapwood-specific hydraulic conductivity (Ks), vulnerability to embolism, wood density, saturated water content, and vessel and pit anatomical characteristics in the branch stems of 12 evergreen tree species in a tropical karst seasonal rainforest in southwestern China. We aimed to characterize the effects of structural characteristics on hydraulic efficiency and safety. Our results showed that there was no significant correlation between Ks and hydraulic safety across the tropical karst woody species. Ks was correlated with hydraulic vessel diameter (r = 0.80, P < 0.05) and vessel density (r = -0.60, P < 0.05), while the stem water potential at 50 and 88% loss of hydraulic conductivity (P50 and P88) were both significantly correlated with wood density (P < 0.05) and saturated water content (P = 0.052 and P < 0.05, respectively). High stem water storage capacity was associated with low cavitation resistance possibly because of its buffering the moisture fluctuations in karst environments. However, both Ks and P50/P88 were decoupled from the anatomical traits of pit and pit membranes. This may explain the lack of tradeoff between hydraulic safety and efficiency in tropical karst evergreen tree species. Our results suggest that diverse hydraulic trait combination may facilitate species coexistence in karst environments with high spatial heterogeneity.
Collapse
Affiliation(s)
- Yan-Yan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Nanning Normal University, Nanning 530001, China
| | - Lin Chao
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Nanning Normal University, Nanning 530001, China
| | - Zhong-Guo Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
- Experimental Center of Tropical Forestry, Chinese Academy of Forestry, Pingxiang 532600, Guangxi, China
| | - Lin Ma
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Nanning Normal University, Nanning 530001, China
| | - Bao-Qing Hu
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Nanning Normal University, Nanning 530001, China
| | - Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, Guangxi, China
| |
Collapse
|
7
|
Ávila-Lovera E, Haro R, Choudhary M, Acosta-Rangel A, Pratt RB, Santiago LS. The benefits of woody plant stem photosynthesis extend to hydraulic function and drought survival in Parkinsonia florida. TREE PHYSIOLOGY 2024; 44:tpae013. [PMID: 38284819 PMCID: PMC10918054 DOI: 10.1093/treephys/tpae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 01/16/2024] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
As climate change exacerbates drought stress in many parts of the world, understanding plant physiological mechanisms for drought survival is critical to predicting ecosystem responses. Stem net photosynthesis, which is common in arid environments, may be a drought survival trait, but whether the additional carbon fixed by stems contributes to plant hydraulic function and drought survival in arid land plants is untested. We conducted a stem light-exclusion experiment on saplings of a widespread North American desert tree species, Parkinsonia florida L., and after shading acclimation, we then subjected half of the plants to a drought treatment to test the interaction between light exclusion and water limitation on growth, leaf and stem photosynthetic gas exchange, xylem embolism assessed with micro-computed tomography and gravimetric techniques, and survival. Growth, stem photosynthetic gas exchange, hydraulic function and survival all showed expected reductions in response to light exclusion. However, stem photosynthesis mitigated the drought-induced reductions in gas exchange, xylem embolism (percent loss of conductivity, PLC) and mortality. The highest mortality was in the combined light exclusion and drought treatment, and was related to stem PLC and native sapwood-specific hydraulic conductivity. This research highlights the integration of carbon economy and water transport. Our results show that additional carbon income by photosynthetic stems has an important role in the growth and survival of a widespread desert tree species during drought. This shift in function under conditions of increasing stress underscores the importance of considering stem photosynthesis for predicting drought-induced mortality not only for the additional supply of carbon, but also for its extended benefits for hydraulic function.
Collapse
Affiliation(s)
- Eleinis Ávila-Lovera
- School of Biological Sciences, The University of Utah, 257 S 1400 E, Salt Lake City, UT 84112, USA
- Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA 92521, USA
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama, Republic of Panama
| | - Roxana Haro
- Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA 92521, USA
| | - Manika Choudhary
- Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA 92521, USA
| | - Aleyda Acosta-Rangel
- Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA 92521, USA
| | - R Brandon Pratt
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA 93311, USA
| | - Louis S Santiago
- Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA 92521, USA
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama, Republic of Panama
| |
Collapse
|
8
|
Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
Collapse
Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
| |
Collapse
|
9
|
Losso A, Gauthey A, Choat B, Mayr S. Seasonal variation in the xylem sap composition of six Australian trees and shrubs. AOB PLANTS 2023; 15:plad064. [PMID: 37899974 PMCID: PMC10601387 DOI: 10.1093/aobpla/plad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023]
Abstract
In recent years, xylem sap composition has been shown to affect xylem hydraulics. However, information on how much xylem sap composition can vary across seasons and specifically under drought stress is still limited. We measured xylem sap chemical composition ([Ca2+], [K+], [Na+], electrical conductivity EC and pH) and surface tension (γ) of six Australian angiosperm trees and shrubs over 1 year, which comprised of exceptional dry and wet periods. Percentage losses of hydraulic conductivity and predawn leaf water potential were also monitored. In all species, measured parameters changed considerably over the annual time course. Ions and pH tended to decrease during winter months whereas γ showed a slight increase. No clear correlation was found between sap and hydraulic parameters, except for pH that was higher when plants suffered higher drought stress levels. Results indicate xylem sap composition to be complex and dynamic, where most variation in its composition seems to be dictated by season, even under severe dry conditions. However, pH might play a role as signals of drought stress.
Collapse
Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| |
Collapse
|
10
|
Ingram S, Jansen S, Schenk HJ. Lipid-Coated Nanobubbles in Plants. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1776. [PMID: 37299679 PMCID: PMC10254470 DOI: 10.3390/nano13111776] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/12/2023]
Abstract
One of the more surprising occurrences of bulk nanobubbles is in the sap inside the vascular transport system of flowering plants, the xylem. In plants, nanobubbles are subjected to negative pressure in the water and to large pressure fluctuations, sometimes encompassing pressure changes of several MPa over the course of a single day, as well as wide temperature fluctuations. Here, we review the evidence for nanobubbles in plants and for polar lipids that coat them, allowing nanobubbles to persist in this dynamic environment. The review addresses how the dynamic surface tension of polar lipid monolayers allows nanobubbles to avoid dissolution or unstable expansion under negative liquid pressure. In addition, we discuss theoretical considerations about the formation of lipid-coated nanobubbles in plants from gas-filled spaces in the xylem and the role of mesoporous fibrous pit membranes between xylem conduits in creating the bubbles, driven by the pressure gradient between the gas and liquid phase. We discuss the role of surface charges in preventing nanobubble coalescence, and conclude by addressing a number of open questions about nanobubbles in plants.
Collapse
Affiliation(s)
- Stephen Ingram
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, 00560 Helsinki, Finland
| | - Steven Jansen
- Institute of Botany, Ulm University, 89081 Ulm, Germany
| | - H. Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831-3599, USA
| |
Collapse
|
11
|
Isasa E, Link RM, Jansen S, Tezeh FR, Kaack L, Sarmento Cabral J, Schuldt B. Addressing controversies in the xylem embolism resistance-vessel diameter relationship. THE NEW PHYTOLOGIST 2023; 238:283-296. [PMID: 36636783 DOI: 10.1111/nph.18731] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Although xylem embolism is a key process during drought-induced tree mortality, its relationship to wood anatomy remains debated. While the functional link between bordered pits and embolism resistance is known, there is no direct, mechanistic explanation for the traditional assumption that wider vessels are more vulnerable than narrow ones. We used data from 20 temperate broad-leaved tree species to study the inter- and intraspecific relationship of water potential at 50% loss of conductivity (P50 ) with hydraulically weighted vessel diameter (Dh ) and tested its link to pit membrane thickness (TPM ) and specific conductivity (Ks ) on species level. Embolism-resistant species had thick pit membranes and narrow vessels. While Dh was weakly associated with TPM , the P50 -Dh relationship remained highly significant after accounting for TPM . The interspecific pattern between P50 and Dh was mirrored by a link between P50 and Ks , but there was no evidence for an intraspecific relationship. Our results provide robust evidence for an interspecific P50 -Dh relationship across our species. As a potential cause for the inconsistencies in published P50 -Dh relationships, our analysis suggests differences in the range of trait values covered, and the level of data aggregation (species, tree or sample level) studied.
Collapse
Affiliation(s)
- Emilie Isasa
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
| | - Roman Mathias Link
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Pienner Str. 7, 01737, Tharandt, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Fon Robinson Tezeh
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Juliano Sarmento Cabral
- Ecosystem Modeling Group, Center for Computational and Theoretical Biology, University of Würzburg, Klara-Oppenheimer-Weg 32, 97074, Würzburg, Germany
- Biodiversity Modelling and Environmental Change, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Bernhard Schuldt
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Pienner Str. 7, 01737, Tharandt, Germany
| |
Collapse
|
12
|
Eyegheleme NL, Umashankar V, Miller DN, Kota AK, Boreyko JB. Oil-Water Separation using Synthetic Trees. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2520-2528. [PMID: 36749622 DOI: 10.1021/acs.langmuir.2c02713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Existing oil-water filtration techniques require gravity or a pump as the driving force for separation. Here, we demonstrate transpiration-powered oil-water filtration using a synthetic tree, which operates pumplessly and against gravity. From top to bottom, our synthetic tree was composed of: a nanoporous "leaf" to generate suction via evaporation, a vertical array of glass tubes serving as the tree's xylem conduits, and filters attached to the tube inlets to act as the oil-excluding roots. When placing the tree in an oil emulsion bath, filtrate samples were measured to be 97-98% pure water using gravimetry and refractometry. The spontaneous oil-water separation offered by synthetic trees could be useful for applications such as oil spill cleanup, wastewater purification, and oil extraction.
