51
|
Jerszurki D, Sperling O, Parthasarathi T, Lichston JE, Yaaran A, Moshelion M, Rachmilevitch S, Lazarovitch N. Wide vessels sustain marginal transpiration flux and do not optimize inefficient gas exchange activity under impaired hydraulic control and salinity. PHYSIOLOGIA PLANTARUM 2020; 170:60-74. [PMID: 32303105 DOI: 10.1111/ppl.13107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 04/03/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
Plants optimize water use and carbon assimilation via transient regulation of stomata resistance and by limiting hydraulic conductivity in a long-term response of xylem anatomy. We postulated that without effective hydraulic regulation plants would permanently restrain water loss and photosynthetic productivity under salt stress conditions. We compared wild-type tomatoes to a transgenic type (TT) with impaired stomatal control. Gas exchange activity, biomass, starch content, leaf area and root traits, mineral composition and main stems xylem anatomy and hydraulic conductivity were analyzed in plants exposed to salinities of 1 and 4 dS m-1 over 60 days. As the xylem cannot easily readjust to different environmental conditions, shifts in its anatomy and the permanent effect on plant hydraulic conductivity kept transpiration at lower levels under unstressed conditions and maintained it under salt-stress, while sustaining higher but inefficient assimilation rates, leading to starch accumulation and decreased plant biomass, leaf and root area and root length. Narrow conduits in unstressed TT plants were related to permanent restrain of hydraulic conductivity and plant transpiration. Under salinity, TT plants followed the atmospheric water demand, sustained similar transpiration rate from unstressed to salt-stressed conditions and possibly maintained hydraulic integrity, due to likely impaired hydraulic regulation, wider conduits and higher hydraulic conductivity. The accumulation of salts and starch in the TT plants was a strong evidence of salinity tolerance via osmotic regulation, also thought to help to maintain the assimilation rates and transpiration flux under salinity, although it was not translated into higher growth.
Collapse
Affiliation(s)
- Daniela Jerszurki
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Or Sperling
- Institute of Plant Sciences, Agricultural Research Organization (ARO), Gilat Research Center, Israel
| | - Theivasigamani Parthasarathi
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | | | - Adi Yaaran
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food & Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Menachem Moshelion
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food & Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Shimon Rachmilevitch
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Naftali Lazarovitch
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| |
Collapse
|
52
|
Skelton RP. Quantifying plant hydraulic function becomes a tall order. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3927-3929. [PMID: 32628768 PMCID: PMC7337181 DOI: 10.1093/jxb/eraa240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This article comments on:
Soriano D, Echeverría A, Anfodillo T, Rosell JA, Olson ME. 2020. Hydraulic traits vary following tip-to-base conduit widening in vascular plants. Journal of Experimental Botany 71, 4232–4242.
Collapse
Affiliation(s)
- Robert P Skelton
- South African Environmental Observation Network, Fynbos Node, Newlands, Cape Town, South Africa
| |
Collapse
|
53
|
Soriano D, Echeverría A, Anfodillo T, Rosell JA, Olson ME. Hydraulic traits vary as the result of tip-to-base conduit widening in vascular plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4232-4242. [PMID: 32219309 DOI: 10.1093/jxb/eraa157] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 03/26/2020] [Indexed: 06/10/2023]
Abstract
Plant hydraulic traits are essential metrics for characterizing variation in plant function, but they vary markedly with plant size and position in a plant. We explore the potential effect of conduit widening on variation in hydraulic traits along the stem. We examined three species that differ in conduit diameter at the stem base for a given height (Moringa oleifera, Casimiroa edulis, and Pinus ayacahuite). We made anatomical and hydraulic measurements at different distances from the stem tip, constructed vulnerability curves, and examined the safety-efficiency trade-off with height-standardized data. Our results showed that segment-specific hydraulic resistance varied predictably along the stem, paralleling changes in mean conduit diameter and total number of conduits. The Huber value and leaf specific conductivity also varied depending on the sampling point. Vulnerability curves were markedly less noisy with height standardization, making the vulnerability-efficiency trade-off clearer. Because conduits widen predictably along the stem, taking height and distance from the tip into account provides a way of enhancing comparability and interpretation of hydraulic traits. Our results suggest the need for rethinking hydraulic sampling for comparing plant functional differences and strategies across individuals.
Collapse
Affiliation(s)
- Diana Soriano
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
| | - Alberto Echeverría
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD), Italy
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, México
| | - Mark E Olson
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
| |
Collapse
|
54
|
O’Connell E, Savage J. Extended leaf phenology has limited benefits for invasive species growing at northern latitudes. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02301-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
55
|
García-Cervigón AI, Fajardo A, Caetano-Sánchez C, Camarero JJ, Olano JM. Xylem anatomy needs to change, so that conductivity can stay the same: xylem adjustments across elevation and latitude in Nothofagus pumilio. ANNALS OF BOTANY 2020; 125:1101-1112. [PMID: 32173741 PMCID: PMC7262467 DOI: 10.1093/aob/mcaa042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/10/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND AIMS Plants have the potential to adjust the configuration of their hydraulic system to maintain its function across spatial and temporal gradients. Species with wide environmental niches provide an ideal framework to assess intraspecific xylem adjustments to contrasting climates. We aimed to assess how xylem structure in the widespread species Nothofagus pumilio varies across combined gradients of temperature and moisture, and to what extent within-individual variation contributes to population responses across environmental gradients. METHODS We characterized xylem configuration in branches of N. pumilio trees at five sites across an 18° latitudinal gradient in the Chilean Andes, sampling at four elevations per site. We measured vessel area, vessel density and the degree of vessel grouping. We also obtained vessel diameter distributions and estimated the xylem-specific hydraulic conductivity. Xylem traits were studied in the last five growth rings to account for within-individual variation. KEY RESULTS Xylem traits responded to changes in temperature and moisture, but also to their combination. Reductions in vessel diameter and increases in vessel density suggested increased safety levels with lower temperatures at higher elevation. Vessel grouping also increased under cold and dry conditions, but changes in vessel diameter distributions across the elevational gradient were site-specific. Interestingly, the estimated xylem-specific hydraulic conductivity remained constant across elevation and latitude, and an overwhelming proportion of the variance of xylem traits was due to within-individual responses to year-to-year climatic fluctuations, rather than to site conditions. CONCLUSIONS Despite conspicuous adjustments, xylem traits were coordinated to maintain a constant hydraulic function under a wide range of conditions. This, combined with the within-individual capacity for responding to year-to-year climatic variations, may have the potential to increase forest resilience against future environmental changes.
Collapse
Affiliation(s)
- Ana I García-Cervigón
- Departamento de Biología y Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Camino Baguales s/n, Coyhaique, Chile
| | - Cristina Caetano-Sánchez
- Departamento de Biología-IVAGRO, Universidad de Cádiz, Campus Río San Pedro s/n, Puerto Real, Spain
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana, Zaragoza, Spain and
| | - José Miguel Olano
- iuFOR-EiFAB, Universidad de Valladolid, Campus Duques de Soria, Soria, Spain
| |
Collapse
|
56
|
Olson M, Rosell JA, Martínez‐Pérez C, León‐Gómez C, Fajardo A, Isnard S, Cervantes‐Alcayde MA, Echeverría A, Figueroa‐Abundiz VA, Segovia‐Rivas A, Trueba S, Vázquez‐Segovia K. Xylem vessel‐diameter–shoot‐length scaling: ecological significance of porosity types and other traits. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1410] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mark Olson
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Julieta A. Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad Instituto de Ecología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Cecilia Martínez‐Pérez
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Calixto León‐Gómez
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Camino Baguales s/n Coyhaique 5951601 Chile
| | - Sandrine Isnard
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Centre de Coopération Internationale en Recherche Agronomique pour le Développement Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique Université de Montpellier Montpellier 34398 France
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Herbier de Nouvelle‐Caledonia Nouméa 98848 New Caledonia
| | - María Angélica Cervantes‐Alcayde
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alberto Echeverría
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Víctor A. Figueroa‐Abundiz
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alí Segovia‐Rivas
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Santiago Trueba
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Centre de Coopération Internationale en Recherche Agronomique pour le Développement Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique Université de Montpellier Montpellier 34398 France
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Herbier de Nouvelle‐Caledonia Nouméa 98848 New Caledonia
- School of Forestry & Environmental Studies Yale University New Haven Connecticut 06511 USA
| | - Karen Vázquez‐Segovia
- Laboratorio Nacional de Ciencias de la Sostenibilidad Instituto de Ecología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| |
Collapse
|
57
|
Maruta E, Kubota M, Ikeda T. Effects of xylem embolism on the winter survival of Abies veitchii shoots in an upper subalpine region of central Japan. Sci Rep 2020; 10:6594. [PMID: 32313053 PMCID: PMC7171099 DOI: 10.1038/s41598-020-62651-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/11/2020] [Indexed: 11/09/2022] Open
Abstract
At high elevations, winter climatic conditions frequently cause excessive drought stress, which can induce embolism in conifer trees. We investigated the formation and repair of winter embolism in subalpine fir (Abies veitchii) growing near the timberline. We found a complete loss in xylem conductivity [100% percent loss of conductivity (PLC)] at the wind-exposed site (W+) and 40% PLC at the wind-protected site (W−). A PLC of 100% was far above the embolism rate expected from the drought-induced vulnerability analysis in the laboratory. At the W+ site, a PLC of 100% was maintained until May; this suddenly decreased to a negligible value in June, whereas the recovery at the W− site started in late winter and proceeded stepwise. The contrast between the two sites may have occurred because of the different underlying mechanisms of winter embolism. If most tracheids in the xylem of 100% PLC are air-filled, it will be difficult to refill quickly. However, embolism caused by pit aspiration could be restored rapidly, because aspirated pits isolate tracheids from each other and prevent the spread of cavitation. Although severe embolism may cause frost damage of needles, it may have a role in holding water within the stem.
