1
|
Griffani DS, Rognon P, Farquhar GD. The role of thermodiffusion in transpiration. THE NEW PHYTOLOGIST 2024; 243:1301-1311. [PMID: 38453691 DOI: 10.1111/nph.19642] [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: 07/26/2023] [Accepted: 01/28/2024] [Indexed: 03/09/2024]
Abstract
Plant leaf temperatures can differ from ambient air temperatures. A temperature gradient in a gas mixture gives rise to a phenomenon known as thermodiffusion, which operates in addition to ordinary diffusion. Whilst transpiration is generally understood to be driven solely by the ordinary diffusion of water vapour along a concentration gradient, we consider the implications of thermodiffusion for transpiration. We develop a new modelling framework that introduces the effects of thermodiffusion on the transpiration rate, E. By applying this framework, we quantify the proportion of E attributable to thermodiffusion for a set of physiological and environmental conditions, varied over a wide range. Thermodiffusion is found to be most significant (in some cases > 30% of E) when a leaf-to-air temperature difference coincides with a relatively small water vapour concentration difference across the boundary layer; a boundary layer conductance that is large as compared to the stomatal conductance; or a relatively low transpiration rate. Thermodiffusion also alters the conditions required for the onset of reverse transpiration, and the rate at which this water vapour uptake occurs.
Collapse
Affiliation(s)
- Danielle S Griffani
- Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW, 2480, Australia
| | - Pierre Rognon
- School of Civil Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
| |
Collapse
|
2
|
Cernusak LA, Wong SC, Stuart-Williams H, Márquez DA, Pontarin N, Farquhar GD. Unsaturation in the air spaces of leaves and its implications. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38867619 DOI: 10.1111/pce.15001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/26/2024] [Accepted: 05/31/2024] [Indexed: 06/14/2024]
Abstract
Modern plant physiological theory stipulates that the resistance to water movement from plants to the atmosphere is overwhelmingly dominated by stomata. This conception necessitates a corollary assumption-that the air spaces in leaves must be nearly saturated with water vapour; that is, with a relative humidity that does not decline materially below unity. As this idea became progressively engrained in scientific discourse and textbooks over the last century, observations inconsistent with this corollary assumption were occasionally reported. Yet, evidence of unsaturation gained little traction, with acceptance of the prevailing framework motivated by three considerations: (1) leaf water potentials measured by either thermocouple psychrometry or the Scholander pressure chamber are largely consistent with the framework; (2) being able to assume near saturation of intercellular air spaces was transformational to leaf gas exchange analysis; and (3) there has been no obvious mechanism to explain a variable, liquid-phase resistance in the leaf mesophyll. Here, we review the evidence that refutes the assumption of universal, near saturation of air spaces in leaves. Refining the prevailing paradigm with respect to this assumption provides opportunities for identifying and developing mechanisms for increased plant productivity in the face of increasing evaporative demand imposed by global climate change.
Collapse
Affiliation(s)
- Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Suan Chin Wong
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Hilary Stuart-Williams
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Diego A Márquez
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Nicole Pontarin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| |
Collapse
|
3
|
Hussain SB, Stinziano J, Pierre MO, Vincent C. Accurate photosynthetic parameter estimation at low stomatal conductance: effects of cuticular conductance and instrumental noise. PHOTOSYNTHESIS RESEARCH 2024; 160:111-124. [PMID: 38700726 PMCID: PMC11108943 DOI: 10.1007/s11120-024-01092-8] [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: 09/27/2023] [Accepted: 03/08/2024] [Indexed: 05/22/2024]
Abstract
Accurate estimation of photosynthetic parameters is essential for understanding plant physiological limitations and responses to environmental factors from the leaf to the global scale. Gas exchange is a useful tool to measure responses of net CO2 assimilation (A) to internal CO2 concentration (Ci), a necessary step in estimating photosynthetic parameters including the maximum rate of carboxylation (Vcmax) and the electron transport rate (Jmax). However, species and environmental conditions of low stomatal conductance (gsw) reduce the signal-to-noise ratio of gas exchange, challenging estimations of Ci. Previous works showed that not considering cuticular conductance to water (gcw) can lead to significant errors in estimating Ci, because it has a different effect on total conductance to CO2 (gtc) than does gsw. Here we present a systematic assessment of the need for incorporating gcw into Ci estimates. In this study we modeled the effect of gcw and of instrumental noise and quantified these effects on photosynthetic parameters in the cases of four species with varying gsw and gcw, measured using steady-state and constant ramping techniques, like the rapid A/Ci response method. We show that not accounting for gcw quantitatively influences Ci and the resulting Vcmax and Jmax, particularly when gcw exceeds 7% of the total conductance to water. The influence of gcw was not limited to low gsw species, highlighting the importance of species-specific knowledge before assessing A/Ci curves. Furthermore, at low gsw instrumental noise can affect Ci estimation, but the effect of instrumental noise can be minimized using constant-ramping rather than steady-state techniques. By incorporating these considerations, more precise measurements and interpretations of photosynthetic parameters can be obtained in a broader range of species and environmental conditions.
