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Baca Cabrera JC, Hirl RT, Zhu J, Schäufele R, Ogée J, Schnyder H. 18 O enrichment of sucrose and photosynthetic and nonphotosynthetic leaf water in a C 3 grass-atmospheric drivers and physiological relations. PLANT, CELL & ENVIRONMENT 2023. [PMID: 37376738 DOI: 10.1111/pce.14655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 05/19/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023]
Abstract
The 18 O enrichment (Δ18 O) of leaf water affects the Δ18 O of photosynthetic products such as sucrose, generating an isotopic archive of plant function and past climate. However, uncertainty remains as to whether leaf water compartmentation between photosynthetic and nonphotosynthetic tissue affects the relationship between Δ18 O of bulk leaf water (Δ18 OLW ) and leaf sucrose (Δ18 OSucrose ). We grew Lolium perenne (a C3 grass) in mesocosm-scale, replicated experiments with daytime relative humidity (50% or 75%) and CO2 level (200, 400 or 800 μmol mol-1 ) as factors, and determined Δ18 OLW , Δ18 OSucrose and morphophysiological leaf parameters, including transpiration (Eleaf ), stomatal conductance (gs ) and mesophyll conductance to CO2 (gm ). The Δ18 O of photosynthetic medium water (Δ18 OSSW ) was estimated from Δ18 OSucrose and the equilibrium fractionation between water and carbonyl groups (εbio ). Δ18 OSSW was well predicted by theoretical estimates of leaf water at the evaporative site (Δ18 Oe ) with adjustments that correlated with gas exchange parameters (gs or total conductance to CO2 ). Isotopic mass balance and published work indicated that nonphotosynthetic tissue water was a large fraction (~0.53) of bulk leaf water. Δ18 OLW was a poor proxy for Δ18 OSucrose , mainly due to opposite Δ18 O responses of nonphotosynthetic tissue water (Δ18 Onon-SSW ) relative to Δ18 OSSW , driven by atmospheric conditions.
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Affiliation(s)
- Juan C Baca Cabrera
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
- Forschungszentrum Jülich GmbH, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Jülich, Germany
| | - Regina T Hirl
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | - Jianjun Zhu
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | - Rudi Schäufele
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
| | | | - Hans Schnyder
- Technische Universität München, TUM School of Life Sciences, Lehrstuhl für Grünlandlehre, Freising-Weihenstephan, Germany
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Kullberg AT, Feeley KJ. Limited acclimation of leaf traits and leaf temperatures in a subtropical urban heat island. TREE PHYSIOLOGY 2022; 42:2266-2281. [PMID: 35708568 DOI: 10.1093/treephys/tpac066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
The consequences of rising temperatures for trees will vary between species based on their abilities to acclimate their leaf thermoregulatory traits and photosynthetic thermal tolerances. We tested the hypotheses that adult trees in warmer growing conditions (i) acclimate their thermoregulatory traits to regulate leaf temperatures, (ii) acclimate their thermal tolerances such that tolerances are positively correlated with leaf temperature and (iii) that species with broader thermal niche breadths have greater acclimatory abilities. To test these hypotheses, we measured leaf traits and thermal tolerances of seven focal tree species across steep thermal gradients in Miami's urban heat island. We found that some functional traits varied significantly across air temperatures within species. For example, leaf thickness increased with maximum air temperature in three species, and leaf mass per area and leaf reflectance both increased with air temperature in one species. Only one species was marginally more homeothermic than expected by chance due to acclimation of its thermoregulatory traits, but this acclimation was insufficient to offset elevated air temperatures. Thermal tolerances acclimated to higher maximum air temperatures in two species. As a result of limited acclimation, leaf thermal safety margins (TSMs) were narrower for trees in hotter areas. We found some support for our hypothesis that species with broader thermal niches are better at acclimating to maintain more stable TSMs across the temperature gradients. These findings suggest that trees have limited abilities to acclimate to high temperatures and that thermal niche specialists may be at a heightened risk of thermal stress as global temperatures continue to rise.
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Affiliation(s)
- Alyssa T Kullberg
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
| | - Kenneth J Feeley
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
- Fairchild Tropical Botanic Garden, Coral Gables, FL 33156, USA
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Liang J, Wright JS, Cui X, Sternberg L, Gan W, Lin G. Leaf anatomical traits determine the 18 O enrichment of leaf water in coastal halophytes. PLANT, CELL & ENVIRONMENT 2018; 41:2744-2757. [PMID: 29996176 DOI: 10.1111/pce.13398] [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: 01/15/2018] [Accepted: 07/02/2018] [Indexed: 06/08/2023]
Abstract
Anatomical adaptations to high-salinity environments in mangrove leaves may be recorded in leaf water isotopes. Recent studies observed lower 18 O enrichment (ΔL ) of leaf water with respect to source water in three mangrove species relative to adjacent freshwater trees, but the factors that govern this phenomenon remain unclear. To resolve this issue, we investigated leaf traits and ΔL in 15 species of true mangrove plants, 14 species of adjacent freshwater trees, and 4 species of semi-mangrove plants at five study sites along south-eastern coast of China. Our results confirm that ΔL was generally 3-4‰ lower for mangrove species than for adjacent freshwater or semi-mangrove species. We hypothesized that higher leaf water content (LWC) and lower leaf stomatal density (LS) both played important roles in reducing ΔL in mangroves relative to nearby freshwater plants. Both differences acted to elongate effective leaf mixing length (L) in mangroves by about 200% and lower stomatal conductance by about 30%. Péclet models based on both LWC and LS could accurately predict ΔL . Our findings highlight the potential species-specific anatomical determinants of ΔL (or L), which has important implications for the interpretation of environmental information from metabolites produced by leaf water isotopes in palaeoclimate research.
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Affiliation(s)
- Jie Liang
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Joint Center for Global Change Studies, Beijing, China
- Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Jonathan S Wright
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Joint Center for Global Change Studies, Beijing, China
| | - Xiaowei Cui
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Joint Center for Global Change Studies, Beijing, China
- Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Leonel Sternberg
- Department of Biology, University of Miami, Coral Gables, Florida
| | - Weixiu Gan
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Joint Center for Global Change Studies, Beijing, China
- Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Guanghui Lin
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Joint Center for Global Change Studies, Beijing, China
- Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
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Larcher L, Hara-Nishimura I, Sternberg L. Effects of stomatal density and leaf water content on the ¹⁸O enrichment of leaf water. THE NEW PHYTOLOGIST 2015; 206:141-151. [PMID: 25408145 DOI: 10.1111/nph.13154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
Leaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density. We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment. High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment. We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant-based metabolic proxies in paleoclimate studies.
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Affiliation(s)
- Leticia Larcher
- Programa de Pós Graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Ikuko Hara-Nishimura
- Graduate School of Science, Department of Botany, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Leonel Sternberg
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL, 33124, USA
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