Collapse
Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8520, Japan. .,Department of Biological Science, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan.
| | - Mitsumasa Kubota
- Department of Bioresource Science, Faculty of Agriculture, Shizuoka University, 836 Oya, Surugaku, Shizuoka, 422-8529, Japan.,Daitou Techuno Green Inc., 1-2-3 Haramachida, Machida, Tokyo, 194-0013, Japan
| | - Takefumi Ikeda
- Department of Forest Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto, 606-8522, Japan
| |
Collapse
|
58
|
Variation in Stem Xylem Traits is Related to Differentiation of Upper Limits of Tree Species along an Elevational Gradient. FORESTS 2020. [DOI: 10.3390/f11030349] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The distribution limits of many plants are dictated by environmental conditions and species’ functional traits. While many studies have evaluated how plant distribution is driven by environmental conditions, there are not many studies investigating xylem vessel properties with altitude, and whether these traits correlate with altitudinal distribution of tree. Here, we investigated the upper limits of distribution for ten deciduous broadleaf tree species from three temperate montane forest communities along a large elevational gradient on the north-facing slope of Changbai Mountain in Northeast China. We measured stem xylem traits associated with a species’ ability to transport water and resist freezing-induced cavitation that theoretically represent important adaptations to changes in climatic conditions along the elevational gradient. Hydraulically weighted vessel diameter (Dh) was negatively correlated with with the upper limit across the ten studied tree species; however, the correlation seems to be driven by the large differences between ring- and diffuse-porous tree species groups. The ring-porous tree species (e.g., Fraxinus mandshurica Rupr., Maackia amurensis Rupr. et Maxim., and Phellodendron amurense Rupr.) had considerably wider vessels than the diffuse-porous species and were all limited to low-elevation communities. The coefficient of variation (CV) for Dh was 0.53 among the 10 studied species, while the intraspecific analysis showed that the highest CV was only 0.22 among the 10 species. We found no evidence of a relationship between Dh and the upper limits across the seven diffuse-porous species. In contrast to elevation, hydraulic-related xylem traits had no clear patterns of change with precipitation, indicating that hydraulic functionality was largely decoupled from the influences of precipitation in the study area. This finding suggests that xylem traits are associated with altitudinal limits of species distribution, which is mostly evidenced by the contrasts between ring- and diffuse-porous species in xylem anatomy and their altitudinal distributions.
Collapse
|
59
|
He P, Gleason SM, Wright IJ, Weng E, Liu H, Zhu S, Lu M, Luo Q, Li R, Wu G, Yan E, Song Y, Mi X, Hao G, Reich PB, Wang Y, Ellsworth DS, Ye Q. Growing-season temperature and precipitation are independent drivers of global variation in xylem hydraulic conductivity. GLOBAL CHANGE BIOLOGY 2020; 26:1833-1841. [PMID: 31749261 DOI: 10.1111/gcb.14929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Stem xylem-specific hydraulic conductivity (KS ) represents the potential for plant water transport normalized by xylem cross section, length, and driving force. Variation in KS has implications for plant transpiration and photosynthesis, growth and survival, and also the geographic distribution of species. Clarifying the global-scale patterns of KS and its major drivers is needed to achieve a better understanding of how plants adapt to different environmental conditions, particularly under climate change scenarios. Here, we compiled a xylem hydraulics dataset with 1,186 species-at-site combinations (975 woody species representing 146 families, from 199 sites worldwide), and investigated how KS varied with climatic variables, plant functional types, and biomes. Growing-season temperature and growing-season precipitation drove global variation in KS independently. Both the mean and the variation in KS were highest in the warm and wet tropical regions, and lower in cold and dry regions, such as tundra and desert biomes. Our results suggest that future warming and redistribution of seasonal precipitation may have a significant impact on species functional diversity, and is likely to be particularly important in regions becoming warmer or drier, such as high latitudes. This highlights an important role for KS in predicting shifts in community composition in the face of climate change.
Collapse
Affiliation(s)
- Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ensheng Weng
- Center for Climate Systems Research, Columbia University, New York, NY, USA
| | - Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Mingzhen Lu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Qi Luo
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Ronghua Li
- Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China
| | - Guilin Wu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Enrong Yan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yanjun Song
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Yingping Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- CSIRO Oceans and Atmosphere, Aspendale, Vic., Australia
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| |
Collapse
|
60
|
Dai Y, Wang L, Wan X. Frost fatigue and its spring recovery of xylem conduits in ring-porous, diffuse-porous, and coniferous species in situ. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 146:177-186. [PMID: 31756604 DOI: 10.1016/j.plaphy.2019.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Frost-induced embolism and frost fatigue are two major aspects of frost damage to xylem water transport in trees. In this study, three species of each ring-porous, diffuse-porous, and coniferous trees growing in situ were used to explore their differences in winter embolism and frost fatigue. Changes in predawn water potential, predawn native embolism, maximal specific conductivity (Kmax), and cavitation resistance (P50, xylem water potential at 50% loss of conductivity) of current-year branches were measured from autumn to spring. Maximum native embolism of late winter was near 100% for ring-porous species, approximately 80% for diffuse-porous species, and below 50% for conifers. In early spring, there was no significant reduction of native embolism until formation of new vessels in ring-porous trees, while diffuse-porous trees and conifers exhibited a reduction in native embolism before development of new xylem. There was a significant decrease in P50 of ring- and diffuse-porous species over winter; however, in May P50 was markedly reduced along with formation of new vessels. Kmax of ring- and diffuse-porous species significantly decreased from autumn to late winter. The results revealed that vulnerability to cavitation and frost fatigue was related to conduit diameter. The strategies for coping with winter embolism differed among the three wood types: in ring-porous species there was no active embolism refilling; in diffuse-porous species there was refilling associated with positive xylem pressure; and in conifers there was refilling without positive xylem pressure. New vessels could completely restore stem hydraulic conductivity but only partially restore xylem cavitation resistance in spring.
Collapse
Affiliation(s)
- Yongxin Dai
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China; College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China.
| |
Collapse
|
61
|
Dolezal J, Klimes A, Dvorsky M, Riha P, Klimesova J, Schweingruber F. Disentangling evolutionary, environmental and morphological drivers of plant anatomical adaptations to drought and cold in Himalayan graminoids. OIKOS 2019. [DOI: 10.1111/oik.06451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jiri Dolezal
- Inst. of Botany, Academy of Sciences of the Czech Republic Trebon Czech Republic
- Laboratory of Tree Ring Research, Univ. of Arizona Tucson AZ USA
| | - Adam Klimes
- Inst. of Botany, Academy of Sciences of the Czech Republic Trebon Czech Republic
- Dept of Botany, Faculty of Science, Charles Univ Praha Czech Republic
| | - Miroslav Dvorsky
- Inst. of Botany, Academy of Sciences of the Czech Republic Trebon Czech Republic
| | - Pavel Riha
- Inst. of Botany, Academy of Sciences of the Czech Republic Trebon Czech Republic
| | - Jitka Klimesova
- Inst. of Botany, Academy of Sciences of the Czech Republic Trebon Czech Republic
- Dept of Botany, Faculty of Science, Charles Univ Praha Czech Republic
| | | |
Collapse
|
62
|
Wason JW, Brodersen CR, Huggett BA. The functional implications of tracheary connections across growth rings in four northern hardwood trees. ANNALS OF BOTANY 2019; 124:297-306. [PMID: 31330537 PMCID: PMC6758585 DOI: 10.1093/aob/mcz076] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/02/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Deciduous angiosperm trees transport xylem sap through trunks and branches in vessels within annual growth rings. Utilizing previous growth rings for sap transport could increase vessel network size and redundancy but may expose new xylem to residual air embolisms in the network. Despite the important role of vessel networks in sap transport and drought resistance, our understanding of cross-ring connections within and between species is limited. METHODS We studied cross-ring connections in four temperate deciduous trees using dye staining and X-ray microcomputed tomography (microCT) to detect xylem connectivity across growth rings and quantify their impact on hydraulic conductivity. KEY RESULTS Acer rubrum and Fraxinus americana had cross-ring connections visible in microCT but only A. rubrum used previous growth rings for axial sap flow. Fagus grandifolia and Quercus rubra, however, did not have cross-ring connections. Accounting for the number of growth rings that function for axial transport improved hydraulic conductivity estimates. CONCLUSIONS These data suggest that the presence of cross-ring connections may help explain aspects of whole-tree xylem sap transport and should be considered for plant hydraulics measurements in these species and others with similar anatomy.
Collapse
Affiliation(s)
- Jay W Wason
- School of Forest Resources, University of Maine, Orono, ME, USA
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
- For correspondence. E-mail
| | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | | |
Collapse
|
63
|
Dória LC, Meijs C, Podadera DS, Del Arco M, Smets E, Delzon S, Lens F. Embolism resistance in stems of herbaceous Brassicaceae and Asteraceae is linked to differences in woodiness and precipitation. ANNALS OF BOTANY 2019; 124:1-14. [PMID: 30590483 PMCID: PMC6676380 DOI: 10.1093/aob/mcy233] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/05/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND AND AIMS Plant survival under extreme drought events has been associated with xylem vulnerability to embolism (the disruption of water transport due to air bubbles in conduits). Despite the ecological and economic importance of herbaceous species, studies focusing on hydraulic failure in herbs remain scarce. Here, we assess the vulnerability to embolism and anatomical adaptations in stems of seven herbaceous Brassicaceae species occurring in different vegetation zones of the island of Tenerife, Canary Islands, and merged them with a similar hydraulic-anatomical data set for herbaceous Asteraceae from Tenerife. METHODS Measurements of vulnerability to xylem embolism using the in situ flow centrifuge technique along with light and transmission electron microscope observations were performed in stems of the herbaceous species. We also assessed the link between embolism resistance vs. mean annual precipitation and anatomical stem characters. KEY RESULTS The herbaceous species show a 2-fold variation in stem P50 from -2.1 MPa to -4.9 MPa. Within Hirschfeldia incana and Sisymbrium orientale, there is also a significant stem P50 difference between populations growing in contrasting environments. Variation in stem P50 is mainly explained by mean annual precipitation as well as by the variation in the degree of woodiness (calculated as the proportion of lignified area per total stem area) and to a lesser extent by the thickness of intervessel pit membranes. Moreover, mean annual precipitation explains the total variance in embolism resistance and stem anatomical traits. CONCLUSIONS The degree of woodiness and thickness of intervessel pit membranes are good predictors of embolism resistance in the herbaceous Brassicaceae and Asteraceae species studied. Differences in mean annual precipitation across the sampling sites affect embolism resistance and stem anatomical characters, both being important characters determining survival and distribution of the herbaceous eudicots.