Collapse
Affiliation(s)
- Syed Bilal Hussain
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, 33850, USA
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland
| | - Joseph Stinziano
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
- Plant Health Science Directorate, Canadian Food Inspection Agency, 1400 Merivale Rd, Ottawa, ON, K2C 4B5, Canada
| | - Myrtho O Pierre
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, 33850, USA
| | - Christopher Vincent
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, 33850, USA.
| |
Collapse
|
4
|
Leverett A, Kromdijk J. The long and tortuous path towards improving photosynthesis by engineering elevated mesophyll conductance. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38804598 DOI: 10.1111/pce.14940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/13/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024]
Abstract
The growing demand for global food production is likely to be a defining issue facing humanity over the next 50 years. To tackle this challenge, there is a desire to bioengineer crops with higher photosynthetic efficiencies, to increase yields. Recently, there has been a growing interest in engineering leaves with higher mesophyll conductance (gm), which would allow CO2 to move more efficiently from the substomatal cavities to the chloroplast stroma. However, if crop yield gains are to be realised through this approach, it is essential that the methodological limitations associated with estimating gm are fully appreciated. In this review, we summarise these limitations, and outline the uncertainties and assumptions that can affect the final estimation of gm. Furthermore, we critically assess the predicted quantitative effect that elevating gm will have on assimilation rates in crop species. We highlight the need for more theoretical modelling to determine whether altering gm is truly a viable route to improve crop performance. Finally, we offer suggestions to guide future research on gm, which will help mitigate the uncertainty inherently associated with estimating this parameter.
Collapse
Affiliation(s)
- Alistair Leverett
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Johannes Kromdijk
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
5
|
Tejera-Nieves M, Seong DY, Reist L, Walker BJ. The Dynamic Assimilation Technique measures photosynthetic CO2 response curves with similar fidelity to steady-state approaches in half the time. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2819-2828. [PMID: 38366564 PMCID: PMC11103103 DOI: 10.1093/jxb/erae057] [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: 10/18/2023] [Accepted: 02/14/2024] [Indexed: 02/18/2024]
Abstract
The net CO2 assimilation (A) response to intercellular CO2 concentration (Ci) is a fundamental measurement in photosynthesis and plant physiology research. The conventional A/Ci protocols rely on steady-state measurements and take 15-40 min per measurement, limiting data resolution or biological replication. Additionally, there are several CO2 protocols employed across the literature, without clear consensus as to the optimal protocol or systematic biases in their estimations. We compared the non-steady-state Dynamic Assimilation Technique (DAT) protocol and the three most used CO2 protocols in steady-state measurements, and tested whether different CO2 protocols lead to systematic differences in estimations of the biochemical limitations to photosynthesis. The DAT protocol reduced the measurement time by almost half without compromising estimation accuracy or precision. The monotonic protocol was the fastest steady-state method. Estimations of biochemical limitations to photosynthesis were very consistent across all CO2 protocols, with slight differences in Rubisco carboxylation limitation. The A/Ci curves were not affected by the direction of the change of CO2 concentration but rather the time spent under triose phosphate utilization (TPU)-limited conditions. Our results suggest that the maximum rate of Rubisco carboxylation (Vcmax), linear electron flow for NADPH supply (J), and TPU measured using different protocols within the literature are comparable, or at least not systematically different based on the measurement protocol used.
