Coordination of photosynthetic traits across soil and climate gradients

Westerband, Andrea C., Wright, Ian J., Maire, Vincent, Paillassa, Jennifer, Prentice, Iain Colin, Atkin, Owen K., Bloomfield, Keith J., Cernusak, Lucas A., Dong, Ning, Gleason, Sean M., Pereira, Caio Guilherme, Lambers, Hans, Leishman, Michelle R., Malhi, Yadvinder, and Nolan, Rachael H. (2023) Coordination of photosynthetic traits across soil and climate gradients. Global Change Biology, 29 (3). pp. 856-873.

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Abstract

"Least-cost theory" posits that C-3 plants should balance rates of photosynthetic water loss and carboxylation in relation to the relative acquisition and maintenance costs of resources required for these activities. Here we investigated the dependency of photosynthetic traits on climate and soil properties using a new Australia-wide trait dataset spanning 528 species from 67 sites. We tested the hypotheses that plants on relatively cold or dry sites, or on relatively more fertile sites, would typically operate at greater CO2 drawdown (lower ratio of leaf internal to ambient CO2, C-i:C-a) during light-saturated photosynthesis, and at higher leaf N per area (N-area) and higher carboxylation capacity (V-cmax 25) for a given rate of stomatal conductance to water vapour, g(sw). These results would be indicative of plants having relatively higher water costs than nutrient costs. In general, our hypotheses were supported. Soil total phosphorus (P) concentration and (more weakly) soil pH exerted positive effects on the N-area-g(sw) and V-cmax 25-g(sw) slopes, and negative effects on C-i:C-a. The P effect strengthened when the effect of climate was removed via partial regression. We observed similar trends with increasing soil cation exchange capacity and clay content, which affect soil nutrient availability, and found that soil properties explained similar amounts of variation in the focal traits as climate did. Although climate typically explained more trait variation than soil did, together they explained up to 52% of variation in the slope relationships and soil properties explained up to 30% of the variation in individual traits. Soils influenced photosynthetic traits as well as their coordination. In particular, the influence of soil P likely reflects the Australia's geologically ancient low-relief landscapes with highly leached soils. Least-cost theory provides a valuable framework for understanding trade-offs between resource costs and use in plants, including limiting soil nutrients.

Item ID: 76959
Item Type: Article (Research - C1)
ISSN: 1365-2486
Keywords: Australia, least-cost theory of photosynthesis, nutrient-use efficiency, optimality theory, plant functional traits, soil nutrients, soil phosphorus, trait coordination, water-use efficiency
Copyright Information: © 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited
Funders: Australian Research Council (ARC)
Projects and Grants: ARC DP170103410, ARC DP130101252, ARC CE140100008, ARC Australian Laureate Fellowship FL100100080/2011-2015
Date Deposited: 07 Dec 2022 08:23
FoR Codes: 31 BIOLOGICAL SCIENCES > 3108 Plant biology > 310806 Plant physiology @ 100%
SEO Codes: 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280102 Expanding knowledge in the biological sciences @ 100%
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