Collapse
Affiliation(s)
| | - Cynthia Meijs
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
| | | | - Marcelino Del Arco
- Department of Plant Biology (Botany), La Laguna University, La Laguna, Tenerife, Spain
| | - Erik Smets
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
| | | | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
| |
Collapse
|
64
|
Smith MS, Centinari M. Young grapevines exhibit interspecific differences in hydraulic response to freeze stress but not in recovery. PLANTA 2019; 250:495-505. [PMID: 31089803 DOI: 10.1007/s00425-019-03183-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
This study demonstrated that freeze-induced hydraulic failure varies between two Vitis species that have different xylem vessel frequency and grouping. However, seasonal recovery of young grapevines was similar between the species. Sub-freezing temperatures after budburst represent a major threat for the cultivation of fruit crops in temperate regions. Freeze stress might disrupt xylem hydraulic functionality and plant growth; however, it is unclear if hydraulic traits influence the ability of woody plants to cope with freeze stress. We investigated if a grapevine species (Vitis hybrid) with earlier budburst had anatomical traits that cause higher freeze-induced hydraulic failure but also confer a greater ability for seasonal recovery compared to a Vitis vinifera species. Two-year-old Vitis hybrid and vinifera grapevines were container-grown outdoors, assigned to either a control (n = 40) or a freeze-stressed (n = 40) treatment and exposed to a controlled-temperature (- 4 °C) freeze stress shortly after budburst. We found that the Vitis hybrid had greater stem-specific hydraulic conductivity (Ks) and was more vulnerable to freeze-induced embolism compared to the V. vinifera species, which exhibited a less efficient but safer water transport strategy. Seventy-two hours after the freeze stress, Ks of freeze-stressed V. vinifera was 77.8% higher than that of the control, indicating hydraulic recovery. While the two species did not differ in xylem vessel diameter, Vitis hybrid exhibited higher vessel frequency and percentage of vessel grouping, which could explain its higher Ks and greater freeze-induced Ks loss compared to the V. vinifera vines. While the two species varied in the short-term hydraulic response, they exhibited similar and full hydraulic and vegetative recovery by midseason, including bud freeze tolerance during the following fall and mid-winter.
Collapse
Affiliation(s)
- Maria S Smith
- Department of Plant Science, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, 44691, USA
| | - Michela Centinari
- Department of Plant Science, The Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|
65
|
Lusk CH, Grierson ERP, Laughlin DC. Large leaves in warm, moist environments confer an advantage in seedling light interception efficiency. THE NEW PHYTOLOGIST 2019; 223:1319-1327. [PMID: 30985943 DOI: 10.1111/nph.15849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/07/2019] [Indexed: 06/09/2023]
Abstract
Leaf size varies conspicuously along environmental gradients. Small leaves help plants cope with drought and frost, because of the effect of leaf size on boundary layer conductance; it is less clear what advantage large leaves confer in benign environments. We asked if large leaves give species of warm climates an advantage in seedling light interception efficiency over small-leaved species from colder environments. We measured seedling leaf, architectural and biomass distribution traits of 18 New Zealand temperate rainforest evergreens; we then used a 3-D digitiser and the Yplant program to model leaf area display and light interception. Species associated with mild climates on average had larger leaves and larger specific leaf areas (SLA) than those from cold climates, and displayed larger effective foliage areas per unit of aboveground biomass, indicating higher light interception efficiency at whole-plant level. This reflected differences in total foliage area, rather than in self-shading. Our findings advance the understanding of leaf size by showing that large leaves enable seedlings of species with highly conductive (but frost-sensitive) xylem to deploy large foliage areas without increasing self-shading. Leaf size variation along temperature gradients in humid forests may therefore reflect a trade-off between seedling light interception efficiency and susceptibility to frost.
Collapse
Affiliation(s)
- Christopher H Lusk
- Environmental Research Institute, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand
| | - Ella R P Grierson
- The New Zealand Institute for Plant & Food Research, Sandringham 1142, Auckland, New Zealand
| | - Daniel C Laughlin
- Department of Botany, University of Wyoming, Laramie, WY, 82071, USA
| |
Collapse
|
66
|
Copini P, Vergeldt FJ, Fonti P, Sass-Klaassen U, den Ouden J, Sterck F, Decuyper M, Gerkema E, Windt CW, Van As H. Magnetic resonance imaging suggests functional role of previous year vessels and fibres in ring-porous sap flow resumption. TREE PHYSIOLOGY 2019; 39:1009-1018. [PMID: 30896019 DOI: 10.1093/treephys/tpz019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/15/2019] [Indexed: 06/09/2023]
Abstract
Reactivation of axial water flow in ring-porous species is a complex process related to stem water content and developmental stage of both earlywood-vessel and leaf formation. Yet empirical evidence with non-destructive methods on the dynamics of water flow resumption in relation to these mechanisms is lacking. Here we combined in vivo magnetic resonance imaging and wood-anatomical observations to monitor the dynamic changes in stem water content and flow during spring reactivation in 4-year-old pedunculate oaks (Quercus robur L.) saplings. We found that previous year latewood vessels and current year developing earlywood vessels form a functional unit for water flow during growth resumption. During spring reactivation, water flow shifted from latewood towards the new earlywood, paralleling the formation of earlywood vessels and leaves. At leaves' full expansion, volumetric water content of previous rings drastically decreased due to the near-absence of water in fibre tissue. We conclude (i) that in ring-porous oak, latewood vessels play an important hydraulic role for bridging the transition between old and new water-conducting vessels and (ii) that fibre and parenchyma provides a place for water storage.
Collapse
Affiliation(s)
- Paul Copini
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
- Wageningen Environmental Research, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
| | - Frank J Vergeldt
- Laboratory of Biophysics and MAGNetic resonance research FacilitY (MAGNEFY), Wageningen University & Research, Postbus 8128, 6700ET Wageningen, The Netherlands
| | - Patrick Fonti
- Swiss Federal Institute for Forest Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - Ute Sass-Klaassen
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
| | - Jan den Ouden
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
| | - Mathieu Decuyper
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
- Laboratory of Geo-Information Science and Remote Sensing, Wageningen University & Research, PO Box 47, AA Wageningen, The Netherlands
| | - Edo Gerkema
- Laboratory of Biophysics and MAGNetic resonance research FacilitY (MAGNEFY), Wageningen University & Research, Postbus 8128, 6700ET Wageningen, The Netherlands
| | - Carel W Windt
- IBG-2: Plant Sciences, Institute of Bio- and Geosciences, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Henk Van As
- Laboratory of Biophysics and MAGNetic resonance research FacilitY (MAGNEFY), Wageningen University & Research, Postbus 8128, 6700ET Wageningen, The Netherlands
| |
Collapse
|
67
|
Zhang W, Jiang Z, Zhao H, Feng F, Cai J. Frost fatigue response to simulated frost drought using a centrifuge in Acer mono Maxim. PHYSIOLOGIA PLANTARUM 2019; 166:677-687. [PMID: 30136279 DOI: 10.1111/ppl.12816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/17/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
In the coldest part of winter, water uptake is blocked by the frozen soil and frozen stems known as 'frost drought' causing severe embolisms in woody plants. Frost drought in stems was simulated in a centrifuge by a synergy between freeze-thaw cycles and the different tensions induced by changing the rotation speed. Frost fatigue was defined as a reduction of embolism resistance after a freeze-thaw cycle and determined from 'vulnerability curves', which showed percent losses of conductivity vs tension (positive value) or xylem pressure (negative value). Different tensions combined with a controlled freeze-thaw cycle were induced to investigate the effects on frost resistance over the course of year. During the growing season, Acer mono Maxim. developed significant frost fatigue, and a significant positive correlation was found between frost fatigue response and exogenous tension. During the dormant season, A. mono showed very high embolism resistance to frost drought, even under a tension of 2 MPa. When the exogenous tension was increased to 3 MPa while the stem was frozen, significant frost fatigue occurred. Longer freezing times had more serious effects on frost fatigue in A. mono. A hypothesis was raised that at the same low temperature, the severer the drought (higher tension) when stems were frozen, the higher frost fatigue response would be induced.
Collapse
Affiliation(s)
- Wen Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Institute of Environment and Ecology, Shandong Normal University, Ji'nan, Shandong, 250014, China
| | - Zaimin Jiang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Han Zhao
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jing Cai
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| |
Collapse
|
68
|
Umebayashi T, Sperry JS, Smith DD, Love DM. 'Pressure fatigue': the influence of sap pressure cycles on cavitation vulnerability in Acer negundo. TREE PHYSIOLOGY 2019; 39:740-746. [PMID: 30799506 DOI: 10.1093/treephys/tpy148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 05/11/2023]
Abstract
Vulnerability-to-cavitation curves (VCs) can vary within a tree crown in relation to position or branch age. We tested the hypothesis that VC variation can arise from differential susceptibility to the number of diurnal sap pressure cycles experienced. We designed a method to distinguish between effects of cycling vs exposure time to negative pressure, and tested the influence of sap pressure cycles on cavitation vulnerability between upper and lower branches in Acer negundo L. trees using static and flow centrifuge, and air-injection methods. Branches from the upper crown had greater hydraulic conductivity and were more resistant to cavitation than branches from the lower crown. Upper branches also showed little change after exposure to 10 or 20 pressure cycles between -0.5 MPa and -2.0 MPa. Lower branches, however, showed a marked increase in vulnerability to cavitation after pressure-cycling. This result suggests that 'cavitation fatigue' can occur without the actual induction (and reversal) of cavitation as documented previously, but simply from the cycling of pressures in the sub-cavitation range. This 'pressure fatigue' may explain age-related shifts in VCs that could eventually induce dieback in suppressed branches or trees. Pressure fatigue may help explain developmental variation in hydraulic capacity of branches within individuals.
Collapse
Affiliation(s)
- Toshihiro Umebayashi
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - Duncan D Smith
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - David M Love
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| |
Collapse
|
69
|
When Short Stature Is an Asset in Trees. Trends Ecol Evol 2018; 34:193-199. [PMID: 30447938 DOI: 10.1016/j.tree.2018.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/18/2018] [Accepted: 10/23/2018] [Indexed: 11/20/2022]
Abstract
With their imposing grandeur, the small number of very tall tree species attract a disproportionate amount of scientific study. We right this bias by focusing here on the shorter trees, which often grow in the shade of the giants and many other places besides. That tall trees are so restricted in distribution indicates that there are far more habitats available for small trees. We discuss some leading candidates for the mechanisms that limit maximum plant height in any given habitat, as well as why every habitat has a range of plant sizes. At least two attributes - greater adaptation capacity and higher drought resistance - suggest that the forests of the future belong to short trees.