Collapse
Affiliation(s)
- Ndidi L Eyegheleme
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Viverjita Umashankar
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Danielle N Miller
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Arun K Kota
- Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jonathan B Boreyko
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| |
Collapse
|
13
|
Guo L, Liu Y, Liu L, Yin P, Liu C, Li J. Study of the mechanism of embolism removal in xylem vessels by using microfluidic devices. LAB ON A CHIP 2023; 23:737-747. [PMID: 36594973 DOI: 10.1039/d2lc00945e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Determining the mechanism that effects embolism repair in the xylem vessels of plants is of great significance in predicting plant distribution and the screening of drought-resistant plants. However, the mechanism of perforation plates of xylem vessels in the acceleration of embolism repair is still not clear by using conventional methods of anatomy and visualization technology. Microfluidic devices have shown their ability to simulate physiological environments and conduct quantitative experiments. This work proposes a biomimetic microfluidic device to study the mechanism of perforation plates of xylem vessels in the acceleration of embolism repair. The results proffered that the perforation plates increase the rate of embolism removal by increasing the pressure differential through the vessel, and the rate of embolism removal is related to the structural parameters of the perforation plate. A combination of the perforation size, the vessel diameter and the perforation plate angle can be optimised to generate higher pressure differentials, which can accelerate the process of embolism repair. This work provides a new method for studying the mechanism of microstructures of natural plants. Furthermore, the mechanism that perforation plates accelerate embolism repair was applied to an electrochemical flow sensor for online determination of heavy metal ions. Test results of this application indicate that the mechanism can be applied in the engineering field to solve the problems of reduced sensitivity of devices, inaccuracy of analysis results and poor reaction performance caused by bubbles that are generated or introduced easily in microdevices, which paves the way for applying the theory to engineering.
Collapse
Affiliation(s)
- Lihua Guo
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Yuanchang Liu
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Li Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Penghe Yin
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Chong Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Jingmin Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| |
Collapse
|
14
|
Lens F, Gleason SM, Bortolami G, Brodersen C, Delzon S, Jansen S. Functional xylem characteristics associated with drought-induced embolism in angiosperms. THE NEW PHYTOLOGIST 2022; 236:2019-2036. [PMID: 36039697 DOI: 10.1111/nph.18447] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Hydraulic failure resulting from drought-induced embolism in the xylem of plants is a key determinant of reduced productivity and mortality. Methods to assess this vulnerability are difficult to achieve at scale, leading to alternative metrics and correlations with more easily measured traits. These efforts have led to the longstanding and pervasive assumed mechanistic link between vessel diameter and vulnerability in angiosperms. However, there are at least two problems with this assumption that requires critical re-evaluation: (1) our current understanding of drought-induced embolism does not provide a mechanistic explanation why increased vessel width should lead to greater vulnerability, and (2) the most recent advancements in nanoscale embolism processes suggest that vessel diameter is not a direct driver. Here, we review data from physiological and comparative wood anatomy studies, highlighting the potential anatomical and physicochemical drivers of embolism formation and spread. We then put forward key knowledge gaps, emphasising what is known, unknown and speculation. A meaningful evaluation of the diameter-vulnerability link will require a better mechanistic understanding of the biophysical processes at the nanoscale level that determine embolism formation and spread, which will in turn lead to more accurate predictions of how water transport in plants is affected by drought.
Collapse
Affiliation(s)
- Frederic Lens
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
- Leiden University, Institute of Biology Leiden, Plant Sciences, Sylviusweg 72, 2333 BE, Leiden, the Netherlands
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
| | - Giovanni Bortolami
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, 06511, USA
| | - Sylvain Delzon
- University of Bordeaux, INRAE, BIOGECO, 33615, Pessac, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| |
Collapse
|
15
|
Guan X, Schenk HJ, Roth MR, Welti R, Werner J, Kaack L, Trabi CL, Jansen S. Nanoparticles are linked to polar lipids in xylem sap of temperate angiosperm species. TREE PHYSIOLOGY 2022; 42:2003-2019. [PMID: 35552762 DOI: 10.1093/treephys/tpac054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
In previous research, xylem sap of angiosperms has been found to include low concentrations of nanoparticles and polar lipids. A major goal of this study was to test predictions arising from the hypothesis that the nanoparticles consist largely of polar lipids from the original cell content of vessel elements. These predictions included that polar lipid and nanoparticle concentrations would be correlated, that they both do not pass through pit membranes and that they do not vary seasonally because they originate from living vessel element cells. We collected xylem sap of six temperate angiosperm species over the whole year to consider seasonal variation. Concentrations of nanoparticles and lipids in xylem sap and contamination control samples were measured with a NanoSight device and mass spectrometry. We found that the concentration of nanoparticles and polar lipids was (i) diluted when an increasing amount of sap was extracted, (ii) significantly correlated to each other for three species, (iii) affected by vessel anatomy, (iv) very low and largely different in chemical composition from contamination controls and (v) hardly variable among seasons. Moreover, there was a minor freezing-thawing effect with respect to nanoparticle amount and size. Xylem sap lipids included polar galactolipids and phospholipids in all species and neutral triacylglycerols in two species. These findings support the predictions and, by implication, the underlying hypothesis that nanoparticles in xylem sap consist of polar lipids from the original cell content of living vessel element cells. Further research is needed to examine the formation and stability of nanoparticles concerning lipid composition and multiphase interactions among gas, liquid and solid phases in xylem conduits of living plants.
Collapse
Affiliation(s)
- Xinyi Guan
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA 92831, USA
| | - Mary R Roth
- Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ruth Welti
- Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Julia Werner
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Christophe L Trabi
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| |
Collapse
|
16
|
Levionnois S, Kaack L, Heuret P, Abel N, Ziegler C, Coste S, Stahl C, Jansen S. Pit characters determine drought-induced embolism resistance of leaf xylem across 18 Neotropical tree species. PLANT PHYSIOLOGY 2022; 190:371-386. [PMID: 35567500 PMCID: PMC9434246 DOI: 10.1093/plphys/kiac223] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/19/2022] [Indexed: 05/16/2023]
Abstract
Embolism spreading in xylem is an important component of plant drought resistance. Since embolism resistance has been shown to be mechanistically linked to pit membrane characters in stem xylem, we speculate that similar mechanisms account for leaf xylem. We conducted transmission electron microscopy to investigate pit membrane characters in leaf xylem across 18 Neotropical tree species. We also conducted gold perfusion and polar lipid detection experiments on three species covering the full range of leaf embolism resistance. We then related these observations to previously published data on embolism resistance of leaf xylem. We also incorporated previously published data on stem embolism resistance and stem xylem pit membranes to investigate the link between vulnerability segmentation (i.e. difference in embolism resistance) and leaf-stem anatomical variation. Maximum pit membrane thickness (Tpm,max) and the pit membrane thickness-to-diameter ratio (Tpm,max/Dpm) were predictive of leaf embolism resistance, especially when vestured pits were taken into account. Variation in Tpm,max/Dpm was the only trait predictive of vulnerability segmentation between leaves and stems. Gold particles of 5- and 10-nm infiltrated pit membranes in three species, while the entry of 50-nm particles was blocked. Moreover, polar lipids were associated with inner conduit walls and pits. Our results suggest that mechanisms related to embolism spreading are determined by Tpm, pore constrictions (i.e. the narrowest bottlenecks along pore pathways), and lipid surfactants, which are largely similar between leaf and stem xylem and between temperate and tropical trees. However, our mechanistic understanding of embolism propagation and the functional relevance of Tpm,max/Dpm remains elusive.
Collapse
Affiliation(s)
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Ulm D-89081, Germany
| | | | - Nina Abel
- Institute of Systematic Botany and Ecology, Ulm University, Ulm D-89081, Germany
| | - Camille Ziegler
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
- Université de Lorraine, AgroParisTech, INRAE, UMR SILVA, Nancy 54000, France
| | - Sabrina Coste
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
| | - Clément Stahl
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
| | | |
Collapse
|
17
|
De La Fuente L, Merfa MV, Cobine PA, Coleman JJ. Pathogen Adaptation to the Xylem Environment. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:163-186. [PMID: 35472277 DOI: 10.1146/annurev-phyto-021021-041716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A group of aggressive pathogens have evolved to colonize the plant xylem. In this vascular tissue, where water and nutrients are transported from the roots to the rest of the plant, pathogens must be able to thrive under acropetal xylem sap flow and scarcity of nutrients while having direct contact only with predominantly dead cells. Nevertheless, a few bacteria have adapted to exclusively live in the xylem, and various pathogens may colonize other plant niches without causing symptoms unless they reach the xylem. Once established, the pathogens modulate its physicochemical conditions to enhance their growth and virulence. Adaptation to the restrictive lifestyle of the xylem leads to genome reduction in xylem-restricted bacteria, as they have a higher proportion of pseudogenes in their genome. The basis of xylem adaptation is not completely understood; therefore, a need still exists for model systems to advance the knowledge on this topic.
Collapse
Affiliation(s)
- Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Jeffrey J Coleman
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| |
Collapse
|
18
|
Olson ME. Linking xylem structure and function: the comparative method in from the cold. THE NEW PHYTOLOGIST 2022; 235:815-820. [PMID: 35770485 PMCID: PMC9328200 DOI: 10.1111/nph.18179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This article is a Commentary on Savage et al. (2022), 235: 953–964.