Collapse
Affiliation(s)
- Mauricio Tejera-Nieves
- MSU-DOE Plant Research Laboratory, Michigan State University, 612 Wilson Rd, East Lansing, MI 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, 1129 Farm Ln, East Lansing, MI 48824, USA
| | - Do Young Seong
- Department of Medical Informatics, College of Medicine, Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| | - Lucas Reist
- Department of Biochemistry & Molecular Biology, Michigan State University, Molecular Plant Sciences Building, 1066 Bogue Street, East Lansing, MI 48824, USA
| | - Berkley J Walker
- MSU-DOE Plant Research Laboratory, Michigan State University, 612 Wilson Rd, East Lansing, MI 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, 1129 Farm Ln, East Lansing, MI 48824, USA
- Department of Plant Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI 48824, USA
| |
Collapse
|
6
|
Busch FA, Ainsworth EA, Amtmann A, Cavanagh AP, Driever SM, Ferguson JN, Kromdijk J, Lawson T, Leakey ADB, Matthews JSA, Meacham-Hensold K, Vath RL, Vialet-Chabrand S, Walker BJ, Papanatsiou M. A guide to photosynthetic gas exchange measurements: Fundamental principles, best practice and potential pitfalls. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38321805 DOI: 10.1111/pce.14815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/31/2023] [Indexed: 02/08/2024]
Abstract
Gas exchange measurements enable mechanistic insights into the processes that underpin carbon and water fluxes in plant leaves which in turn inform understanding of related processes at a range of scales from individual cells to entire ecosytems. Given the importance of photosynthesis for the global climate discussion it is important to (a) foster a basic understanding of the fundamental principles underpinning the experimental methods used by the broad community, and (b) ensure best practice and correct data interpretation within the research community. In this review, we outline the biochemical and biophysical parameters of photosynthesis that can be investigated with gas exchange measurements and we provide step-by-step guidance on how to reliably measure them. We advise on best practices for using gas exchange equipment and highlight potential pitfalls in experimental design and data interpretation. The Supporting Information contains exemplary data sets, experimental protocols and data-modelling routines. This review is a community effort to equip both the experimental researcher and the data modeller with a solid understanding of the theoretical basis of gas-exchange measurements, the rationale behind different experimental protocols and the approaches to data interpretation.
Collapse
Affiliation(s)
- Florian A Busch
- School of Biosciences and Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
- Research School of Biology, The Australian National University, Canberra, Australian Captial Territory, Australia
| | | | - Anna Amtmann
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Amanda P Cavanagh
- School of Life Sciences, University of Essex, Colchester, UK
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - John N Ferguson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Johannes Kromdijk
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Andrew D B Leakey
- Departments of Plant Biology and Crop Sciences, University of Illinois Urbana Champaign, Urbana, Illinois, USA
| | | | | | - Richard L Vath
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- LI-COR Environmental, Lincoln, Nebraska, USA
| | - Silvere Vialet-Chabrand
- Department of Plant Sciences, Horticulture and Product Physiology, Wageningen, The Netherlands
| | - Berkley J Walker
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Maria Papanatsiou
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| |
Collapse
|
7
|
Lupo Y, Moshelion M. The balance of survival: Comparative drought response in wild and domesticated tomatoes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 339:111928. [PMID: 37992898 DOI: 10.1016/j.plantsci.2023.111928] [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: 09/03/2023] [Revised: 11/12/2023] [Accepted: 11/17/2023] [Indexed: 11/24/2023]
Abstract
Plants have the ability to undergo reversible behavioral, morphological, or physiological changes in response to environmental conditions. This plasticity enables plants to cope with uncertain environmental conditions, such as drought. A primary plastic trait is the rate of stomatal response to changes in ambient conditions, which determines the amount of water lost via transpiration, as well as levels of CO2 absorption, growth, and productivity. Here, we examined the differences between domesticated (S. lycopersicum cv. M82) and wild tomato (S. pennellii) species and their responses to drought stress. The plants were grown in pots in a functional phenotyping platform (FPP) in a semi-controlled environment greenhouse. We found that the domesticated tomato had a higher transpiration rate (E) and higher stomatal conductance (gs). The domesticated tomato also had greater biomass and greater leaf area under drought conditions, as compared to the wild tomato. Despite the domesticated tomato's higher E and higher gs, there was no difference between the photosynthetic rates (An) of the two lines. Moreover, the wild tomato had a higher maximum rate of rubisco activity (Vcmax), which might explain its greater leaf level and whole canopy water-use efficiency. The domesticated tomato's higher E and greater leaf area led to its earlier exposure to drought stress, as compared to the wild tomato, which maintained higher levels of soil water, enabling it to maintain steady rates of whole-canopy stomatal conductance (gsc) for extended periods. The wild tomato was also more sensitive to soil water availability and lowered its maximum transpiration rate (Emax) at a higher soil-water-content (SWC) level compared to the domesticated species. Our results suggest that the domestication of tomatoes favored morphological/anatomical performance traits over physiological efficiency.
Collapse
Affiliation(s)
- Yaniv Lupo
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker, Israel
| | - Menachem Moshelion
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| |
Collapse
|
8
|
Walker BJ, Driever SM, Kromdijk J, Lawson T, Busch FA. Tools for Measuring Photosynthesis at Different Scales. Methods Mol Biol 2024; 2790:1-26. [PMID: 38649563 DOI: 10.1007/978-1-0716-3790-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Measurements of in vivo photosynthesis are powerful tools that probe the largest fluxes of carbon and energy in an illuminated leaf, but often the specific techniques used are so varied and specialized that it is difficult for researchers outside the field to select and perform the most useful assays for their research questions. The goal of this chapter is to provide a broad overview of the current tools available for the study of photosynthesis, both in vivo and in vitro, so as to provide a foundation for selecting appropriate techniques, many of which are presented in detail in subsequent chapters. This chapter will also organize current methods into a comparative framework and provide examples of how they have been applied to research questions of broad agronomical, ecological, or biological importance. This chapter closes with an argument that the future of in vivo measurements of photosynthesis lies in the ability to use multiple methods simultaneously and discusses the benefits of this approach to currently open physiological questions. This chapter, combined with the relevant methods chapters, could serve as a laboratory course in methods in photosynthesis research or as part of a more comprehensive laboratory course in general plant physiology methods.