Collapse
|
70
|
Stewart JJ, Baker CR, Sharpes CS, Wong-Michalak ST, Polutchko SK, Adams WW, Demmig-Adams B. Effects of Foliar Redox Status on Leaf Vascular Organization Suggest Avenues for Cooptimization of Photosynthesis and Heat Tolerance. Int J Mol Sci 2018; 19:ijms19092507. [PMID: 30149544 PMCID: PMC6164678 DOI: 10.3390/ijms19092507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/19/2018] [Accepted: 08/22/2018] [Indexed: 01/23/2023] Open
Abstract
The interaction of heat stress with internal signaling networks was investigated through Arabidopsisthaliana mutants that were deficient in either tocopherols (vte1 mutant) or non-photochemical fluorescence quenching (NPQ; npq1, npq4, and npq1 npq4 mutants). Leaves of both vte1 and npq1 npq4 mutants that developed at a high temperature exhibited a significantly different leaf vascular organization compared to wild-type Col-0. Both mutants had significantly smaller water conduits (tracheary elements) of the xylem, but the total apparent foliar water-transport capacity and intrinsic photosynthetic capacity were similarly high in mutants and wild-type Col-0. This was accomplished through a combination of more numerous (albeit narrower) water conduits per vein, and a significantly greater vein density in both mutants relative to wild-type Col-0. The similarity of the phenotypes of tocopherol-deficient and NPQ-deficient mutants suggests that leaf vasculature organization is modulated by the foliar redox state. These results are evaluated in the context of interactions between redox-signaling pathways and other key regulators of plant acclimation to growth temperature, such as the C-repeat binding factor (CBF) transcription factors, several of which were upregulated in the antioxidant-deficient mutants. Possibilities for the future manipulation of the interaction between CBF and redox-signaling networks for the purpose of cooptimizing plant productivity and plant tolerance to extreme temperatures are discussed.
Collapse
Affiliation(s)
- Jared J Stewart
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
- School of Education, University of Colorado, Boulder, CO 80309-0249, USA.
| | - Christopher R Baker
- Department of Plant & Microbial Biology, University of California, Berkeley, CA 94720-3102, USA.
| | - Carlie S Sharpes
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | | | - Stephanie K Polutchko
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | - William W Adams
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | - Barbara Demmig-Adams
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| |
Collapse
|
71
|
Olson ME, Soriano D, Rosell JA, Anfodillo T, Donoghue MJ, Edwards EJ, León-Gómez C, Dawson T, Camarero Martínez JJ, Castorena M, Echeverría A, Espinosa CI, Fajardo A, Gazol A, Isnard S, Lima RS, Marcati CR, Méndez-Alonzo R. Plant height and hydraulic vulnerability to drought and cold. Proc Natl Acad Sci U S A 2018; 115:7551-7556. [PMID: 29967148 PMCID: PMC6055177 DOI: 10.1073/pnas.1721728115] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding how plants survive drought and cold is increasingly important as plants worldwide experience dieback with drought in moist places and grow taller with warming in cold ones. Crucial in plant climate adaptation are the diameters of water-transporting conduits. Sampling 537 species across climate zones dominated by angiosperms, we find that plant size is unambiguously the main driver of conduit diameter variation. And because taller plants have wider conduits, and wider conduits within species are more vulnerable to conduction-blocking embolisms, taller conspecifics should be more vulnerable than shorter ones, a prediction we confirm with a plantation experiment. As a result, maximum plant size should be short under drought and cold, which cause embolism, or increase if these pressures relax. That conduit diameter and embolism vulnerability are inseparably related to plant size helps explain why factors that interact with conduit diameter, such as drought or warming, are altering plant heights worldwide.
Collapse
Affiliation(s)
- Mark E Olson
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico;
| | - Diana Soriano
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, 35020 Legnaro (PD), Italy
| | - Michael J Donoghue
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106;
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106
| | - Calixto León-Gómez
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Todd Dawson
- Department of Integrative Biology, University of California, Berkeley, CA 94720-3140
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720-3140
| | - J Julio Camarero Martínez
- Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas, 50059 Zaragoza, Spain
| | - Matiss Castorena
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Alberto Echeverría
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Carlos I Espinosa
- Universidad Técnica Particular de Loja, San Cayetano Alto sn, Loja, Ecuador
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia Conicyt-Regional R10C1003, Universidad Austral de Chile, 5951601 Coyhaique, Chile
| | - Antonio Gazol
- Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas, 50059 Zaragoza, Spain
| | - Sandrine Isnard
- Botany and Modelling of Plant Architecture and Vegetation Joint Research Unit, Institut de Recherche pour le Développement, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier, 98800 Nouméa, New Caledonia
| | - Rivete S Lima
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, João Pessoa, 58051-900 Paraíba, Brazil
| | - Carmen R Marcati
- Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, 18603970 São Paulo, Brazil
| | - Rodrigo Méndez-Alonzo
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, 22860 Baja California, Mexico
| |
Collapse
|
72
|
Yin XH, Sterck F, Hao GY. Divergent hydraulic strategies to cope with freezing in co-occurring temperate tree species with special reference to root and stem pressure generation. THE NEW PHYTOLOGIST 2018; 219:530-541. [PMID: 29682759 DOI: 10.1111/nph.15170] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/18/2018] [Indexed: 05/23/2023]
Abstract
Some temperate tree species mitigate the negative impacts of frost-induced xylem cavitation by restoring impaired hydraulic function via positive pressures, and may therefore be more resistant to frost fatigue (the phenomenon that post-freezing xylem becomes more susceptible to hydraulic dysfunction) than nonpressure-generating species. We test this hypothesis and investigate underlying anatomical/physiological mechanisms. Using a common garden experiment, we studied key hydraulic traits and detailed xylem anatomical characteristics of 18 sympatric tree species. These species belong to three functional groups, that is, one generating both root and stem pressures (RSP), one generating only root pressure (RP), and one unable to generate such pressures (NP). The three functional groups diverged substantially in hydraulic efficiency, resistance to drought-induced cavitation, and frost fatigue resistance. Most notably, RSP and RP were more resistant to frost fatigue than NP, but this was at the cost of reduced hydraulic conductivity for RSP and reduced resistance to drought-induced cavitation for RP. Our results show that, in environments with strong frost stress: these groups diverge in hydraulic functioning following multiple trade-offs between hydraulic efficiency, resistance to drought and resistance to frost fatigue; and how differences in anatomical characteristics drive such divergence across species.
Collapse
Affiliation(s)
- Xiao-Han Yin
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, the Netherlands
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| |
Collapse
|
73
|
Gleason SM, Blackman CJ, Gleason ST, McCulloh KA, Ocheltree TW, Westoby M. Vessel scaling in evergreen angiosperm leaves conforms with Murray's law and area-filling assumptions: implications for plant size, leaf size and cold tolerance. THE NEW PHYTOLOGIST 2018; 218:1360-1370. [PMID: 29603233 DOI: 10.1111/nph.15116] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/15/2018] [Indexed: 05/26/2023]
Abstract
Water transport in leaf vasculature is a fundamental process affecting plant growth, ecological interactions and ecosystem productivity, yet the architecture of leaf vascular networks is poorly understood. Although Murray's law and the West-Brown-Enquist (WBE) theories predict convergent scaling of conduit width and number, it is not known how conduit scaling is affected by habitat aridity or temperature. We measured the scaling of leaf size, conduit width and conduit number within the leaves of 36 evergreen Angiosperms spanning a large range in aridity and temperature in eastern Australia. Scaling of conduit width and number in midribs and 2° veins did not differ across species and habitats (P > 0.786), and did not differ from that predicted by Murray's law (P = 0.151). Leaf size was strongly correlated with the hydraulic radius of petiole conduits (r2 = 0.83, P < 0.001) and did not differ among habitats (P > 0.064), nor did the scaling exponent differ significantly from that predicted by hydraulic theory (P = 0.086). The maximum radius of conduits in petioles was positively correlated with the temperature of the coldest quarter (r2 = 0.67; P < 0.001), suggesting that habitat temperature restricts the occurrence of wide-conduit species in cold habitats.
Collapse
Affiliation(s)
- Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Chris J Blackman
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Scott T Gleason
- University Corporation for Atmospheric Research (UCAR), 3300 Mitchell Lane, Boulder, CO, 80301, USA
| | - Katherine A McCulloh
- Department of Botany, University of Wisconsin - Madison, Madison, WI, 53706, USA
| | - Troy W Ocheltree
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| |
Collapse
|
74
|
Zanne AE, Pearse WD, Cornwell WK, McGlinn DJ, Wright IJ, Uyeda JC. Functional biogeography of angiosperms: life at the extremes. THE NEW PHYTOLOGIST 2018; 218:1697-1709. [PMID: 29603243 DOI: 10.1111/nph.15114] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
Nonlinear relationships between species and their environments are believed common in ecology and evolution, including during angiosperms' rise to dominance. Early angiosperms are thought of as woody evergreens restricted to warm, wet habitats. They have since expanded into numerous cold and dry places. This expansion may have included transitions across important environmental thresholds. To understand linear and nonlinear relationships between angiosperm structure and biogeographic distributions, we integrated large datasets of growth habits, conduit sizes, leaf phenologies, evolutionary histories, and environmental limits. We consider current-day patterns and develop a new evolutionary model to investigate processes that created them. The macroecological pattern was clear: herbs had lower minimum temperature and precipitation limits. In woody species, conduit sizes were smaller in evergreens and related to species' minimum temperatures. Across evolutionary timescales, our new modeling approach found conduit sizes in deciduous species decreased linearly with minimum temperature limits. By contrast, evergreen species had a sigmoidal relationship with minimum temperature limits and an inflection overlapping freezing. These results suggest freezing represented an important threshold for evergreen but not deciduous woody angiosperms. Global success of angiosperms appears tied to a small set of alternative solutions when faced with a novel environmental threshold.