Collapse
Affiliation(s)
- Mark E. Olson
- Instituto de BiologíaUniversidad Nacional Autónoma de MéxicoTercer Circuito sn de Ciudad UniversitariaCiudad de México04510Mexico
| |
Collapse
|
19
|
Li S, Li X, Wang J, Chen Z, Lu S, Wan X, Sun H, Wang L, Delzon S, Cochard H, Jiang X, Shu J, Zheng J, Yin Y. Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L. TREE PHYSIOLOGY 2022; 42:1216-1227. [PMID: 34962276 DOI: 10.1093/treephys/tpab174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Investigating the responses of plant anatomical traits of trees to drought-rewatering cycles helps us to understand their responses to climate change; however, such work has not been adequately reported. In this study, Ginkgo biloba L. saplings were subjected to moderate, severe, extreme and lethal drought conditions by withholding water according to the percentage loss of hydraulic conductivity (PLC) and rewatering on a regular basis. Samples of phloem, cambium and xylem were collected to quantify their cellular properties including cambium and phloem cell vitality, xylem growth ring width, pit aspiration rates and pit membrane thickness using light microscopy and transmission microscopy. The results showed that the mortality rate of G. biloba saplings reached 90% at approximately P88 (xylem water potential inducing 88% loss of hydraulic conductivity). The onset of cambium and phloem cell mortality might be in accordance with that of xylem embolism. Close negative correlations between xylem water potential and PLC and between xylem water potential and cambium and phloem mortality suggested that xylem hydraulic traits are coupled with anatomical traits under declining xylem water potential. Cambium and phloem cell vitality as well as xylem growth ring width decreased significantly with increasing drought conditions. However, xylem pit membrane thickness, cambial zone width and cambial cell geometry were not affected by the drought-rewatering cycles. The tracheid radial diameter, intertracheid cell wall thickness and tracheid density decreased significantly during both drought conditions and rewatering conditions. In addition to hydraulic traits, cambium and phloem cell vitality can be used as anatomical traits to evaluate the mortality of G. biloba under drought. Future work is proposed to observe the dynamics of pit aspiration rates under drought-rewatering cycles in situ to deepen our understanding of the essential role of bordered pits in the 'air-seeding' mechanism.
Collapse
Affiliation(s)
- Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P.R. China
| | - Xin Li
- College of Forestry, Beijing Forestry University, Beijing 100083, P.R. China
| | - Jie Wang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Zhicheng Chen
- Key laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Sen Lu
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P.R. China
| | - Xianchong Wan
- Key laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Hongyan Sun
- Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
- Beijing Key Lab of Greening Plants Breeding, Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
| | - Li Wang
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, P.R. China
| | - Sylvain Delzon
- INRAE, BIOGECO, University of Bordeaux, 33615 Pessac, France
| | - Herve Cochard
- INRAE, PIAF, Université Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Xiaomei Jiang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Jianhua Shu
- Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
- Beijing Key Lab of Greening Plants Breeding, Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
| | - Jingming Zheng
- College of Forestry, Beijing Forestry University, Beijing 100083, P.R. China
| | - Yafang Yin
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
| |
Collapse
|
20
|
Wu X, Yuan F, Wang X, Zhu S, Pei ZM. Evolution of osmosensing OSCA1 Ca 2+ channel family coincident with plant transition from water to land. THE PLANT GENOME 2022; 15:e20198. [PMID: 35502648 DOI: 10.1002/tpg2.20198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Water is crucial to plant growth, development, and environmental adaptation. Water stress triggers cytosolic Ca2+ ([Ca2+ ]i ) increases, and the osmosensor OSCA1 (REDUCED-HYPEROSMOLALITY-INDUCED-[Ca2+ ]i -INCREASE 1), a member of the OSCA family, perceives the initial water stress and governs its downstream responses. OSCA homologs exist in eukaryotes and largely radiate in higher plants. However, it is enigmatic whether the OSCA family is crucial for plant evolution from aqueous to terrestrial environments and for the subsequent adaptation on land. Here, we carried out the first phylogenetic and molecular evolutionary analyses of the OSCA family. The family originated and diversified during the early evolution of protists, and three more lineages were established (a) in plants, (b) in fungi, and (c) in a complex clade of several major eukaryotic lineages. The chlorophyte algal cluster is directly basal to streptophyte-specific Clades 1-3, consistent with plant transition from water to land. The Clades 1-3 present different gene expansion pattern and together with previous functional analysis of OSCAs reveal that they probably have evolved diverse functions in respond to various mechanical stresses during the independent evolution of land plant clades. Moreover, variable selection pressures on different land plant lineages were explored. OSCAs in early land plants (mosses and lycophytes) were under decelerated evolution, whereas OSCAs in seed plants showed accelerated evolution. Together, we hypothesize OSCAs have evolved to sense water stress in the ancestor of euphyllophytes, which occupies typical leaves, typical roots, and phloem tissues, all of which require osmosensors to maintain water balance and food conduction through plant bodies.
Collapse
Affiliation(s)
- Xiaomei Wu
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
- Dep. of Biology, Duke Univ., Durham, NC, 27708, USA
| | - Fang Yuan
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
- Dep. of Biology, Duke Univ., Durham, NC, 27708, USA
| | - Xuewen Wang
- Center for Human Identification, Univ. of North Texas Health Science Center, Fort Worth, TX, 76107, USA
| | - Shan Zhu
- College of Life and Environmental Sciences, Hangzhou Normal Univ., Hangzhou, 311121, China
| | | |
Collapse
|
21
|
Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
Collapse
Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
| |
Collapse
|
22
|
Guo L, Liu Y, Ran P, Wang G, Shan J, Li X, Liu C, Li J. A bioinspired bubble removal method in microchannels based on angiosperm xylem embolism repair. MICROSYSTEMS & NANOENGINEERING 2022; 8:34. [PMID: 35402001 PMCID: PMC8940964 DOI: 10.1038/s41378-022-00367-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/23/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
It is difficult to remove and eliminate bubbles in microchannels in many devices used in various biomedical fields, such as those needed for microfluidic immunoassays, point-of-care testing, and cell biology evaluations. Accumulated bubbles are associated with a number of negative outcomes, including a decrease in device sensitivity, inaccuracy of analysis results, and even functional failure. Xylem conduits of angiosperm have the ability to remove bubbles in obstructed conduits. Inspired by such an embolism repair mechanism, this paper proposes a bioinspired bubble removal method, which exhibits a prominent ability to dissolve bubbles continuously within a large range of flow rates (2 µL/min-850 µL/min) while retaining the stability and continuity of the flow without auxiliary equipment. Such a method also shows significant bubble removal stability in dealing with Newtonian liquids and non-Newtonian fluids, especially with high viscosity (6.76 Pa s) and low velocity (152 nL/min). Such advantages associated with the proposed bioinspired method reveal promising application prospects in macro/microfluidic fields ranging from 3D printing, implantable devices, virus detection, and biomedical fluid processing to microscale reactor operation and beyond.
Collapse
Affiliation(s)
- Lihua Guo
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Yuanchang Liu
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
| | - Penghui Ran
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Gang Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Jie Shan
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Xudong Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Chong Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Jingmin Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| |
Collapse
|
23
|
Kawai K, Minagi K, Nakamura T, Saiki ST, Yazaki K, Ishida A. Parenchyma underlies the interspecific variation of xylem hydraulics and carbon storage across 15 woody species on a subtropical island in Japan. TREE PHYSIOLOGY 2022; 42:337-350. [PMID: 34328187 DOI: 10.1093/treephys/tpab100] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
Parenchyma is an important component of the secondary xylem. It has multiple functions and its fraction is known to vary substantially across angiosperm species. However, the physiological significance of this variation is not yet fully understood. Here, we examined how different types of parenchyma (ray parenchyma [RP], axial parenchyma [AP] and AP in direct contact with vessels [APV]) are coordinated with three essential xylem functions: water conduction, storage of non-structural carbohydrate (NSC) and mechanical support. Using branch sapwood of 15 co-occurring drought-adapted woody species from the subtropical Bonin Islands, Japan, we quantified 10 xylem anatomical traits and examined their linkages to hydraulic properties, storage of soluble sugars and starch and sapwood density. The fractions of APV and AP in the xylem transverse sections were positively correlated with the percentage loss of conductivity in the native condition, whereas that of RP was negatively correlated with the maximum conductivity across species. Axial and ray parenchyma fractions were positively associated with concentrations of starch and NSC. The fraction of parenchyma was independent of sapwood density, regardless of parenchyma type. We also identified a negative relationship between hydraulic conductivity and NSC storage and sapwood density, mirroring the negative relationship between the fractions of parenchyma and vessels. These results suggest that parenchyma fraction underlies species variation in xylem hydraulic and carbon use strategies, wherein xylem with a high fraction of AP may adopt an embolism repair strategy through an increased starch storage with low cavitation resistance.
Collapse
Affiliation(s)
- Kiyosada Kawai
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
- Forestry Division, Japan International Research Center for Agricultural Sciences, Ohwashi 1-1 Tsukuba, Ibaraki 305-8686, Japan
| | - Kanji Minagi
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
| | - Tomomi Nakamura
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
| | - Shin-Taro Saiki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
| | - Kenichi Yazaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, Hitsujigaoka 7, Sapporo, Hokkaido 062-8516, Japan
| | - Atsushi Ishida
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
| |
Collapse
|
24
|
Campos J, Bodelon L, Verdeguer M, Baur P. Mechanistic Aspects and Effects of Selected Tank-Mix Partners on Herbicidal Activity of a Novel Fatty Acid Ester. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030279. [PMID: 35161260 PMCID: PMC8839195 DOI: 10.3390/plants11030279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 05/14/2023]
Abstract
Only a limited number of contact herbicides exist in agricultural production. While systemic herbicides are more efficient also at suboptimum spray coverage with long-lasting weed control, contact herbicides provide several advantages. There is no translocation to fruits or roots of plantation and other crop, low risk for resistance development, and minor risk for spray-drift damage. Besides, synthetic products that often have toxicological or residues issues, natural fatty acids, particularly pelargonic acid (PA), have contact activity and are safer for home and garden use. We recently described a methyl capped polyethylene glycol ester of pelargonic acid (PA-MPEG) that acts independent of acid formation. Both, PA-MPEG and PA are applied at high rates per hectare to achieve excellent weed control. Here, we report about potential additives to increase PA-MPEG efficacy. The herbicidal active, 1-decanol, and the non-phytotoxic alkylated seed oil-based adjuvant, HastenTM, improved performance and outperformed a commercial PA herbicide. Both, PA-MPEG and PA appear to mainly act by the disintegration of bio-membranes besides having effects on transpiration. The main suggested effect is desiccation due to cutting the water continuum at the site of evaporation in the intercellular spaces. The synergistic action of the adjuvant HastenTM and its practical uses are also discussed.