Collapse
Affiliation(s)
- Berkley J Walker
- Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University and Research, Wageningen, The Netherlands
| | - Johannes Kromdijk
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK.
| |
Collapse
|
9
|
Lamour J, Souza DC, Gimenez BO, Higuchi N, Chave J, Chambers J, Rogers A. Wood-density has no effect on stomatal control of leaf-level water use efficiency in an Amazonian forest. PLANT, CELL & ENVIRONMENT 2023; 46:3806-3821. [PMID: 37635450 DOI: 10.1111/pce.14704] [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: 03/24/2023] [Revised: 07/20/2023] [Accepted: 08/16/2023] [Indexed: 08/29/2023]
Abstract
Forest disturbances increase the proportion of fast-growing tree species compared to slow-growing ones. To understand their relative capacity for carbon uptake and their vulnerability to climate change, and to represent those differences in Earth system models, it is necessary to characterise the physiological differences in their leaf-level control of water use efficiency and carbon assimilation. We used wood density as a proxy for the fast-slow growth spectrum and tested the assumption that trees with a low wood density (LWD) have a lower water-use efficiency than trees with a high wood density (HWD). We selected 5 LWD tree species and 5 HWD tree species growing in the same location in an Amazonian tropical forest and measured in situ steady-state gas exchange on top-of-canopy leaves with parallel sampling and measurement of leaf mass area and leaf nitrogen content. We found that LWD species invested more nitrogen in photosynthetic capacity than HWD species, had higher photosynthetic rates and higher stomatal conductance. However, contrary to expectations, we showed that the stomatal control of the balance between transpiration and carbon assimilation was similar in LWD and HWD species and that they had the same dark respiration rates.
Collapse
Affiliation(s)
- Julien Lamour
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Daisy C Souza
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Bruno O Gimenez
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
- Department of Geography, University of California, Berkeley, California, USA
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Jérôme Chave
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Jeffrey Chambers
- Department of Geography, University of California, Berkeley, California, USA
| | - Alistair Rogers
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
| |
Collapse
|
10
|
Meng Y, Wu Q, Zhou H, Hu H. How tank-mix adjuvant type and concentration influence the contact angle on wheat leaf surface. PeerJ 2023; 11:e16464. [PMID: 38025725 PMCID: PMC10668805 DOI: 10.7717/peerj.16464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Currently, the utilization of unmanned aerial vehicles (UAVs) for spraying pesticides is a prevalent issue in Asian countries. Improving the pesticide efficiency of UAV spraying is a major challenge for researchers. One of the factors that affect the efficiency is the wetting property of the spraying solutions on crop leaves. Tank-mix adjuvants, which can modify the wetting ability of the solutions, are often used for foliar application. However, different types and concentrations of tank-mix adjuvants may have different impacts on the wetting properties of droplets. In this article, we investigated the effects of four tank-mix adjuvants, Beidatong (BDT), Velezia Pro (VP), Nongjianfei (NJF), and Lieying (LY), on the dynamic contact angle (CA) values of droplets on the adaxial surface of wheat leaves. We measured the dynamic CA values of various concentrations of each adjuvant solution and determined the optimal concentrations based on the CA values, droplet spreading time, and cost. The results showed that adding any of the four adjuvants decreased the CA values, but the patterns of decrease varied among them. The CAs of BDT and VP solutions decreased slowly during the observation time (0-8.13 s), while those of NJF and LY solutions decreased rapidly throughout the observation period. According to the dynamic CA values of different concentrations, the optimal concentrations of BDT, VP, NJF, and LY for wheat field application were 12%, 16%, 6‰, and 0.3‰, respectively. Alkoxy-modified polytrisiloxane adjuvant (LY) could be recommended as an appropriate tank-mix adjuvant for wheat field application, considering spreading efficiency and cost. This study provides theoretical and practical guidance for selecting and optimizing tank-mix adjuvants for UAV spraying.