Collapse
Affiliation(s)
- Amy E Zanne
- Department of Biological Sciences, George Washington University, Washington, DC, 20052, USA
| | - William D Pearse
- Ecology Center and Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - William K Cornwell
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Daniel J McGlinn
- Biology Department, College of Charleston, Charleston, SC, 29424, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Josef C Uyeda
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| |
Collapse
|
75
|
Medeiros JS, Danielson SC. Renewed interest in whole-plant physiology sheds light on the complexity of plant stress response architecture. TREE PHYSIOLOGY 2018; 38:503-506. [PMID: 29474704 DOI: 10.1093/treephys/tpy018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/25/2018] [Indexed: 06/08/2023]
|
76
|
Fernández-Pérez L, Villar-Salvador P, Martínez-Vilalta J, Toca A, Zavala MA. Distribution of pines in the Iberian Peninsula agrees with species differences in foliage frost tolerance, not with vulnerability to freezing-induced xylem embolism. TREE PHYSIOLOGY 2018; 38:507-516. [PMID: 29325114 DOI: 10.1093/treephys/tpx171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/09/2017] [Indexed: 06/07/2023]
Abstract
Drought and frosts are major determinants of plant functioning and distribution. Both stresses can cause xylem embolism and foliage damage. The objective of this study was to analyse if the distribution of six common pine species along latitudinal and altitudinal gradients in Europe is related to their interspecific differences in frost tolerance and to the physiological mechanisms underlying species-specific frost tolerance. We also evaluate if frost tolerance depends on plant water status. We studied survival to a range of freezing temperatures in 2-year-old plants and assessed the percentage loss of hydraulic conductivity (PLC) due xylem embolism formation and foliage damage determined by needle electrolyte leakage (EL) after a single frost cycle to -15 °C and over a range of predawn water potential (ψpd) values. Species experiencing cold winters in their range (Pinus nigra J.F. Arnold, Pinus sylvestris L. and Pinus uncinata Raymond ex A. DC.) had the highest frost survival rates and lowest needle EL and soluble sugar (SS) concentration. In contrast, the pines inhabiting mild or cool winter locations (especially Pinus halepensis Mill. and Pinus pinea L. and, to a lesser extent, Pinus pinaster Ait.) had the lowest frost survival and highest needle EL and SS values. Freezing-induced PLC was very low and differences among species were not related to frost damage. Reduction in ψpd decreased leaf frost damage in P. pinea and P. sylvestris, increased it in P. uncinata and had a neutral effect on the rest of the species. This study demonstrates that freezing temperatures are a major environmental driver for pine distribution and suggests that interspecific differences in leaf frost sensitivity rather than vulnerability to freezing-induced embolism or SS explain pine juvenile frost survival.
Collapse
Affiliation(s)
- Laura Fernández-Pérez
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Pedro Villar-Salvador
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Campus UAB, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Univ. Autònoma Barcelona, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Andrei Toca
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Miguel A Zavala
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| |
Collapse
|
77
|
Jacobsen AL, Valdovinos-Ayala J, Pratt RB. Functional lifespans of xylem vessels: Development, hydraulic function, and post-function of vessels in several species of woody plants. AMERICAN JOURNAL OF BOTANY 2018; 105:142-150. [PMID: 29570215 DOI: 10.1002/ajb2.1029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/31/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem vessels transition through different stages during their functional lifespan, including expansion and development of vessel elements, transition to vessel hydraulic functionality, and eventual transition to post-functionality. We used information on vessel development and function to develop a model of vessel lifespan for woody plants. METHODS We examined vessel functional lifespan using repeated anatomical sampling throughout the growing season, combined with active-xylem staining to evaluate vessel hydraulic transport functionality. These data were combined with a literature review. The transitions between vessel functional lifespans for several species are illustrated, including grapevine (Vitis vinifera L., Vitaceae), English oak (Quercus robur L., Fagaceae), American chestnut [Castanea dentata (Marshall) Borkh.; Fagaceae], and several arid and semi-arid shrub species. KEY RESULTS In intact woody plants, development and maturation of vessel elements may be gradual. Once hydraulically functional, vessel elements connect to form a vessel network that is responsible for bulk hydraulic flow through the xylem. Vessels become nonfunctional due to the formation of gas emboli. In some species and under some conditions, vessel functionality of embolized conduits may be restored through refilling. Blockages, such as tyloses, gels, or gums, indicate permanent losses in hydraulic functional capacity; however, there may be some interesting exceptions to permanent loss of functionality for gel-based blockages. CONCLUSIONS The gradual development and maturation of vessel elements in woody plants, variation in the onset of functionality between different populations of vessels throughout the growing season, and differences in the timing of vessel transitions to post-functionality are important aspects of plant hydraulic function.
Collapse
Affiliation(s)
- Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - Jessica Valdovinos-Ayala
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| |
Collapse
|
78
|
Losso A, Anfodillo T, Ganthaler A, Kofler W, Markl Y, Nardini A, Oberhuber W, Purin G, Mayr S. Robustness of xylem properties in conifers: analyses of tracheid and pit dimensions along elevational transects. TREE PHYSIOLOGY 2018; 38:212-222. [PMID: 29309674 DOI: 10.1093/treephys/tpx168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
In alpine regions, tree hydraulics are limited by low temperatures that restrict xylem growth and induce winter frost drought and freezing stress. While several studies have dealt with functional limitations, data on elevational changes in functionally relevant xylem anatomical parameters are still scarce. In wood cores of Pinus cembra L. and Picea abies (L.) Karst. trunks, harvested along five elevational transects, xylem anatomical parameters (tracheid hydraulic diameter dh, wall reinforcement (t/b)2), pit dimensions (pit aperture Da, pit membrane Dm and torus Dt diameters) and respective functional indices (torus overlap O, margo flexibility) were measured. In both species, tracheid diameters decreased and (t/b)2 increased with increasing elevation, while pit dimensions and functional indices remained rather constant (P. cembra: Dt 10.3 ± 0.2 μm, O 0.477 ± 0.005; P. abies: Dt 9.30 ± 0.18 μm, O 0.492 ± 0.005). However, dh increased with tree height following a power trajectory with an exponent of 0.21, and also pit dimensions increased with tree height (exponents: Dm 0.18; Dt 0.14; Da 0.11). Observed elevational trends in xylem structures were predominantly determined by changes in tree size. Tree height-related changes in anatomical traits showed a remarkable robustness, regardless of the distributional ranges of study species. Despite increasing stress intensities towards the timberline, no adjustment in hydraulic safety at the pit level was observed.
Collapse
Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di Padova, 35020 Legnaro, PD, Italy
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Werner Kofler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Yvonne Markl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Gerhard Purin
- Sportgymnasium Dornbirn, Messestraße 4, 6850 Dornbirn, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| |
Collapse
|
79
|
Blessing CH, Mariette A, Kaloki P, Bramley H. Profligate and conservative: water use strategies in grain legumes. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:349-369. [PMID: 29370385 DOI: 10.1093/jxb/erx415] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 10/23/2017] [Indexed: 06/07/2023]
Abstract
Yields of grain legumes are constrained by available water. Thus, it is crucial to understand traits influencing water uptake and the efficiency of using water to produce biomass. Global comparisons and comparisons at specific locations reveal that water use of different grain legumes is very similar, which indicates that water use efficiency varies over a wide range due to differences in biomass and yield. Moreover, yield increases more per millimetre of water used in cool season grain legumes than warm season species. Although greater contrasts have been observed across species and genotypes at the pot and lysimeter level, agronomic factors need to be taken into account when scaling those studies to field-level responses. Conservative water use strategies in grain legumes such as low stomatal conductance as approximated by low photosynthetic carbon isotope discrimination reduces yield potential, whereas temporal adjustments of stomatal conductance within the growing season and in response to environmental factors (such as vapour pressure deficit) helps to optimize the trade-off between carbon gain and water loss. Furthermore, improved photosynthetic capacity, reduced mesophyll conductance, reduced boundary layer, and re-fixation of respired CO2 were identified as traits that are beneficial without water deficit, but also under terminal and transient drought. Genotypic variability in some grain legume species has been observed for several traits that influence water use, water use efficiency, and yield, including root length and the temporal pattern of water use, but even more variation is expected from wild relatives. Albeit that N2 fixation decreases under drought, its impact on water use is still largely unknown, but the nitrogen source influences gas exchange and, thus, transpiration efficiency. This review concludes that conservative traits are needed under conditions of terminal drought to help maintain soil moisture until the pod-filling period, but profligate traits, if tightly regulated, are important under conditions of transient drought in order to profit from short intermittent periods of available soil moisture.
Collapse
Affiliation(s)
- Carola H Blessing
- The University of Sydney, School of Life and Environmental Sciences, Sydney Institute of Agriculture, Sydney, New South Wales, Australia
| | - Alban Mariette
- The University of Sydney, Plant Breeding Institute, Narrabri, New South Wales, Australia
- Biology Department, Université de Rennes 1, Campus de Beaulieu, Rennes Cedex, France
| | - Peter Kaloki
- The University of Sydney, School of Life and Environmental Sciences, Sydney Institute of Agriculture, Sydney, New South Wales, Australia
- The University of Sydney, Plant Breeding Institute, Narrabri, New South Wales, Australia
| | - Helen Bramley
- The University of Sydney, School of Life and Environmental Sciences, Sydney Institute of Agriculture, Sydney, New South Wales, Australia
- The University of Sydney, Plant Breeding Institute, Narrabri, New South Wales, Australia
| |
Collapse
|
80
|
California Chaparral and Its Global Significance. SPRINGER SERIES ON ENVIRONMENTAL MANAGEMENT 2018. [DOI: 10.1007/978-3-319-68303-4_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
81
|
Morris H, Gillingham MAF, Plavcová L, Gleason SM, Olson ME, Coomes DA, Fichtler E, Klepsch MM, Martínez-Cabrera HI, McGlinn DJ, Wheeler EA, Zheng J, Ziemińska K, Jansen S. Vessel diameter is related to amount and spatial arrangement of axial parenchyma in woody angiosperms. PLANT, CELL & ENVIRONMENT 2018; 41:245-260. [PMID: 29047119 DOI: 10.1111/pce.13091] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/22/2017] [Accepted: 09/28/2017] [Indexed: 05/13/2023]
Abstract
Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.