Collapse
Affiliation(s)
- Javier Campos
- Global Innovation & Technology, Clariant, 65926 Frankfurt am Main, Germany;
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, 46022 Valencia, Spain;
- Correspondence: ; Tel.: +49-15735528819
| | - Luciana Bodelon
- Global Innovation & Technology, Clariant, 65926 Frankfurt am Main, Germany;
| | - Mercedes Verdeguer
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, 46022 Valencia, Spain;
| | - Peter Baur
- CropPromotion, 86938 Schondorf am Ammersee, Germany;
| |
Collapse
|
25
|
Ingram S, Salmon Y, Lintunen A, Hölttä T, Vesala T, Vehkamäki H. Dynamic Surface Tension Enhances the Stability of Nanobubbles in Xylem Sap. FRONTIERS IN PLANT SCIENCE 2021; 12:732701. [PMID: 34975934 PMCID: PMC8716698 DOI: 10.3389/fpls.2021.732701] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/29/2021] [Indexed: 05/28/2023]
Abstract
Air seeded nanobubbles have recently been observed within tree sap under negative pressure. They are stabilized by an as yet unidentified process, although some embolize their vessels in extreme circumstances. Current literature suggests that a varying surface tension helps bubbles survive, but few direct measurements of this quantity have been made. Here, we present calculations of dynamic surface tension for two biologically relevant lipids using molecular dynamics simulations. We find that glycolipid monolayers resist expansion proportionally to the rate of expansion. Their surface tension increases with the tension applied, in a similar way to the viscosity of a non-Newtonian fluid. In contrast, a prototypical phospholipid was equally resistant to all applied tensions, suggesting that the fate of a given nanobubble is dependent on its surface composition. By incorporating our results into a Classical Nucleation Theory (CNT) framework, we predict nanobubble stability with respect to embolism. We find that the metastable radius of glycolipid coated nanobubbles is approximately 35 nm, and that embolism is in this case unlikely when the external pressure is less negative than -1.5 MPa.
Collapse
Affiliation(s)
- Stephen Ingram
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Timo Vesala
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
- Laboratory of Ecosystem-Atmospheric Interactions of Forest – Mire Complexes, Yugra State University, Khanty-Mansiysk, Russia
| | - Hanna Vehkamäki
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| |
Collapse
|
26
|
Lemaire C, Quilichini Y, Brunel-Michac N, Santini J, Berti L, Cartailler J, Conchon P, Badel É, Herbette S. Plasticity of the xylem vulnerability to embolism in Populus tremula x alba relies on pit quantity properties rather than on pit structure. TREE PHYSIOLOGY 2021; 41:1384-1399. [PMID: 33554260 DOI: 10.1093/treephys/tpab018] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Knowledge on variations of drought resistance traits are needed to predict the potential of trees to acclimate to coming severe drought events. Xylem vulnerability to embolism is a key parameter related to such droughts, and its phenotypic variability relies mainly on environmental plasticity. We investigated the structural determinants controlling the plasticity of vulnerability to embolism, focusing on the key elements involved in the air bubble entry in vessels, especially the intervessel pits. Poplar saplings (Populus tremula x alba (Aiton) Sm., 1804) grown in contrasted water availability or light exposure exhibited differences in the vulnerability to embolism (P50) in a range of 0.76 MPa. We then characterized the structural changes in features related to pit quantity and pit structure, from the pit ultrastructure to the organization of xylem vessels, using different microscopy techniques (transmission electron microscopy, scanning electron microscopy, light microscopy). A multispectral combination of X-ray microtomography and light microscopy analysis allowed measuring the vulnerability of each single vessel and testing some of the relationships between structural traits and vulnerability to embolism inside the xylem. The pit ultrastructure did not change, whereas the vessel dimensions increased with the vulnerability to embolism and the grouping index and fraction of intervessel cell wall both decreased with the vulnerability to embolism. These findings hold when comparing between trees or between the vessels inside the xylem of an individual tree. These results evidenced that plasticity of vulnerability to embolism in hybrid poplar occurs through changes in the pit quantity properties such as pit area and vessel grouping rather than changes on the pit structure.
Collapse
Affiliation(s)
- Cédric Lemaire
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Yann Quilichini
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | | | - Jérémie Santini
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | - Liliane Berti
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | - Julien Cartailler
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Pierre Conchon
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Éric Badel
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Stéphane Herbette
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| |
Collapse
|
27
|
Mrad A, Johnson DM, Love DM, Domec JC. The roles of conduit redundancy and connectivity in xylem hydraulic functions. THE NEW PHYTOLOGIST 2021; 231:996-1007. [PMID: 33908055 DOI: 10.1111/nph.17429] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity has been elusive. The objective here is to establish an analytical linkage between conduit connectivity and grouping and tissue-scale hydraulics. It is hypothesized that an increase in conduit connectivity brings improved resistance to embolism spread due to increased hydraulic pathway redundancy. However, an increase in conduit connectivity could also reduce resistance due to increased speed of embolism spread with respect to pressure. We elaborate on this trade-off using graph theory, percolation theory and computational modeling of xylem. The results are validated using anatomical measurements of Acer branch xylem. Considering only species with vessels, increases in connectivity improve resistance to embolism spread without negatively affecting hydraulic conductivity. The often measured grouping index fails to capture the totality of the effect of conduit connectivity on xylem hydraulics. Variations in xylem network characteristics, such as conduit connectivity, might explain why hypothesized trends among woody species, such as the 'safety-efficiency' trade-off hypothesis, are weaker than expected.
Collapse
Affiliation(s)
- Assaad Mrad
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, 92697, USA
- Department of Engineering, Wake Forest University, Winston-Salem, NC, 27101, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - David M Love
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, Gradignan Cedex, 33175, France
| |
Collapse
|
28
|
Thonglim A, Delzon S, Larter M, Karami O, Rahimi A, Offringa R, Keurentjes JJB, Balazadeh S, Smets E, Lens F. Intervessel pit membrane thickness best explains variation in embolism resistance amongst stems of Arabidopsis thaliana accessions. ANNALS OF BOTANY 2021; 128:171-182. [PMID: 33216143 PMCID: PMC8324034 DOI: 10.1093/aob/mcaa196] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/13/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS The ability to avoid drought-induced embolisms in the xylem is one of the essential traits for plants to survive periods of water shortage. Over the past three decades, hydraulic studies have been focusing on trees, which limits our ability to understand how herbs tolerate drought. Here we investigate the embolism resistance in inflorescence stems of four Arabidopsis thaliana accessions that differ in growth form and drought response. We assess functional traits underlying the variation in embolism resistance amongst the accessions studied using detailed anatomical observations. METHODS Vulnerability to xylem embolism was evaluated via vulnerability curves using the centrifuge technique and linked with detailed anatomical observations in stems using light microscopy and transmission electron microscopy. KEY RESULTS The data show significant differences in stem P50, varying 2-fold from -1.58 MPa in the Cape Verde Island accession to -3.07 MPa in the woody soc1 ful double mutant. Out of all the anatomical traits measured, intervessel pit membrane thickness (TPM) best explains the differences in P50, as well as P12 and P88. The association between embolism resistance and TPM can be functionally explained by the air-seeding hypothesis. There is no evidence that the correlation between increased woodiness and increased embolism resistance is directly related to functional aspects. However, we found that increased woodiness is strongly linked to other lignification characters, explaining why mechanical stem reinforcement is indirectly related to increased embolism resistance. CONCLUSIONS The woodier or more lignified accessions are more resistant to embolism than the herbaceous accessions, confirming the link between increased stem lignification and increased embolism resistance, as also observed in other lineages. Intervessel pit membrane thickness and, to a lesser extent, theoretical vessel implosion resistance and vessel wall thickness are the missing functional links between stem lignification and embolism resistance.