Collapse
Affiliation(s)
- Yanhua Meng
- Anyang Institute of Technology, Anyang, Henan Province, China
| | - Qiufang Wu
- Anyang Institute of Technology, Anyang, Henan Province, China
- Anyang Wheat Breeding Engineering Research Centre Research Room, Anyang, Henan Province, China
| | - Hanxue Zhou
- Anyang Quanfeng Biotechnology Co., Ltd, Anyang, Henan Province, China
| | - Hongyan Hu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan Province, China
| |
Collapse
|
11
|
Davidson KJ, Lamour J, McPherran A, Rogers A, Serbin SP. Seasonal trends in leaf-level photosynthetic capacity and water use efficiency in a North American Eastern deciduous forest and their impact on canopy-scale gas exchange. THE NEW PHYTOLOGIST 2023; 240:138-156. [PMID: 37475146 DOI: 10.1111/nph.19137] [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: 12/16/2022] [Accepted: 06/24/2023] [Indexed: 07/22/2023]
Abstract
Vegetative transpiration (E) and photosynthetic carbon assimilation (A) are known to be seasonally dynamic, with changes in their ratio determining the marginal water use efficiency (WUE). Despite an understanding that stomata play a mechanistic role in regulating WUE, it is still unclear how stomatal and nonstomatal processes influence change in WUE over the course of the growing season. As a result, limited understanding of the primary physiological drivers of seasonal dynamics of canopy WUE remains one of the largest uncertainties in earth system model projections of carbon and water exchange in temperate deciduous forest ecosystems. We investigated seasonal patterns in leaf-level physiological, hydraulic, and anatomical properties, including the seasonal progress of the stomatal slope parameter (g1 ; inversely proportional to WUE) and the maximum carboxylation rate (Vcmax ). Vcmax and g1 were seasonally variable; however, their patterns were not temporally synchronized. g1 generally showed an increasing trend until late in the season, while Vcmax peaked during the midsummer months. Seasonal progression of Vcmax was primarily driven by changes in leaf structural, and anatomical characteristics, while seasonal changes in g1 were most strongly related to changes in Vcmax and leaf hydraulics. Using a seasonally variable Vcmax and g1 to parameterize a canopy-scale gas exchange model increased seasonally aggregated A and E by 3% and 16%, respectively.
Collapse
Affiliation(s)
- Kenneth J Davidson
- Department of Environmental and Climate Sciences, Brookhaven National Laboratory, Upton, NY, 11973, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Julien Lamour
- Department of Environmental and Climate Sciences, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Anna McPherran
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Alistair Rogers
- Department of Environmental and Climate Sciences, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Shawn P Serbin
- Department of Environmental and Climate Sciences, Brookhaven National Laboratory, Upton, NY, 11973, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, 11794, USA
| |
Collapse
|
12
|
Márquez DA, Stuart-Williams H, Cernusak LA, Farquhar GD. Assessing the CO 2 concentration at the surface of photosynthetic mesophyll cells. THE NEW PHYTOLOGIST 2023; 238:1446-1460. [PMID: 36751879 DOI: 10.1111/nph.18784] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
We present a robust estimation of the CO2 concentration at the surface of photosynthetic mesophyll cells (cw ), applicable under reasonable assumptions of assimilation distribution within the leaf. We used Capsicum annuum, Helianthus annuus and Gossypium hirsutumas model plants for our experiments. We introduce calculations to estimate cw using independent adaxial and abaxial gas exchange measurements, and accounting for the mesophyll airspace resistances. The cw was lower than adaxial and abaxial estimated intercellular CO2 concentrations (ci ). Differences between cw and the ci of each surface were usually larger than 10 μmol mol-1 . Differences between adaxial and abaxial ci ranged from a few μmol mol-1 to almost 50 μmol mol-1 , where the largest differences were found at high air saturation deficits (ASD). Differences between adaxial and abaxial ci and the ci estimated by mixing both fluxes ranged from -30 to +20 μmol mol-1 , where the largest differences were found under high ASD or high ambient CO2 concentrations. Accounting for cw improves the information that can be extracted from gas exchange experiments, allowing a more detailed description of the CO2 and water vapor gradients within the leaf.