Collapse
Affiliation(s)
- Hugh Morris
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and Research, St. Gallen, 9014, Switzerland
| | - Mark A F Gillingham
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, D-89069, Ulm, Germany
| | - Lenka Plavcová
- Department of Biology, Faculty of Science, University of Hradec Králové, Rokitanského 62, 500 03, Hradec Králové, Czech Republic
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, 80526, USA
| | - Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de CU, Mexico, DF, 04510, Mexico
| | - David A Coomes
- Forest Ecology and Conservation Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Esther Fichtler
- Department of Crop Sciences, Tropical Plant Production and Agricultural Systems Modelling, Göttingen University, Grisebachstrasse 6, 37077, Göttingen, Germany
| | - Matthias M Klepsch
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | | | - Daniel J McGlinn
- Department of Biology, College of Charleston, Charleston, SC, 29424, USA
| | - Elisabeth A Wheeler
- Department of Forest Biomaterials, NC State University, Raleigh, NC, 27695-8005, USA
- North Carolina Museum of Natural Sciences, 11 West Jones St., Raleigh, NC, 27601, USA
| | - Jingming Zheng
- Zheng JingminG, College of Forestry, Beijing Forestry University, Beijing, 100083, China
| | - Kasia Ziemińska
- Arnold Arboretum of Harvard University, 1300 Centre St, Boston, MA, 02130, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| |
Collapse
|
82
|
Brodersen CR, Knipfer T, McElrone AJ. In vivo visualization of the final stages of xylem vessel refilling in grapevine (Vitis vinifera) stems. THE NEW PHYTOLOGIST 2018; 217:117-126. [PMID: 28940305 DOI: 10.1111/nph.14811] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/22/2017] [Indexed: 05/14/2023]
Abstract
Embolism removal is critical for restoring hydraulic pathways in some plants, as residual gas bubbles should expand when vessels are reconnected to the transpiration stream. Much of our understanding of embolism removal remains theoretical as a consequence of the lack of in vivo images of the process at high magnification. Here, we used in vivo X-ray micro-computed tomography (microCT) to visualize the final stages of xylem refilling in grapevine (Vitis vinifera) paired with scanning electron microscopy. Before refilling, vessel walls were covered with a surface film, but vessel perforation plate openings and intervessel pits were filled with air. Bubbles were removed from intervessel pits first, followed by bubbles within perforation plates, which hold the last volumes of air which eventually dissolve. Perforation plates were dimorphic, with more steeply angled scalariform plates in narrow diameter vessels, compared with the simple perforation plates in older secondary xylem, which may favor rapid refilling and compartmentalization of embolisms that occur in small vessels, while promoting high hydraulic conductivity in large vessels. Our study provides direct visual evidence of the spatial and temporal dynamics of the final stages of embolism removal.
Collapse
Affiliation(s)
- Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, CA, 95618, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA, 95618, USA
- Crops Pathology and Genetics Research Unit, USDA-ARS, Davis, CA, 95618, USA
| |
Collapse
|
83
|
Lintunen A, Mayr S, Salmon Y, Cochard H, Hölttä T. Drivers of apoplastic freezing in gymnosperm and angiosperm branches. Ecol Evol 2018; 8:333-343. [PMID: 29321875 PMCID: PMC5756836 DOI: 10.1002/ece3.3665] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/11/2022] Open
Abstract
It is not well understood what determines the degree of supercooling of apoplastic sap in trees, although it determines the number and duration of annual freeze-thaw cycles in a given environment. We studied the linkage between apoplastic ice nucleation temperature, tree water status, and conduit size. We used branches of 10 gymnosperms and 16 angiosperms collected from an arboretum in Helsinki (Finland) in winter and spring. Branches with lower relative water content froze at lower temperatures, and branch water content was lower in winter than in spring. A bench drying experiment with Picea abies confirmed that decreasing branch water potential decreases apoplastic ice nucleation temperature. The studied angiosperms froze on average 2.0 and 1.8°C closer to zero Celsius than the studied gymnosperms during winter and spring, respectively. This was caused by higher relative water content in angiosperms; when branches were saturated with water, apoplastic ice nucleation temperature of gymnosperms increased to slightly higher temperature than that of angiosperms. Apoplastic ice nucleation temperature in sampled branches was positively correlated with xylem conduit diameter as shown before, but saturating the branches removed the correlation. Decrease in ice nucleation temperature decreased the duration of freezing, which could have an effect on winter embolism formation via the time available for gas escape during ice propagation. The apoplastic ice nucleation temperature varied not only between branches but also within a branch between consecutive freeze-thaw cycles demonstrating the stochastic nature of ice nucleation.
Collapse
Affiliation(s)
- Anna Lintunen
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Stefan Mayr
- Institute of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Yann Salmon
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Hervé Cochard
- University of Clermont‐AuvergneClermont‐FerrandFrance
| | - Teemu Hölttä
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
| |
Collapse
|
84
|
Zhang Y, Klepsch M, Jansen S. Bordered pits in xylem of vesselless angiosperms and their possible misinterpretation as perforation plates. PLANT, CELL & ENVIRONMENT 2017; 40:2133-2146. [PMID: 28667823 DOI: 10.1111/pce.13014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
Vesselless wood represents a rare phenomenon within the angiosperms, characterizing Amborellaceae, Trochodendraceae and Winteraceae. Anatomical observations of bordered pits and their pit membranes based on light, scanning and transmission electron microscopy (SEM and TEM) are required to understand functional questions surrounding vesselless angiosperms and the potential occurrence of cryptic vessels. Interconduit pit membranes in 11 vesselless species showed a similar ultrastructure as mesophytic vessel-bearing angiosperms, with a mean thickness of 245 nm (± 53, SD; n = six species). Shrunken, damaged and aspirated pit membranes, which were 52% thinner than pit membranes in fresh samples (n = four species), occurred in all dried-and-rehydrated samples, and in fresh latewood of Tetracentron sinense and Trochodendron aralioides. SEM demonstrated that shrunken pit membranes showed artificially enlarged, > 100 nm wide pores. Moreover, perfusion experiments with stem segments of Drimys winteri showed that 20 and 50 nm colloidal gold particles only passed through 2 cm long dried-and-rehydrated segments, but not through similar sized fresh ones. These results indicate that pit membrane shrinkage is irreversible and associated with a considerable increase in pore size. Moreover, our findings suggest that pit membrane damage, which may occur in planta, could explain earlier records of vessels in vesselless angiosperms.
Collapse
Affiliation(s)
- Ya Zhang
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Matthias Klepsch
- 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
|
85
|
Jankowski A, Wyka TP, Żytkowiak R, Nihlgård B, Reich PB, Oleksyn J. Cold adaptation drives variability in needle structure and anatomy in
P
inus sylvestris
L. along a 1,900 km temperate–boreal transect. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12946] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Artur Jankowski
- General Botany LaboratoryFaculty of BiologyAdam Mickiewicz University Poznan Poland
- Institute of DendrologyPolish Academy of Sciences Kornik Poland
| | - Tomasz P. Wyka
- General Botany LaboratoryFaculty of BiologyAdam Mickiewicz University Poznan Poland
| | - Roma Żytkowiak
- Institute of DendrologyPolish Academy of Sciences Kornik Poland
| | | | - Peter B. Reich
- Hawkesbury Institute for the EnvironmentUniversity of Western Sydney Penrith NSW Australia
- Department of Forest ResourcesUniversity of Minnesota St. Paul MN USA
| | - Jacek Oleksyn
- Institute of DendrologyPolish Academy of Sciences Kornik Poland
- Department of Forest ResourcesUniversity of Minnesota St. Paul MN USA
| |
Collapse
|
86
|
Evans MJ, Morris RJ. Chemical agents transported by xylem mass flow propagate variation potentials. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:1029-1037. [PMID: 28656705 PMCID: PMC5601289 DOI: 10.1111/tpj.13624] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 05/20/2023]
Abstract
Long-distance signalling is important for coordinating plant responses to the environment. Variation potentials (VPs) are a type of long-distance electrical signal that are generated in plants in response to wounding or flaming. Unlike self-propagating action potentials, VPs can be measured beyond regions of dead or chemically treated tissue that block signal generation, suggesting a different mode of propagation. Two alternative propagation mechanisms have been proposed: movement of a chemical agent and a pressure wave through the vasculature. Variants of these two signalling mechanisms have been suggested. Here, we use simple models of the underlying physical processes to evaluate and compare these predictions against independent data. Our models suggest that chemical diffusion and pressure waves are unlikely to capture existing data with parameters that are known from other sources. The previously discarded hypothesis of mass flow in the xylem transporting a chemical agent, however, is able to reproduce experimental propagation speeds for VPs. We therefore suggest that chemical agents transported by mass flow within the xylem are more likely than a pressure wave or chemical diffusion as a VP propagation mechanism. Understanding this mode of long-distance signalling within plants is important for unravelling how plants coordinate physiological responses via cell-to-cell communication.
Collapse
Affiliation(s)
- Matthew J. Evans
- Computational and Systems BiologyCrop GeneticsJohn Innes CentreColney LaneNorwichNR4 7UHUK
| | - Richard J. Morris
- Computational and Systems BiologyCrop GeneticsJohn Innes CentreColney LaneNorwichNR4 7UHUK
| |
Collapse
|
87
|
Foster JR. Xylem traits, leaf longevity and growth phenology predict growth and mortality response to defoliation in northern temperate forests. TREE PHYSIOLOGY 2017; 37:1151-1165. [PMID: 28444382 DOI: 10.1093/treephys/tpx043] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 04/06/2017] [Indexed: 05/16/2023]
Abstract
Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but idiosyncratic measures used by defoliation studies have frustrated efforts to generalize among species. Here, I test for functional differences with published growth and mortality data from 37 studies, including 24 tree species and 11 defoliators from North America and Eurasia. I synthesized data into standardized variables suitable for numerical models and used linear mixed-effects models to test the hypotheses that responses to defoliation vary among species and functional groups. Standardized data show that defoliation responses vary in shape and degree. Growth decreased linearly or curvilinearly, least in ring-porous Quercus and deciduous conifers (by 10-40% per 100% defoliation), whereas growth of diffuse-porous hardwoods and evergreen conifers declined by 40-100%. Mortality increased exponentially with defoliation, most rapidly for evergreen conifers, then diffuse-porous, then ring-porous species and deciduous conifers (Larix). Goodness-of-fit for functional-group models was strong (R2c = 0.61-0.88), if lower than species-specific mixed-models (R2c = 0.77-0.93), providing useful alternatives when species data are lacking. These responses are consistent with functional differences in leaf longevity, wood growth phenology and NSC storage. When defoliator activity lags behind wood-growth, either because xylem-growth precedes budburst (Quercus) or defoliator activity peaks later (sawflies on Larix), impacts on annual wood-growth will always be lower. Wood-growth phenology of diffuse-porous species and evergreen conifers coincides with defoliation and responds more drastically, and lower axial NSC storage makes them more vulnerable to mortality as stress accumulates. These functional differences in response apply in general to disturbances that cause spring defoliation and provide a framework that should be incorporated into forest growth and vegetation models.
Collapse
Affiliation(s)
- Jane R Foster
- University of Wisconsin Madison, Department of Forest and Wildlife Ecology, 120 Russell Labs, 1630 Linden Dr., Madison, WI 53706-1520, USA
- University of Minnesota, Department of Forest Resources, 115 Green Hall, 1530 Cleveland Ave. N., St Paul, MN 55108, USA
| |
Collapse
|
88
|
Venturas MD, Sperry JS, Hacke UG. Plant xylem hydraulics: What we understand, current research, and future challenges. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:356-389. [PMID: 28296168 DOI: 10.1111/jipb.12534] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/09/2017] [Indexed: 05/22/2023]
Abstract
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.