Collapse
Affiliation(s)
- Ajaree Thonglim
- Naturalis Biodiversity Center, Research Group Functional Traits, RA Leiden, The Netherlands
| | | | - Maximilian Larter
- Naturalis Biodiversity Center, Research Group Functional Traits, RA Leiden, The Netherlands
| | - Omid Karami
- Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, BE Leiden, the Netherlands
| | - Arezoo Rahimi
- Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, BE Leiden, the Netherlands
| | - Remko Offringa
- Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, BE Leiden, the Netherlands
| | - Joost J B Keurentjes
- Laboratory of Genetics, Wageningen University, Droevendaalsesteeg, PB Wageningen, The Netherlands
| | - Salma Balazadeh
- Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, BE Leiden, the Netherlands
| | - Erik Smets
- Naturalis Biodiversity Center, Research Group Functional Traits, RA Leiden, The Netherlands
| | - Frederic Lens
- Naturalis Biodiversity Center, Research Group Functional Traits, RA Leiden, The Netherlands
| |
Collapse
|
29
|
Park J, Ryu J, Park SH, Lee SJ. Air spread through a wetted deformable membrane: Implications for the mechanism of soft valves in plants. Phys Rev E 2021; 103:062407. [PMID: 34271721 DOI: 10.1103/physreve.103.062407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/22/2021] [Indexed: 11/07/2022]
Abstract
Plants have a special structure, torus-margo (TM) pit, which comprises a thickened torus at the center encircled by a highly porous margo. It is regarded as a key evolutionary structure to enable stable water transport, minimizing the air spread in the vessels. However, its valve-like dynamics to regulate two-phase flows still remains unclear even at a single pit level. Here, we study the air spreading dynamics using a bioinspired model of this soft pit valve. We divide it into the initial onset and the consecutive air-spreads, and propose the criteria of TM structures as the valve-like function. To delay the onset of air spread, the margo region should be thin and deformable enough to seal the pit aperture with the torus before the air penetration. Even after the onset, the membranes whose maximum pore size is smaller than its thickness can avoid continuous air-spread. The criteria also fit properly into botanical data on the morphologies of TM pits, implying that their valve-like behaviors may alleviate the tradeoff between hydraulic safety and efficiency at the single pit level. Our study would help to understand of the mechanistic pit-level strategy and also can provide insight into fluidic systems to control interfacial phenomena.
Collapse
Affiliation(s)
- Jooyoung Park
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Jeongeun Ryu
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Sung Ho Park
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| |
Collapse
|
30
|
Feng F, Losso A, Tyree M, Zhang S, Mayr S. Cavitation fatigue in conifers: a study on eight European species. PLANT PHYSIOLOGY 2021; 186:1580-1590. [PMID: 33905499 PMCID: PMC8260135 DOI: 10.1093/plphys/kiab170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
After drought-induced embolism and repair, tree xylem may be weakened against future drought events (cavitation fatigue). As there are few data on cavitation fatigue in conifers available, we quantified vulnerability curves (VCs) after embolism/repair cycles on eight European conifer species. We induced 50% and 100% loss of conductivity (LC) with a cavitron, and analyzed VCs. Embolism repair was obtained by vacuum infiltration. All species demonstrated complete embolism repair and a lack of any cavitation fatigue after 50% LC . After 100% LC, European larch (Larix decidua), stone pine (Pinus cembra), Norway spruce (Picea abies), and silver fir (Abies alba) remained unaffected, while mountain pine (Pinus mugo), yew (Taxus baccata), and common juniper (Juniperus communis) exhibited 0.4-0.9 MPa higher vulnerability to embolism. A small cavitation fatigue observed in Scots pine (Pinus sylvestris) was probably biased by incomplete embolism repair, as indicated by a correlation of vulnerability shifts and conductivity restoration. Our data demonstrate that cavitation fatigue in conifers is species-specific and depends on the intensity of preceding LC. The lack of fatigue effects after moderate LC, and relevant effects in only three species after high LC, indicate that conifers are relatively resistant against cavitation fatigue. This is remarkable considering the complex and delicate conifer pit architecture and may be important considering climate change projections.
Collapse
Affiliation(s)
- Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
| | - Melvin Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Shuoxin Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
| |
Collapse
|
31
|
Tomasella M, Casolo V, Natale S, Petruzzellis F, Kofler W, Beikircher B, Mayr S, Nardini A. Shade-induced reduction of stem nonstructural carbohydrates increases xylem vulnerability to embolism and impedes hydraulic recovery in Populus nigra. THE NEW PHYTOLOGIST 2021; 231:108-121. [PMID: 33811346 PMCID: PMC9290559 DOI: 10.1111/nph.17384] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/28/2021] [Indexed: 05/08/2023]
Abstract
Nonstructural carbohydrates (NSCs) have been suggested to affect xylem transport under fluctuating water availability, but conclusive evidence is still lacking. We tested the effect of shade-induced NSC depletion on xylem vulnerability to embolism and hydraulic recovery on Populus nigra saplings. Vulnerability was assessed in light-exposed (L) and shaded (S) plants with the hydraulic method, and in vivo with the optical method and X-ray micro-computed tomography. Plants were stressed to 80% loss of hydraulic conductance (PLC) and re-irrigated to check for possible recovery. We measured PLC, bark and wood NSC content, as well as xylem sap pH, surface tension (γsap ) and sugar concentration, before, during and after drought. Shading induced depletion of stem NSC (mainly starch) reserves. All methods converged in indicating higher xylem vulnerability in S than in L plants. This difference was not explained by xylem vessel and pit anatomy or by γsap . Shading impeded sap acidification and sugar accumulation during drought in S plants and prevented hydraulic recovery, which was observed in L plants. Our results highlight the importance of stem NSCs to sustain xylem hydraulic functioning during drought and suggest that light and/or adequate stem NSC thresholds are required to trigger xylem sap chemical changes involved in embolism recovery.
Collapse
Affiliation(s)
- Martina Tomasella
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Valentino Casolo
- Dipartimento di Scienze AgroalimentariAmbientali e AnimaliUniversità di UdineVia delle Scienze 91Udine33100Italy
| | - Sara Natale
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Werner Kofler
- Department of BotanyUniversity of InnsbruckSternwartestraße 15Innsbruck6020Austria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwartestraße 15Innsbruck6020Austria
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwartestraße 15Innsbruck6020Austria
| | - Andrea Nardini
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| |
Collapse
|
32
|
Słupianek A, Dolzblasz A, Sokołowska K. Xylem Parenchyma-Role and Relevance in Wood Functioning in Trees. PLANTS (BASEL, SWITZERLAND) 2021; 10:1247. [PMID: 34205276 PMCID: PMC8235782 DOI: 10.3390/plants10061247] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field.
Collapse
Affiliation(s)
- Aleksandra Słupianek
- Department of Plant Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland; (A.D.); (K.S.)
| | | | | |
Collapse
|
33
|
Kaack L, Weber M, Isasa E, Karimi Z, Li S, Pereira L, Trabi CL, Zhang Y, Schenk HJ, Schuldt B, Schmidt V, Jansen S. Pore constrictions in intervessel pit membranes provide a mechanistic explanation for xylem embolism resistance in angiosperms. THE NEW PHYTOLOGIST 2021; 230:1829-1843. [PMID: 33595117 DOI: 10.1111/nph.17282] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/09/2021] [Indexed: 05/27/2023]
Abstract
Embolism spreading in angiosperm xylem occurs via mesoporous pit membranes between vessels. Here, we investigate how the size of pore constrictions in pit membranes is related to pit membrane thickness and embolism resistance. Pit membranes were modelled as multiple layers to investigate how pit membrane thickness and the number of intervessel pits per vessel determine pore constriction sizes, the probability of encountering large pores, and embolism resistance. These estimations were complemented by measurements of pit membrane thickness, embolism resistance, and number of intervessel pits per vessel in stem xylem (n = 31, 31 and 20 species, respectively). The modelled constriction sizes in pit membranes decreased with increasing membrane thickness, explaining the measured relationship between pit membrane thickness and embolism resistance. The number of pits per vessel affected constriction size and embolism resistance much less than pit membrane thickness. Moreover, a strong relationship between modelled and measured embolism resistance was observed. Pore constrictions provide a mechanistic explanation for why pit membrane thickness determines embolism resistance, which suggests that hydraulic safety can be uncoupled from hydraulic efficiency. Although embolism spreading remains puzzling and encompasses more than pore constriction sizes, angiosperms are unlikely to have leaky pit membranes, which enables tensile transport of water.
Collapse
Affiliation(s)
- Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Matthias Weber
- Institute of Stochastics, Ulm University, Helmholtzstraße 18, Ulm, D-89069, Germany
| | - Emilie Isasa
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, Würzburg, D-97082, Germany
| | - Zohreh Karimi
- Department of Biology, Faculty of Sciences, Golestan University, Shahid Beheshti St., Gorgan, 15759-49138, Iran
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Christophe L Trabi
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Ya Zhang
- College of Life Sciences, Anhui Normal University, Beijingdong Road 1, Wuhu, 241000, China
| | - H Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA, 92834-6850, USA
| | - Bernhard Schuldt
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, Würzburg, D-97082, Germany
| | - Volker Schmidt
- Institute of Stochastics, Ulm University, Helmholtzstraße 18, Ulm, D-89069, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| |
Collapse
|
34
|
Wason J, Bouda M, Lee EF, McElrone AJ, Phillips RJ, Shackel KA, Matthews MA, Brodersen C. Xylem network connectivity and embolism spread in grapevine(Vitis vinifera L.). PLANT PHYSIOLOGY 2021; 186:373-387. [PMID: 33576825 PMCID: PMC8154096 DOI: 10.1093/plphys/kiab045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 01/17/2021] [Indexed: 05/20/2023]
Abstract
Xylem networks are vulnerable to the formation and spread of gas embolisms that reduce water transport. Embolisms spread through interconduit pits, but the three-dimensional (3D) complexity and scale of xylem networks means that the functional implications of intervessel connections are not well understood. Here, xylem networks of grapevine (Vitis vinifera L.) were reconstructed from 3D high-resolution X-ray micro-computed tomography (microCT) images. Xylem network performance was then modeled to simulate loss of hydraulic conductivity under increasingly negative xylem sap pressure simulating drought stress conditions. We also considered the sensitivity of xylem network performance to changes in key network parameters. We found that the mean pit area per intervessel connection was constant across 10 networks from three, 1.5-m stem segments, but short (0.5 cm) segments fail to capture complete network connectivity. Simulations showed that network organization imparted additional resistance to embolism spread beyond the air-seeding threshold of pit membranes. Xylem network vulnerability to embolism spread was most sensitive to variation in the number and location of vessels that were initially embolized and pit membrane vulnerability. Our results show that xylem network organization can increase stem resistance to embolism spread by 40% (0.66 MPa) and challenge the notion that a single embolism can spread rapidly throughout an entire xylem network.