Collapse
Affiliation(s)
- Diego A Márquez
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Hilary Stuart-Williams
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| |
Collapse
|
13
|
Corrigendum. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:719-721. [PMID: 37042332 DOI: 10.1111/tpj.16187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
|
14
|
Garen JC, Branch HA, Borrego I, Blonder B, Stinziano JR, Michaletz ST. Gas exchange analysers exhibit large measurement error driven by internal thermal gradients. THE NEW PHYTOLOGIST 2022; 236:369-384. [PMID: 35762843 DOI: 10.1111/nph.18347] [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: 04/05/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
Portable gas exchange analysers provide critical data for understanding plant-atmosphere carbon and water fluxes, and for parameterising Earth system models that forecast climate change effects and feedbacks. We characterised temperature measurement errors in the Li-Cor LI-6400XT and LI-6800, and estimated downstream errors in derived quantities, including stomatal conductance (gsw ) and leaf intercellular CO2 concentration (Ci ). The LI-6400XT exhibited air temperature errors (differences between reported air temperature and air temperature measured near the leaf) up to 7.2°C, leaf temperature errors up to 5.3°C, and relative errors in gsw and Ci that increased as temperatures departed from ambient. This caused errors in leaf-to-air temperature relationships, assimilation-temperature curves and CO2 response curves. Temperature dependencies of maximum Rubisco carboxylation rate (Vcmax ) and maximum RuBP regeneration rate (Jmax ) showed errors of 12% and 35%, respectively. These errors are likely to be idiosyncratic and may differ among machines and environmental conditions. The LI-6800 exhibited much smaller errors. Earth system model predictions may be erroneous, as much of their parametrisation data were measured on the LI-6400XT system, depending on the methods used. We make recommendations for minimising errors and correcting data in the LI-6400XT. We also recommend transitioning to the LI-6800 for future data collection.
Collapse
Affiliation(s)
- Josef C Garen
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Haley A Branch
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Isaac Borrego
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Benjamin Blonder
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | | | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| |
Collapse
|
15
|
Wong SC, Canny MJ, Holloway-Phillips M, Stuart-Williams H, Cernusak LA, Márquez DA, Farquhar GD. Humidity gradients in the air spaces of leaves. NATURE PLANTS 2022; 8:971-978. [PMID: 35941216 DOI: 10.1038/s41477-022-01202-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
Stomata are orifices that connect the drier atmosphere with the interconnected network of more humid air spaces that surround the cells within a leaf. Accurate values of the humidities inside the substomatal cavity, wi, and in the air, wa, are needed to estimate stomatal conductance and the CO2 concentration in the internal air spaces of leaves. Both are vital factors in the understanding of plant physiology and climate, ecological and crop systems. However, there is no easy way to measure wi directly. Out of necessity, wi has been taken as the saturation water vapour concentration at leaf temperature, wsat, and applied to the whole leaf intercellular air spaces. We explored the occurrence of unsaturation by examining gas exchange of leaves exposed to various magnitudes of wsat - wa, or Δw, using a double-sided, clamp-on chamber, and estimated degrees of unsaturation from the gradient of CO2 across the leaf that was required to sustain the rate of CO2 assimilation through the upper surface. The relative humidity in the substomatal cavities dropped to about 97% under mild Δw and as dry as around 80% when Δw was large. Measurements of the diffusion of noble gases across the leaf indicated that there were still regions of near 100% humidity distal from the stomatal pores. We suggest that as Δw increases, the saturation edge retreats into the intercellular air spaces, accompanied by the progressive closure of mesophyll aquaporins to maintain the cytosolic water potential.
Collapse
Affiliation(s)
- Suan Chin Wong
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Martin J Canny
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Meisha Holloway-Phillips
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- Physiological Plant Ecology Group, Department of Environmental Sciences-Botany, University of Basel, Basel, Switzerland
| | - Hilary Stuart-Williams
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Diego A Márquez
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Graham D Farquhar
- Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
| |
Collapse
|
16
|
Struik PC, Driever SM. Intriguing correlations between leaf architecture and intrinsic water-use efficiency enable selective breeding to mitigate climate challenges. PLANT, CELL & ENVIRONMENT 2022; 45:1607-1611. [PMID: 35274305 PMCID: PMC9313581 DOI: 10.1111/pce.14305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/25/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Paul Christiaan Struik
- Centre for Crop Systems AnalysisWageningen University and ResearchWageningenThe Netherlands
| | - Steven Michiel Driever
- Centre for Crop Systems AnalysisWageningen University and ResearchWageningenThe Netherlands
| |
Collapse
|
17
|
Lamour J, Davidson KJ, Ely KS, Le Moguédec G, Leakey ADB, Li Q, Serbin SP, Rogers A. An improved representation of the relationship between photosynthesis and stomatal conductance leads to more stable estimation of conductance parameters and improves the goodness-of-fit across diverse data sets. GLOBAL CHANGE BIOLOGY 2022; 28:3537-3556. [PMID: 35090072 DOI: 10.1111/gcb.16103] [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] [Received: 06/30/2021] [Revised: 01/17/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Stomata play a central role in surface-atmosphere exchange by controlling the flux of water and CO2 between the leaf and the atmosphere. Representation of stomatal conductance (gsw ) is therefore an essential component of models that seek to simulate water and CO2 exchange in plants and ecosystems. For given environmental conditions at the leaf surface (CO2 concentration and vapor pressure deficit or relative humidity), models typically assume a linear relationship between gsw and photosynthetic CO2 assimilation (A). However, measurement of leaf-level gsw response curves to changes in A are rare, particularly in the tropics, resulting in only limited data to evaluate this key assumption. Here, we measured the response of gsw and A to irradiance in six tropical species at different leaf phenological stages. We showed that the relationship between gsw and A was not linear, challenging the key assumption upon which optimality theory is based-that the marginal cost of water gain is constant. Our data showed that increasing A resulted in a small increase in gsw at low irradiance, but a much larger increase at high irradiance. We reformulated the popular Unified Stomatal Optimization (USO) model to account for this phenomenon and to enable consistent estimation of the key conductance parameters g0 and g1 . Our modification of the USO model improved the goodness-of-fit and reduced bias, enabling robust estimation of conductance parameters at any irradiance. In addition, our modification revealed previously undetectable relationships between the stomatal slope parameter g1 and other leaf traits. We also observed nonlinear behavior between A and gsw in independent data sets that included data collected from attached and detached leaves, and from plants grown at elevated CO2 concentration. We propose that this empirical modification of the USO model can improve the measurement of gsw parameters and the estimation of plant and ecosystem-scale water and CO2 fluxes.