Collapse
Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| |
Collapse
|
89
|
Hacke UG, Spicer R, Schreiber SG, Plavcová L. An ecophysiological and developmental perspective on variation in vessel diameter. PLANT, CELL & ENVIRONMENT 2017; 40:831-845. [PMID: 27304704 DOI: 10.1111/pce.12777] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 05/05/2023]
Abstract
Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the ecophysiological implications of variation in lumen diameter together with a summary of our current understanding of vessel development and its endogenous regulation. We analyzed inter-specific variation of the mean hydraulic vessel diameter (Dv ) across biomes, intra-specific variation of Dv under natural and controlled conditions, and intra-plant variation. We found that the Dv measured in young branches tends to stay below 30 µm in regions experiencing winter frost, whereas it is highly variable in the tropical rainforest. Within a plant, the widest vessels are often found in the trunk and in large roots; smaller diameters have been reported for leaves and small lateral roots. Dv varies in response to environmental factors and is not only a function of plant size. Despite the wealth of data on vessel diameter variation, the regulation of diameter is poorly understood. Polar auxin transport through the vascular cambium is a key regulator linking foliar and xylem development. Limited evidence suggests that auxin transport is also a determinant of vessel diameter. The role of auxin in cell expansion and in establishing longitudinal continuity during secondary growth deserve further study.
Collapse
Affiliation(s)
- Uwe G Hacke
- University of Alberta, Department of Renewable Resources, Edmonton, AB T6G 2E3, Canada
| | - Rachel Spicer
- Connecticut College, Department of Botany, New London, CT 06320, USA
| | - Stefan G Schreiber
- University of Alberta, Department of Renewable Resources, Edmonton, AB T6G 2E3, Canada
| | - Lenka Plavcová
- University of Hradec Králové, Department of Biology, Rokitanského 62, Hradec Králové, 500 03, Czech Republic
- Charles University, Department of Experimental Plant Biology, Viničná 5, Prague, 128 44, Czech Republic
| |
Collapse
|
90
|
Li M, Zheng Y, Fan R, Zhong Q, Cheng D. Scaling relationships of twig biomass allocation in Pinus hwangshanensis along an altitudinal gradient. PLoS One 2017; 12:e0178344. [PMID: 28552954 PMCID: PMC5446166 DOI: 10.1371/journal.pone.0178344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 05/11/2017] [Indexed: 11/19/2022] Open
Abstract
Understanding the response of biomass allocation in twigs (the terminal branches of current-year shoots) to environmental change is crucial for elucidating forest ecosystem carbon storage, carbon cycling, and plant life history strategies under a changing climate. On the basis of interspecies investigations of broad-leaved plants, previous studies have demonstrated that plants respond to environmental factors by allocating biomass in an allometric manner between support tissues (i.e., stems) and the leaf biomass of twigs, where the scaling exponent (i.e., slope of a log-log linear relationship, α) is constant, and the scaling constant (i.e., intercept of a log-log linear relationship, log β) varies with respect to environmental factors. However, little is known about whether the isometric scaling exponents of such biomass allocations remain invariant for single species, particularly conifers, at different altitudes and in different growing periods. In this study, we investigated how twig biomass allocation varies with elevation and period among Pinus hwangshanensis Hsia trees growing in the mountains of Southeast China. Specifically, we explored how twig stem mass, needle mass, and needle area varied throughout the growing period (early, mid-, late) and at three elevations in the Wuyi Mountains. Standardized major axis analysis was used to compare the scaling exponents and scaling constants between the biomass allocations of within-twig components. Scaling relationships between these traits differed with growing period and altitude gradient. During the different growing periods, there was an isometric scaling relationship, with a common slope of 1.0 (i.e., α ≈ 1.0), between needle mass and twig mass (the sum of the total needle mass and the stem mass), whereas there were allometric scaling relationships between the stem mass and twig mass and between the needle mass and stem mass of P. hwangshanensis. The scaling constants (log β) for needle mass vs. twig mass and for needle mass vs. stem mass increased progressively across the growing stages, whereas the scaling constants of stem mass vs. twig mass showed the opposite pattern. The scaling exponents (α) of needle area with respect to needle biomass increased significantly with growing period, changing from an allometric relationship (i.e., α < 1.0) during the early growing period to a nearly isometric relationship (i.e., α ≈ 1.0) during the late growing period. This change possibly reflects the functional adaptation of twigs in different growing periods to meet their specific reproductive or survival needs. At different points along the altitudinal gradient, the relationships among needle mass, twig mass, and stem mass were all isometric (i.e., α ≈ 1.0). Moreover, significant differences were found in scaling constants (log β) along the altitudinal gradient, such that species had a smaller stem biomass but a relatively larger needle mass at low altitude. In addition, the scaling exponents remained numerically invariant among all three altitudes, with a common slope of 0.8, suggesting that needle area failed to keep pace with the increasing needle mass at different altitudes. Our results indicated that the twig biomass allocation pattern was significantly influenced by altitude and growing period, which reflects the functional adaptation of twigs to meet their specific survival needs under different climatic conditions.
Collapse
Affiliation(s)
- Man Li
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, Fujian Province, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, Fujian Province, China
| | - Yuan Zheng
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, Fujian Province, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, Fujian Province, China
| | - RuiRui Fan
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, Fujian Province, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, Fujian Province, China
| | - QuanLin Zhong
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, Fujian Province, China
| | - DongLiang Cheng
- Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, Fujian Province, China
- Key Laboratory of Humid Subtropical Eco-geographical Process, Ministry of Education, Fuzhou, Fujian Province, China
| |
Collapse
|
91
|
Martínez-Sancho E, Dorado-Liñán I, Hacke UG, Seidel H, Menzel A. Contrasting Hydraulic Architectures of Scots Pine and Sessile Oak at Their Southernmost Distribution Limits. FRONTIERS IN PLANT SCIENCE 2017; 8:598. [PMID: 28473841 PMCID: PMC5397420 DOI: 10.3389/fpls.2017.00598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/03/2017] [Indexed: 05/05/2023]
Abstract
Many temperate European tree species have their southernmost distribution limits in the Mediterranean Basin. The projected climatic conditions, particularly an increase in dryness, might induce an altitudinal and latitudinal retreat at their southernmost distribution limit. Therefore, characterizing the morphological and physiological variability of temperate tree species under dry conditions is essential to understand species' responses to expected climate change. In this study, we compared branch-level hydraulic traits of four Scots pine and four sessile oak natural stands located at the western and central Mediterranean Basin to assess their adjustment to water limiting conditions. Hydraulic traits such as xylem- and leaf-specific maximum hydraulic conductivity (KS-MAX and KL-MAX), leaf-to-xylem area ratio (AL:AX) and functional xylem fraction (FX) were measured in July 2015 during a long and exceptionally dry summer. Additionally, xylem-specific native hydraulic conductivity (KS-N) and native percentage of loss of hydraulic conductivity (PLC) were measured for Scots pine. Interspecific differences in these hydraulic traits as well as intraspecific variability between sites were assessed. The influence of annual, summer and growing season site climatic aridity (P/PET) on intraspecific variability was investigated. Sessile oak displayed higher values of KS-MAX, KL-MAX, AL:AX but a smaller percentage of FX than Scots pines. Scots pine did not vary in any of the measured hydraulic traits across the sites, and PLC values were low for all sites, even during one of the warmest summers in the region. In contrast, sessile oak showed significant differences in KS-MAX, KL-MAX, and FX across sites, which were significantly related to site aridity. The striking similarity in the hydraulic traits across Scots pine sites suggests that no adjustment in hydraulic architecture was needed, likely as a consequence of a drought-avoidance strategy. In contrast, sessile oak displayed adjustments in the hydraulic architecture along an aridity gradient, pointing to a drought-tolerance strategy.
Collapse
Affiliation(s)
- Elisabet Martínez-Sancho
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität MünchenFreising, Germany
| | - Isabel Dorado-Liñán
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität MünchenFreising, Germany
- Departamento de Silvicultura y Gestión de los Sistemas Forestales, Centro de Investigación Forestal–Instituto Nacional de Investigación y Tecnología Agraria y AlimentariaMadrid, Spain
| | - Uwe G. Hacke
- Department of Renewable Resources, University of Alberta, EdmontonAB, Canada
| | - Hannes Seidel
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität MünchenFreising, Germany
| | - Annette Menzel
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität MünchenFreising, Germany
- Institute for Advanced Study, Technische Universität MünchenGarching, Germany
| |
Collapse
|
92
|
Niu C, Meinzer FC, Hao G. Divergence in strategies for coping with winter embolism among co‐occurring temperate tree species: the role of positive xylem pressure, wood type and tree stature. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12868] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cun‐Yang Niu
- Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
| | - Frederick C. Meinzer
- USDA Forest Service Forestry Sciences Laboratory 3200 SW Jefferson Way Corvallis OR97331 USA
| | - Guang‐You Hao
- Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
| |
Collapse
|
93
|
McCulloh KA, Petitmermet J, Stefanski A, Rice KE, Rich RL, Montgomery RA, Reich PB. Is it getting hot in here? Adjustment of hydraulic parameters in six boreal and temperate tree species after 5 years of warming. GLOBAL CHANGE BIOLOGY 2016; 22:4124-4133. [PMID: 27122300 DOI: 10.1111/gcb.13323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 02/27/2016] [Indexed: 05/26/2023]
Abstract
Global temperatures (T) are rising, and for many plant species, their physiological response to this change has not been well characterized. In particular, how hydraulic parameters may change has only been examined experimentally for a few species. To address this, we measured characteristics of the hydraulic architecture of six species growing in ambient T and ambient +3.4 °C T plots in two experimentally warmed forest sites in Minnesota. These sites are at the temperate-boreal ecotone, and we measured three species from each forest type. We hypothesized that relative to boreal species, temperate species near their northern range border would increase xylem conduit diameters when grown under elevated T. We also predicted a continuum of responses among wood types, with conduit diameter increases correlating with increases in the complexity of wood structure. Finally, we predicted that increases in conduit diameter and specific hydraulic conductivity would positively affect photosynthetic rates and growth. Our results generally supported our hypotheses, and conduit diameter increased under elevated T across all species, although this pattern was driven predominantly by three species. Two of these species were temperate angiosperms, but one was a boreal conifer, contrary to predictions. We observed positive relationships between the change in specific hydraulic conductivity and both photosynthetic rate (P = 0.080) and growth (P = 0.012). Our results indicate that species differ in their ability to adjust hydraulically to increases in T. Specifically, species with more complex xylem anatomy, particularly those individuals growing near the cooler edge of their range, appeared to be better able to increase conduit diameters and specific hydraulic conductivity, which permitted increases in photosynthesis and growth. Our data support results that indicate individual's ability to physiologically adjust is related to their location within their species range, and highlight that some wood types may adjust more easily than others.