Collapse
Affiliation(s)
- Jay Wason
- School of Forest Resources, University of Maine, Orono, Maine 04469
- School of the Environment, Yale University, New Haven, CT 06520
| | - Martin Bouda
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | - Eric F Lee
- Department of Engineering Sciences, Clackamas Community College, Oregon City, Oregon 97045
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California Davis, Davis, California
- Crops Pathology and Genetics Research Unit, USDA-ARS, Davis, California
| | - Ronald J Phillips
- Department of Chemical Engineering, University of California Davis, Davis, California
| | - Kenneth A Shackel
- Department of Plant Science, University of California Davis, Davis, California
| | - Mark A Matthews
- Department of Viticulture and Enology, University of California Davis, Davis, California
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06520
- Author for communication:
| |
Collapse
|
35
|
Guan X, Pereira L, McAdam SAM, Cao KF, Jansen S. No gas source, no problem: Proximity to pre-existing embolism and segmentation affect embolism spreading in angiosperm xylem by gas diffusion. PLANT, CELL & ENVIRONMENT 2021; 44:1329-1345. [PMID: 33529382 DOI: 10.1111/pce.14016] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/16/2021] [Accepted: 01/17/2021] [Indexed: 05/12/2023]
Abstract
Embolism spreading in dehydrating angiosperm xylem is driven by gas movement between embolized and sap-filled conduits. Here we examine how the proximity to pre-existing embolism and hydraulic segmentation affect embolism propagation. Based on the optical method, we compare xylem embolism resistance between detached leaves and leaves attached to branches, and between intact leaves and leaves with cut minor veins, for six species. Embolism resistance of detached leaves was significantly lower than that of leaves attached to stems, except for two species, with all vessels ending in their petioles. Cutting of minor veins showed limited embolism spreading in minor veins near the cuts prior to major veins. Moreover, despite strong agreement in the overall embolism resistance of detached leaves between the optical and pneumatic method, minor differences were observed during early stages of embolism formation. We conclude that embolism resistance may represent a relative trait due to an open-xylem artefact, with embolism spreading possibly affected by the proximity and connectivity to pre-existing embolism as a gas source, while hydraulic segmentation prevents such artefact. Since embolism formation may not rely on a certain pressure difference threshold between functional and embolized conduits, we speculate that embolism is facilitated by pressure-driven gas diffusion across pit membranes.
Collapse
Affiliation(s)
- Xinyi Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| |
Collapse
|
36
|
Vehmas T, Makkonen L. Metastable Nanobubbles. ACS OMEGA 2021; 6:8021-8027. [PMID: 33817461 PMCID: PMC8014917 DOI: 10.1021/acsomega.0c05384] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/04/2021] [Indexed: 05/06/2023]
Abstract
Water containing suspended nanobubbles is utilized in various applications. The observed lifetime of suspended nanobubbles is several weeks, whereas, according to the classical theory of bubble stability, a nanosized bubble should dissolve within microseconds. Explanations for the longevity of nanosized bubbles have been proposed but none of them has gained general acceptance. In this study, we derive an explanation for the existence of metastable nanobubbles solely from the thermodynamic principles. According to our analysis, the dissolution of nanosized aqueous bulk bubbles is nonspontaneous below 180 nm diameter due to the energy requirement of gas dissolution. Hydrophobic surfaces have a further stabilizing effect, and the dissolution becomes nonspontaneous in surface nanobubbles having a diameter below 600 nm.
Collapse
|
37
|
Why is Tree Drought Mortality so Hard to Predict? Trends Ecol Evol 2021; 36:520-532. [PMID: 33674131 DOI: 10.1016/j.tree.2021.02.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 01/18/2023]
Abstract
Widespread tree mortality following droughts has emerged as an environmentally and economically devastating 'ecological surprise'. It is well established that tree physiology is important in understanding drought-driven mortality; however, the accuracy of predictions based on physiology alone has been limited. We propose that complicating factors at two levels stymie predictions of drought-driven mortality: (i) organismal-level physiological and site factors that obscure understanding of drought exposure and vulnerability and (ii) community-level ecological interactions, particularly with biotic agents whose effects on tree mortality may reverse expectations based on stress physiology. We conclude with a path forward that emphasizes the need for an integrative approach to stress physiology and biotic agent dynamics when assessing forest risk to drought-driven morality in a changing climate.
Collapse
|
38
|
Schenk HJ, Michaud JM, Mocko K, Espino S, Melendres T, Roth MR, Welti R, Kaack L, Jansen S. Lipids in xylem sap of woody plants across the angiosperm phylogeny. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:1477-1494. [PMID: 33295003 DOI: 10.1111/tpj.15125] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Lipids have been observed attached to lumen-facing surfaces of mature xylem conduits of several plant species, but there has been little research on their functions or effects on water transport, and only one lipidomic study of the xylem apoplast. Therefore, we conducted lipidomic analyses of xylem sap from woody stems of seven plants representing six major angiosperm clades, including basal magnoliids, monocots and eudicots, to characterize and quantify phospholipids, galactolipids and sulfolipids in sap using mass spectrometry. Locations of lipids in vessels of Laurus nobilis were imaged using transmission electron microscopy and confocal microscopy. Xylem sap contained the galactolipids di- and monogalactosyldiacylglycerol, as well as all common plant phospholipids, but only traces of sulfolipids, with total lipid concentrations in extracted sap ranging from 0.18 to 0.63 nmol ml-1 across all seven species. Contamination of extracted sap from lipids in cut living cells was found to be negligible. Lipid composition of sap was compared with wood in two species and was largely similar, suggesting that sap lipids, including galactolipids, originate from cell content of living vessels. Seasonal changes in lipid composition of sap were observed for one species. Lipid layers coated all lumen-facing vessel surfaces of L. nobilis, and lipids were highly concentrated in inter-vessel pits. The findings suggest that apoplastic, amphiphilic xylem lipids are a universal feature of angiosperms. The findings require a reinterpretation of the cohesion-tension theory of water transport to account for the effects of apoplastic lipids on dynamic surface tension and hydraulic conductance in xylem.
Collapse
Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Joseph M Michaud
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Kerri Mocko
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Susana Espino
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Tatiana Melendres
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Mary R Roth
- Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Ruth Welti
- Kansas Lipidomics Research Center, Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| |
Collapse
|
39
|
Levionnois S, Jansen S, Wandji RT, Beauchêne J, Ziegler C, Coste S, Stahl C, Delzon S, Authier L, Heuret P. Linking drought-induced xylem embolism resistance to wood anatomical traits in Neotropical trees. THE NEW PHYTOLOGIST 2021; 229:1453-1466. [PMID: 32964439 DOI: 10.1111/nph.16942] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/04/2020] [Indexed: 05/27/2023]
Abstract
Drought-induced xylem embolism is considered to be one of the main factors driving mortality in woody plants worldwide. Although several structure-functional mechanisms have been tested to understand the anatomical determinants of embolism resistance, there is a need to study this topic by integrating anatomical data for many species. We combined optical, laser, and transmission electron microscopy to investigate vessel diameter, vessel grouping, and pit membrane ultrastructure for 26 tropical rainforest tree species across three major clades (magnoliids, rosiids, and asteriids). We then related these anatomical observations to previously published data on drought-induced embolism resistance, with phylogenetic analyses. Vessel diameter, vessel grouping, and pit membrane ultrastructure were all predictive of xylem embolism resistance, but with weak predictive power. While pit membrane thickness was a predictive trait when vestured pits were taken into account, the pit membrane diameter-to-thickness ratio suggests a strong importance of the deflection resistance of the pit membrane. However, phylogenetic analyses weakly support adaptive coevolution. Our results emphasize the functional significance of pit membranes for air-seeding in tropical rainforest trees, highlighting also the need to study their mechanical properties due to the link between embolism resistance and pit membrane diameter-to-thickness ratio. Finding support for adaptive coevolution also remains challenging.
Collapse
Affiliation(s)
- Sébastien Levionnois
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, 34000, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, D-89081, Germany
| | - Ruth Tchana Wandji
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| | - Jacques Beauchêne
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| | - Camille Ziegler
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
- AgroParisTech, UMR Silva, INRAE, Université de Lorraine, Nancy, F-54000, France
| | - Sabrina Coste
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| | - Clément Stahl
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| | - Sylvain Delzon
- UMR BIOGECO, INRAE, Université de Bordeaux, Pessac, 33615, France
| | - Louise Authier
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| | - Patrick Heuret
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou, 97310, France
| |
Collapse
|
40
|
Aritsara ANA, Razakandraibe VM, Ramananantoandro T, Gleason SM, Cao KF. Increasing axial parenchyma fraction in the Malagasy Magnoliids facilitated the co-optimisation of hydraulic efficiency and safety. THE NEW PHYTOLOGIST 2021; 229:1467-1480. [PMID: 32981106 DOI: 10.1111/nph.16969] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The evolution of angiosperms was accompanied by the segregation and specialisation of their xylem tissues. This study aimed to determine whether the fraction and arrangement of parenchyma tissue influence the hydraulic efficiency-safety trade-off in the basal angiosperms. We examined xylem anatomical structure and hydraulic functioning of 28 woody species of Magnoliids in a tropical rainforest of Madagascar and reported, for the first time, quantitative measurements that support the relationship between vessel-to-xylem parenchyma connectivity and the hydraulic efficiency-safety trade-off. We also introduced a new measurement - the distance of species from the trade-off limit - to quantify the co-optimisation of hydraulic efficiency and safety. Although the basal angiosperms in this study had low hydraulic conductivity and safety, species with higher axial parenchyma fraction (APf) had significantly higher hydraulic conductivity. Hydraulic efficiency-safety optimisation was accompanied by higher APf and vessel-to-axial parenchyma connectivity. Conversely, species exhibiting high ray parenchyma fraction and high vessel-to-ray connectivity had lower Ks and were further away from the hydraulic trade-off limit line. Our results provide evidence that axial parenchyma fraction and paratracheal arrangement are associated with both enhanced hydraulic efficiency and safety.