Collapse
Affiliation(s)
- Julien Lamour
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Kenneth J Davidson
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Kim S Ely
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Gilles Le Moguédec
- AMAP, Université Montpellier, INRAE, Cirad CNRS, IRD, Montpellier, France
| | - Andrew D B Leakey
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Qianyu Li
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Shawn P Serbin
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Alistair Rogers
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, New York, USA
| |
Collapse
|
18
|
Giles AL, Rowland L, Bittencourt PRL, Bartholomew DC, Coughlin I, Costa PB, Domingues T, Miatto RC, Barros FV, Ferreira LV, Groenendijk P, Oliveira AAR, da Costa ACL, Meir P, Mencuccini M, Oliveira RS. Small understorey trees have greater capacity than canopy trees to adjust hydraulic traits following prolonged experimental drought in a tropical forest. TREE PHYSIOLOGY 2022; 42:537-556. [PMID: 34508606 DOI: 10.1093/treephys/tpab121] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Future climate change predictions for tropical forests highlight increased frequency and intensity of extreme drought events. However, it remains unclear whether large and small trees have differential strategies to tolerate drought due to the different niches they occupy. The future of tropical forests is ultimately dependent on the capacity of small trees (<10 cm in diameter) to adjust their hydraulic system to tolerate drought. To address this question, we evaluated whether the drought tolerance of neotropical small trees can adjust to experimental water stress and was different from tall trees. We measured multiple drought resistance-related hydraulic traits across nine common neotropical genera at the world's longest-running tropical forest throughfall-exclusion experiment and compared their responses with surviving large canopy trees. Small understorey trees in both the control and the throughfall-exclusion treatment had lower minimum stomatal conductance and maximum hydraulic leaf-specific conductivity relative to large trees of the same genera, as well as a greater hydraulic safety margin (HSM), percentage loss of conductivity and embolism resistance, demonstrating that they occupy a distinct hydraulic niche. Surprisingly, in response to the drought treatment, small trees increased specific hydraulic conductivity by 56.3% and leaf:sapwood area ratio by 45.6%. The greater HSM of small understorey trees relative to large canopy trees likely enabled them to adjust other aspects of their hydraulic systems to increase hydraulic conductivity and take advantage of increases in light availability in the understorey resulting from the drought-induced mortality of canopy trees. Our results demonstrate that differences in hydraulic strategies between small understorey and large canopy trees drive hydraulic niche segregation. Small understorey trees can adjust their hydraulic systems in response to changes in water and light availability, indicating that natural regeneration of tropical forests following long-term drought may be possible.