Collapse
Affiliation(s)
| | - Joshua Petitmermet
- Department of Forest Engineering, Resources, and Management, Oregon State University, Corvallis, OR, 97331, USA
| | - Artur Stefanski
- Department of Forest Resources, University of Minnesota, St Paul, MN, 55108, USA
| | - Karen E Rice
- Department of Forest Resources, University of Minnesota, St Paul, MN, 55108, USA
| | - Roy L Rich
- Department of Forest Resources, University of Minnesota, St Paul, MN, 55108, USA
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Rebecca A Montgomery
- Department of Forest Resources, University of Minnesota, St Paul, MN, 55108, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St Paul, MN, 55108, USA
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, 2753, Australia
| |
Collapse
|
94
|
Lens F, Vos RA, Charrier G, van der Niet T, Merckx V, Baas P, Aguirre Gutierrez J, Jacobs B, Chacon Dória L, Smets E, Delzon S, Janssens SB. Scalariform-to-simple transition in vessel perforation plates triggered by differences in climate during the evolution of Adoxaceae. ANNALS OF BOTANY 2016; 118:1043-1056. [PMID: 27498812 PMCID: PMC5055826 DOI: 10.1093/aob/mcw151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 05/05/2023]
Abstract
Background and Aims Angiosperms with simple vessel perforations have evolved many times independently of species having scalariform perforations, but detailed studies to understand why these transitions in wood evolution have happened are lacking. We focus on the striking difference in wood anatomy between two closely related genera of Adoxaceae, Viburnum and Sambucus, and link the anatomical divergence with climatic and physiological insights. Methods After performing wood anatomical observations, we used a molecular phylogenetic framework to estimate divergence times for 127 Adoxaceae species. The conditions under which the genera diversified were estimated using ancestral area reconstruction and optimization of ancestral climates, and xylem-specific conductivity measurements were performed. Key Results Viburnum, characterized by scalariform vessel perforations (ancestral), diversified earlier than Sambucus, having simple perforations (derived). Ancestral climate reconstruction analyses point to cold temperate preference for Viburnum and warm temperate for Sambucus. This is reflected in the xylem-specific conductivity rates of the co-occurring species investigated, showing that Viburnum lantana has rates much lower than Sambucus nigra. Conclusions The lack of selective pressure for high conductive efficiency during early diversification of Viburnum and the potentially adaptive value of scalariform perforations in frost-prone cold temperate climates have led to retention of the ancestral vessel perforation type, while higher temperatures during early diversification of Sambucus have triggered the evolution of simple vessel perforations, allowing more efficient long-distance water transport.
Collapse
Affiliation(s)
- Frederic Lens
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
| | - Rutger A. Vos
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
| | | | - Timo van der Niet
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
- School of Life Sciences, University of Kwazulu-Natal, P. Bag X01, 3209, Scottsville, South Africa
| | - Vincent Merckx
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
| | - Pieter Baas
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
| | - Jesus Aguirre Gutierrez
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
- Institute for Biodiversity and Ecosystem Dynamics, Computation Geo-Ecology, University of Amsterdam, Amsterdam, The Netherlands
| | - Bart Jacobs
- Section Ecology, Evolution and Biodiversity Conservation, KU Leuven, Belgium
| | - Larissa Chacon Dória
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
| | - Erik Smets
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300RA Leiden, The Netherlands
- Section Ecology, Evolution and Biodiversity Conservation, KU Leuven, Belgium
| | - Sylvain Delzon
- INRA, University of Bordeaux, UMR BIOGECO, F-33450 Talence, France
| | | |
Collapse
|
95
|
Umebayashi T, Utsumi Y, Koga S, Murata I, Fukuda K. Differences in drought- and freeze-induced embolisms in deciduous ring-porous plant species in Japan. PLANTA 2016; 244:753-760. [PMID: 27376942 DOI: 10.1007/s00425-016-2564-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/22/2016] [Indexed: 06/06/2023]
Abstract
Deciduous ring-porous species in Japan shed all of their leaves under severe water stress before large vessels in earlywood are embolized, and embolization take place during winter. Water in deciduous ring-porous species is mainly conducted upward via large earlywood vessels of the current year. Water columns in large vessels are vulnerable to drought-induced and freeze stress-induced embolisms. Although a vulnerability curve can be created to estimate the hydraulic capacity of plants, it remains unclear why the loss of conductivity in potted plants of ring-porous species does not reach 100 % under severe drought stress. In this study, two deciduous ring-porous species in Japan (Kalopanax septemlobus and Toxicodendron trichocarpum) were used to explain the species-specific pattern in the water-conducting pathway of the stem. We monitored and visualized the spatial distribution of xylem embolisms in the stem of K. septemlobus saplings under drought stress and freeze stress using compact magnetic resonance imaging and cryo-scanning microscopy. In addition, we evaluated the water ascent in the stems of both species using a dye uptake method. Although embolisms of large vessels were observed under drought stress and in winter, all leaves were dropped to avoid fatal water loss after embolization of some large vessels. In contrast, all large vessels were embolized in winter. Larger-diameter vessels of latewood in T. trichocarpum tended to function in trees growing in the warm temperate zone. Thus, our results suggest that the unclear curve may be derived from a discrepancy between leaf water potential and actual water potential in the xylem under severe drought stress. The frequency of xylem embolisms in deciduous ring-porous species in Japan mainly depends on the number of freeze-thaw cycles.
Collapse
Affiliation(s)
- Toshihiro Umebayashi
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
| | | | - Shinya Koga
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Ikue Murata
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Kenji Fukuda
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| |
Collapse
|
96
|
Wood anatomy of Juniperus communis: a promising proxy for palaeoclimate reconstructions in the Arctic. Polar Biol 2016. [DOI: 10.1007/s00300-016-2021-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
97
|
Murakami Y, Miki NH, Yang L, Zhang G, Wang LH, Yoshikawa K. Water transport properties of seven woody species from the semi-arid Mu Us Sandy Land, China. LANDSCAPE AND ECOLOGICAL ENGINEERING 2016. [DOI: 10.1007/s11355-015-0290-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
98
|
Ryu J, Hwang BG, Kim YX, Lee SJ. Direct observation of local xylem embolisms induced by soil drying in intact Zea mays leaves. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2617-26. [PMID: 26946123 PMCID: PMC4861012 DOI: 10.1093/jxb/erw087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The vulnerability of vascular plants to xylem embolism is closely related to their stable long-distance water transport, growth, and survival. Direct measurements of xylem embolism are required to understand what causes embolism and what strategies plants employ against it. In this study, synchrotron X-ray microscopy was used to non-destructively investigate both the anatomical structures of xylem vessels and embolism occurrence in the leaves of intact Zea mays (maize) plants. Xylem embolism was induced by water stress at various soil drying periods and soil water contents. X-ray images of dehydrated maize leaves showed that the ratio of gas-filled vessels to all xylem vessels increased with decreased soil water content and reached approximately 30% under severe water stress. Embolism occurred in some but not all vessels. Embolism in maize leaves was not strongly correlated with xylem diameter but was more likely to occur in the peripheral veins. The rate of embolism formation in metaxylem vessels was higher than in protoxylem vessels. This work has demonstrated that xylem embolism remains low in maize leaves under water stress and that there xylem has characteristic spatial traits of vulnerability to embolism.
Collapse
Affiliation(s)
- Jeongeun Ryu
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea
| | - Bae Geun Hwang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea
| | - Yangmin X Kim
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea
| | - Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea
| |
Collapse
|
99
|
Savage JA, Clearwater MJ, Haines DF, Klein T, Mencuccini M, Sevanto S, Turgeon R, Zhang C. Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology? PLANT, CELL & ENVIRONMENT 2016; 39:709-25. [PMID: 26147312 DOI: 10.1111/pce.12602] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/30/2015] [Accepted: 06/19/2015] [Indexed: 05/02/2023]
Abstract
Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment.
Collapse
Affiliation(s)
- Jessica A Savage
- Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA, 02131, USA
| | | | - Dustin F Haines
- Department of Environmental Conservation, University of Massachusetts, 160 Holdsworth Way, Amherst, MA, 01003, USA
| | - Tamir Klein
- Institute of Botany, University of Basel, Schoenbeinstrasse 6, 4056, Basel, Switzerland
| | - Maurizio Mencuccini
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, EH9 3JN, Edinburgh, UK
- ICREA at CREAF, Campus de UAB, Cerdanyola del Valles, Barcelona, 08023, Spain
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Robert Turgeon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Cankui Zhang
- Department of Agronomy, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
100
|
O’Keefe K, Nippert JB, Swemmer AM. Savanna Tree Seedlings are Physiologically Tolerant to Nighttime Freeze Events. FRONTIERS IN PLANT SCIENCE 2016; 7:46. [PMID: 26870065 PMCID: PMC4735699 DOI: 10.3389/fpls.2016.00046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/12/2016] [Indexed: 05/26/2023]
Abstract
Freeze events can be important disturbances in savanna ecosystems, yet the interactive effect of freezing with other environmental drivers on plant functioning is unknown. Here, we investigated physiological responses of South African tree seedlings to interactions of water availability and freezing temperatures. We grew widely distributed South African tree species (Colophospermum mopane, Combretum apiculatum, Acacia nigrescens, and Cassia abbreviata) under well-watered and water-limited conditions and exposed individuals to nighttime freeze events. Of the four species studied here, C. mopane was the most tolerant of lower water availability. However, all species were similarly tolerant to nighttime freezing and recovered within one week following the last freezing event. We also show that water limitation somewhat increased freezing tolerance in one of the species (C. mopane). Therefore, water limitation, but not freezing temperatures, may restrict the distribution of these species, although the interactions of these stressors may have species-specific impacts on plant physiology. Ultimately, we show that unique physiologies can exist among dominant species within communities and that combined stresses may play a currently unidentified role in driving the function of certain species within southern Africa.
Collapse
|