Collapse
Affiliation(s)
- Amy Ny Aina Aritsara
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, 530004, China
- Unité de Formation et de Recherche Sciences du Bois, Département Foresterie et Environnement, Ecole Supérieure des Sciences Agronomiques, Université d'Antananarivo, BP 175, Antananarivo, 101, Madagascar
| | - Vonjisoa M Razakandraibe
- Unité de Formation et de Recherche Sciences du Bois, Département Foresterie et Environnement, Ecole Supérieure des Sciences Agronomiques, Université d'Antananarivo, BP 175, Antananarivo, 101, Madagascar
| | - Tahiana Ramananantoandro
- Unité de Formation et de Recherche Sciences du Bois, Département Foresterie et Environnement, Ecole Supérieure des Sciences Agronomiques, Université d'Antananarivo, BP 175, Antananarivo, 101, Madagascar
| | - Sean M Gleason
- Water Management and Systems Research Unit, USDA-ARS, Fort Collins, CO, 80526, USA
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, 530004, China
| |
Collapse
|
41
|
Jansen S, Guan X, Kaack L, Trabi C, Miranda M, Ribeiro R, Pereira L. The Pneumatron estimates xylem embolism resistance in angiosperms based on gas diffusion kinetics: a mini-review. ACTA ACUST UNITED AC 2020. [DOI: 10.17660/actahortic.2020.1300.25] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
42
|
Olson ME. From Carlquist's ecological wood anatomy to Carlquist's Law: why comparative anatomy is crucial for functional xylem biology. AMERICAN JOURNAL OF BOTANY 2020; 107:1328-1341. [PMID: 33078405 DOI: 10.1002/ajb2.1552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
All students of xylem structure-function relations need to be familiar with the work of Sherwin Carlquist. He studies xylem through the lens of the comparative method, which uses the appearance of similar anatomical features under similar conditions of natural selection to infer function. "Function" in biology implies adaptation; maximally supported adaptation inferences require experimental and comparative xylem scientists to work with one another. Engaging with comparative inferences of xylem function will, more likely sooner rather than later, bring one to the work of Sherwin Carlquist. To mark his 90th birthday, I highlight just a few examples of his extraordinarily perceptive and general comparative insights. One is "Carlquist's Law", the pervasive tendency for vessels to be solitary when background cells are conductive. I cover his pioneering of "ecological" wood anatomy, viewing xylem variation as reflecting the effects of selection across climate and habit variation. Another is the embolism vulnerability-conduit diameter relationship, one of the most widely invoked structure-function relationships in xylem biology. I discuss the inferential richness within the notion of Carlquistian paedomorphosis, including detailed functional inferences regarding ray cell orientation. My final example comes from his very recent work offering the first satisfactory hypothesis accounting for the geographical and histological distribution of scalariform perforation plates as an adaptation, including "Carlquist's Ratchet", why scalariform plates are adaptive but do not re-evolve once lost. This extraordinarily rich production over six decades is filled with comparative inferences that should keep students of xylem function busy testing for decades to come.
Collapse
Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico, DF, 04510, México
| |
Collapse
|
43
|
De Roo L, Salomón RL, Oleksyn J, Steppe K. Woody tissue photosynthesis delays drought stress in Populus tremula trees and maintains starch reserves in branch xylem tissues. THE NEW PHYTOLOGIST 2020; 228:70-81. [PMID: 32416019 DOI: 10.1111/nph.16662] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Photosynthesis in woody tissues (Pwt ) is less sensitive to water shortage than in leaves, hence, Pwt might be a crucial carbon source to alleviate drought stress. To evaluate the impact of Pwt on tree drought tolerance, woody tissues of 4-m-tall drought-stressed Populus tremula trees were subjected to a light-exclusion treatment across the entire plant to inhibit Pwt . Xylem water potential (Ψxylem ), sap flow ( FH2O ), leaf net photosynthesis (Pn,l ), stem diameter variations (ΔD), in vivo acoustic emissions in stems (AEs) and nonstructural carbohydrate concentrations ([NSC]) were monitored to comprehensively assess water and carbon relations at whole-tree level. Under well-watered conditions, Pwt kept Ψxylem at a higher level, lowered FH2O and had no effect on [NSC]. Under drought, Ψxylem , FH2O and Pn,l in light-excluded trees rapidly decreased in concert with reductions in branch xylem starch concentration. Moreover, sub-daily patterns of ΔD, FH2O and AEs were strongly related, suggesting that in vivo AEs may inform not only about embolism events, but also about capacitive release and replenishment of stem water pools. Results highlight the importance of Pwt in maintaining xylem hydraulic integrity under drought conditions and in sustaining NSC pools to potentially limit increases in xylem tension.
Collapse
Affiliation(s)
- Linus De Roo
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - Roberto Luis Salomón
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - Jacek Oleksyn
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, PL-62-035, Kórnik, Poland
| | - Kathy Steppe
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| |
Collapse
|
44
|
Chen Z, Zhu S, Zhang Y, Luan J, Li S, Sun P, Wan X, Liu S. Tradeoff between storage capacity and embolism resistance in the xylem of temperate broadleaf tree species. TREE PHYSIOLOGY 2020; 40:1029-1042. [PMID: 32310276 DOI: 10.1093/treephys/tpaa046] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
Collapse
Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian 271018, China
| | - Junwei Luan
- Key Laboratory of Bamboo and Rattan Science and Technology, Institute for Resources and Environment, International Centre for Bamboo and Rattan, National Forestry and Grassland Administration, Beijing 100102, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
| | - Pengsen Sun
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| |
Collapse
|
45
|
Paljakka T, Rissanen K, Vanhatalo A, Salmon Y, Jyske T, Prisle NL, Linnakoski R, Lin JJ, Laakso T, Kasanen R, Bäck J, Hölttä T. Is Decreased Xylem Sap Surface Tension Associated With Embolism and Loss of Xylem Hydraulic Conductivity in Pathogen-Infected Norway Spruce Saplings? FRONTIERS IN PLANT SCIENCE 2020; 11:1090. [PMID: 32765568 PMCID: PMC7378778 DOI: 10.3389/fpls.2020.01090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 07/02/2020] [Indexed: 05/23/2023]
Abstract
Increased abiotic stress along with increasing temperatures, dry periods and forest disturbances may favor biotic stressors such as simultaneous invasion of bark beetle and ophiostomatoid fungi. It is not fully understood how tree desiccation is associated with colonization of sapwood by fungi. A decrease in xylem sap surface tension (σxylem) as a result of infection has been hypothesized to cause xylem embolism by lowering the threshold for air-seeding at the pits between conduits and disruptions in tree water transport. However, this hypothesis has not yet been tested. We investigated tree water relations by measuring the stem xylem hydraulic conductivity (Kstem), σxylem, stem relative water content (RWCstem), and water potential (Ψstem), and canopy conductance (gcanopy), as well as the compound composition in xylem sap in Norway spruce (Picea abies) saplings. We conducted our measurements at the later stage of Endoconidiophora polonica infection when visible symptoms had occurred in xylem. Saplings of two clones (44 trees altogether) were allocated to treatments of inoculated, wounded control and intact control trees in a greenhouse. The saplings were destructively sampled every second week during summer 2016. σxylem, Kstem and RWCstem decreased following the inoculation, which may indicate that decreased σxylem resulted in increased embolism. gcanopy did not differ between treatments indicating that stomata responded to Ψstem rather than to embolism formation. Concentrations of quinic acid, myo-inositol, sucrose and alkylphenol increased in the xylem sap of inoculated trees. Myo-inositol concentrations also correlated negatively with σxylem and Kstem. Our study is a preliminary investigation of the role of σxylem in E. polonica infected trees based on previous hypotheses. The results suggest that E. polonica infection can lead to a simultaneous decrease in xylem sap surface tension and a decline in tree hydraulic conductivity, thus hampering tree water transport.
Collapse
Affiliation(s)
- Teemu Paljakka
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Kaisa Rissanen
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Anni Vanhatalo
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Yann Salmon
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - Tuula Jyske
- Natural Resources Institute Finland (Luke), Espoo, Finland
| | - Nønne L. Prisle
- Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
| | | | - Jack J. Lin
- Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
| | - Tapio Laakso
- Natural Resources Institute Finland (Luke), Espoo, Finland
| | - Risto Kasanen
- Forest Sciences/Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Jaana Bäck
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
- Forest Sciences/Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
- Forest Sciences/Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| |
Collapse
|
46
|
Cavitation in lipid bilayers poses strict negative pressure stability limit in biological liquids. Proc Natl Acad Sci U S A 2020; 117:10733-10739. [PMID: 32358185 DOI: 10.1073/pnas.1917195117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Biological and technological processes that involve liquids under negative pressure are vulnerable to the formation of cavities. Maximal negative pressures found in plants are around -100 bar, even though cavitation in pure bulk water only occurs at much more negative pressures on the relevant timescales. Here, we investigate the influence of small solutes and lipid bilayers, both constituents of all biological liquids, on the formation of cavities under negative pressures. By combining molecular dynamics simulations with kinetic modeling, we quantify cavitation rates on biologically relevant length scales and timescales. We find that lipid bilayers, in contrast to small solutes, increase the rate of cavitation, which remains unproblematically low at the pressures found in most plants. Only when the negative pressures approach -100 bar does cavitation occur on biologically relevant timescales. Our results suggest that bilayer-based cavitation is what generally limits the magnitude of negative pressures in liquids that contain lipid bilayers.