Collapse
Affiliation(s)
- A L Giles
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - L Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - P R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - D C Bartholomew
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - I Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
| | - P B Costa
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - T Domingues
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - R C Miatto
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - F V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - L V Ferreira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - P Groenendijk
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - A A R Oliveira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - A C L da Costa
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - P Meir
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
- School of GeoSciences, University of Edinburgh, Drummond St Edinburgh EH9 3FF, UK
| | - M Mencuccini
- CREAF, Campus UAB, Edifici C Campus de Bellaterra Cerdanyola del Vallés 08193, Spain
- ICREA, Passeig de Lluís Companys, 23, Barcelona 08010, Spain
| | - R S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| |
Collapse
|
19
|
Márquez DA, Stuart-Williams H, Farquhar GD, Busch FA. Cuticular conductance of adaxial and abaxial leaf surfaces and its relation to minimum leaf surface conductance. THE NEW PHYTOLOGIST 2022; 233:156-168. [PMID: 34192346 DOI: 10.1111/nph.17588] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Cuticular conductance to water (gcw ) is difficult to quantify for stomatous surfaces due to the complexity of separating cuticular and stomatal transpiration, and additional complications arise for determining adaxial and abaxial gcw . This has led to the neglect of gcw as a separate parameter in most common gas exchange measurements. Here, we describe a simple technique to simultaneously estimate adaxial and abaxial values of gcw , tested in two amphistomatous plant species. What we term the 'Red-Light method' is used to estimate gcw from gas exchange measurements and a known CO2 concentration inside the leaf during photosynthetic induction under red light. We provide an easy-to-use web application to assist with the calculation of gcw . While adaxial and abaxial gcw varies significantly between leaves of the same species we found that the ratio of adaxial/abaxial gcw (γn ) is stable within a plant species. This has implications for use of generic values of gcw when analysing gas exchange data. The Red-Light method can be used to estimate total cuticular conductance (gcw-T ) accurately with the most common setup of gas exchange instruments, i.e. a chamber mixing the adaxial and abaxial gases, allowing for a wide application of this technique.
Collapse
Affiliation(s)
- Diego A Márquez
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Hilary Stuart-Williams
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Graham D Farquhar
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Florian A Busch
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, B15 2TT, UK
| |
Collapse
|
20
|
Cernusak LA, De Kauwe MG. Red light shines a path forward on leaf minimum conductance. THE NEW PHYTOLOGIST 2022; 233:5-7. [PMID: 34714941 DOI: 10.1111/nph.17794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Martin G De Kauwe
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| |
Collapse
|
21
|
Johnson KM, Lucani C, Brodribb TJ. In vivo monitoring of drought-induced embolism in Callitris rhomboidea trees reveals wide variation in branchlet vulnerability and high resistance to tissue death. THE NEW PHYTOLOGIST 2022; 233:207-218. [PMID: 34625973 DOI: 10.1111/nph.17786] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Damage to the plant water transport system through xylem cavitation is known to be a driver of plant death in drought conditions. However, a lack of techniques to continuously monitor xylem embolism in whole plants in vivo has hampered our ability to investigate both how this damage propagates and the possible mechanistic link between xylem damage and tissue death. Using optical and fluorescence sensors, we monitored drought-induced xylem embolism accumulation and photosynthetic damage in vivo throughout the canopy of a drought-resistant conifer, Callitris rhomboidea, during drought treatments of c. 1 month duration. We show that drought-induced damage to the xylem can be monitored in vivo in whole trees during extended periods of water stress. Under these conditions, vulnerability of the xylem to cavitation varied widely among branchlets, with photosynthetic damage only recorded once > 90% of the xylem was cavitated. The variation in branchlet vulnerability has important implications for understanding how trees like C. rhomboidea survive drought, and the high resistance of branchlets to tissue damage points to runaway cavitation as a likely driver of tissue death in C. rhomboidea branch tips.
Collapse
Affiliation(s)
- Kate M Johnson
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Christopher Lucani
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy J Brodribb
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| |
Collapse
|
22
|
Lamour J, Davidson KJ, Ely KS, Li Q, Serbin SP, Rogers A. New calculations for photosynthesis measurement systems: what's the impact for physiologists and modelers? THE NEW PHYTOLOGIST 2022; 233:592-598. [PMID: 34605019 DOI: 10.1111/nph.17762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/13/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Julien Lamour
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Kenneth J Davidson
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, 11794-5245, USA
| | - Kim S Ely
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Qianyu Li
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Shawn P Serbin
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Alistair Rogers
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| |
Collapse
|
23
|
Tredenick EC, Farquhar GD. Dynamics of moisture diffusion and adsorption in plant cuticles including the role of cellulose. Nat Commun 2021; 12:5042. [PMID: 34413297 PMCID: PMC8377085 DOI: 10.1038/s41467-021-25225-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
Food production must increase significantly to sustain a growing global population. Reducing plant water loss may help achieve this goal and is especially relevant in a time of climate change. The plant cuticle defends leaves against drought, and so understanding water movement through the cuticle could help future proof our crops and better understand native ecology. Here, via mathematical modelling, we identify mechanistic properties of water movement in cuticles. We model water sorption in astomatous isolated cuticles, utilising three separate pathways of cellulose, aqueous pores and lipophilic. The model compares well to data both over time and humidity gradients. Sensitivity analysis shows that the grouping of parameters influencing plant species variations has the largest effect on sorption, those influencing cellulose are very influential, and aqueous pores less so but still relevant. Cellulose plays a significant role in diffusion and adsorption in the cuticle and the cuticle surfaces.
Collapse
Affiliation(s)
- E C Tredenick
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT, Australia.
| | - G D Farquhar
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| |
Collapse
|