Collapse
|
47
|
Yang J, M Michaud J, Jansen S, Schenk HJ, Zuo YY. Dynamic surface tension of xylem sap lipids. TREE PHYSIOLOGY 2020; 40:433-444. [PMID: 32031666 DOI: 10.1093/treephys/tpaa006] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 11/01/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
The surface tension of xylem sap has been traditionally assumed to be close to that of the pure water because decreasing surface tension is thought to increase vulnerability to air seeding and embolism. However, xylem sap contains insoluble lipid-based surfactants, which also coat vessel and pit membrane surfaces, where gas bubbles can enter xylem under negative pressure in the process known as air seeding. Because of the insolubility of amphiphilic lipids, the surface tension influencing air seeding in pit pores is not the equilibrium surface tension of extracted bulk sap but the local surface tension at gas-liquid interfaces, which depends dynamically on the local concentration of lipids per surface area. To estimate the dynamic surface tension in lipid layers that line surfaces in the xylem apoplast, we studied the time-dependent and surface area-regulated surface tensions of apoplastic lipids extracted from xylem sap of four woody angiosperm plants using constrained drop surfactometry. Xylem lipids were found to demonstrate potent surface activity, with surface tensions reaching an equilibrium at ~25 mN m-1 and varying between a minimum of 19 mN m-1 and a maximum of 68 mN m-1 when changing the surface area between 50 and 160% around the equilibrium surface area. It is concluded that xylem lipid films in natural conditions most likely range from nonequilibrium metastable conditions of a supersaturated compression state to an undersaturated expansion state, depending on the local surface areas of gas-liquid interfaces. Together with findings that maximum pore constrictions in angiosperm pit membranes are much smaller than previously assumed, low dynamic surface tension in xylem turns out to be entirely compatible with the cohesion-tension and air-seeding theories, as well as with the existence of lipid-coated nanobubbles in xylem sap, and with the range of vulnerabilities to embolism observed in plants.
Collapse
Affiliation(s)
- Jinlong Yang
- Department of Mechanical Engineering, University of Hawaii at Manoa, 2540 Dole Street, Holmes Hall 302, Honolulu, HI 96822, USA
| | - Joseph M Michaud
- Department of Biological Science, California State University, 800 N. State College Blvd., Fullerton, CA 92831, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm D-89081, Germany
| | - H Jochen Schenk
- Department of Biological Science, California State University, 800 N. State College Blvd., Fullerton, CA 92831, USA
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, 2540 Dole Street, Holmes Hall 302, Honolulu, HI 96822, USA
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, 1319 Punahou Street, Honolulu, HI 96826, USA
| |
Collapse
|
48
|
Janssen TAJ, Hölttä T, Fleischer K, Naudts K, Dolman H. Wood allocation trade-offs between fiber wall, fiber lumen, and axial parenchyma drive drought resistance in neotropical trees. PLANT, CELL & ENVIRONMENT 2020; 43:965-980. [PMID: 31760666 PMCID: PMC7155043 DOI: 10.1111/pce.13687] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 05/25/2023]
Abstract
Functional relationships between wood density and measures of xylem hydraulic safety and efficiency are ambiguous, especially in wet tropical forests. In this meta-analysis, we move beyond wood density per se and identify relationships between xylem allocated to fibers, parenchyma, and vessels and measures of hydraulic safety and efficiency. We analyzed published data of xylem traits, hydraulic properties and measures of drought resistance from neotropical tree species retrieved from 346 sources. We found that xylem volume allocation to fiber walls increases embolism resistance, but at the expense of specific conductivity and sapwood capacitance. Xylem volume investment in fiber lumen increases capacitance, while investment in axial parenchyma is associated with higher specific conductivity. Dominant tree taxa from wet forests prioritize xylem allocation to axial parenchyma at the expense of fiber walls, resulting in a low embolism resistance for a given wood density and a high vulnerability to drought-induced mortality. We conclude that strong trade-offs between xylem allocation to fiber walls, fiber lumen, and axial parenchyma drive drought resistance in neotropical trees. Moreover, the benefits of xylem allocation to axial parenchyma in wet tropical trees might not outweigh the consequential low embolism resistance under more frequent and severe droughts in a changing climate.
Collapse
Affiliation(s)
- Thomas A. J. Janssen
- Department of Earth Sciences, Cluster Earth and ClimateVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Katrin Fleischer
- Land Surface‐Atmosphere InteractionsTechnical University of MunichFreisingGermany
| | - Kim Naudts
- Department of Earth Sciences, Cluster Earth and ClimateVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Han Dolman
- Department of Earth Sciences, Cluster Earth and ClimateVrije Universiteit AmsterdamAmsterdamThe Netherlands
| |
Collapse
|
49
|
Kotowska MM, Wright IJ, Westoby M. Parenchyma Abundance in Wood of Evergreen Trees Varies Independently of Nutrients. FRONTIERS IN PLANT SCIENCE 2020; 11:86. [PMID: 32180778 PMCID: PMC7045414 DOI: 10.3389/fpls.2020.00086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 01/21/2020] [Indexed: 05/25/2023]
Abstract
The abundance of living cells in wood-mainly as interconnected axial and ray parenchyma networks-varies widely between species. However, the functional significance of this variation and its role in plant ecological strategies is poorly understood, as is the extent to which different parenchyma fractions are favored in relation to soil nutrients and hydraulic functions. We analyzed wood tissue fractions of 16 Australian angiosperm species sampled from two nearby areas with similar climate but very different soil nutrient profiles and investigated structure-function links with soil and tissue nutrient concentrations and other plant traits. We expected the variation in parenchyma fractions to influence nutrient concentrations in wood xylem, and to find species with lower parenchyma fractions and accordingly lower nutrient requirements on lower-nutrient soils. Surprisingly, both axial and ray parenchyma fractions were mostly unrelated to tissue and soil nutrient concentrations, except for nitrogen concentration in stem sapwood. Species from low nutrient soils showed higher fractional P translocation from both leaves and sapwood, but little patterning with respect to tissue nitrogen. While species from high and low nutrient soils clearly clustered along the soil-fertility axis, their tissue composition varied independently from plant functional traits related to construction costs and hydraulic anatomy. Our findings imply that there is considerable variation among species in the nutrient concentrations within different parenchyma tissues. The anatomical composition of wood tissue seems unrelated to plant nutrient requirements. Even though xylem parenchyma is involved in metabolic functions such as nutrient translocation and storage, parenchyma abundance on its own does not directly explain variation in these functions, even in co-occurring species. While parenchyma is highly abundant in wood of angiosperm trees, we are still lacking a convincing ecological interpretation of its variability and role in whole-tree nutrient budgets.
Collapse
Affiliation(s)
- Martyna M. Kotowska
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- Department of Plant Ecology and Ecosystems Research, University of Göttingen, Göttingen, Germany
| | - Ian J. Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| |
Collapse
|
50
|
Li S, Wang J, Yin Y, Li X, Deng L, Jiang X, Chen Z, Li Y. Investigating Effects of Bordered Pit Membrane Morphology and Properties on Plant Xylem Hydraulic Functions-A Case Study from 3D Reconstruction and Microflow Modelling of Pit Membranes in Angiosperm Xylem. PLANTS (BASEL, SWITZERLAND) 2020; 9:E231. [PMID: 32054100 PMCID: PMC7076482 DOI: 10.3390/plants9020231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/18/2020] [Accepted: 02/08/2020] [Indexed: 01/12/2023]
Abstract
Pit membranes in between neighboring conduits of xylem play a crucial role in plant water transport. In this review, the morphological characteristics, chemical composition and mechanical properties of bordered pit membranes were summarized and linked with their functional roles in xylem hydraulics. The trade-off between xylem hydraulic efficiency and safety was closely related with morphology and properties of pit membranes, and xylem embolism resistance was also determined by the pit membrane morphology and properties. Besides, to further investigate the effects of bordered pit membranes morphology and properties on plant xylem hydraulic functions, here we modelled three-dimensional structure of bordered pit membranes by applying a deposition technique. Based on reconstructed 3D pit membrane structures, a virtual fibril network was generated to model the microflow pattern across inter-vessel pit membranes. Moreover, the mechanical behavior of intervessel pit membranes was estimated from a single microfibril's mechanical property. Pit membranes morphology varied among different angiosperm and gymnosperm species. Our modelling work suggested that larger pores of pit membranes do not necessarily contribute to major flow rate across pit membranes; instead, the obstructed degree of flow pathway across the pit membranes plays a more important role. Our work provides useful information for studying the mechanism of microfluid flow transport across pit membranes and also sheds light on investigating the response of pit membranes both at normal and stressed conditions, thus improving our understanding on functional roles of pit membranes in xylem hydraulic function. Further work could be done to study the morphological and mechanical response of bordered pit membranes under different dehydrated conditions, as well as the related microflow behavior, based on our constructed model.
Collapse
Affiliation(s)
- Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Jie Wang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Yafang Yin
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Xin Li
- College of Forestry, Beijing Forestry University, Beijing 100083, China;
| | - Liping Deng
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- International Center for Bamboo and Rattan, Beijing 100102, China
| | - Xiaomei Jiang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Zhicheng Chen
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing 100083, China;
| | - Yujun Li
- School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
| |
Collapse
|