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Summary Conifers prevail in the canopies of many terrestrial biomes, holding a great ecological and economic importance globally. Current increases in temperature and aridity are imposing high transpirational demands and resulting in conifer mortality. Therefore, identifying leaf structural determinants of water use efficiency is essential for predicting physiological impacts due to environmental variation.Using synchrotron‐generated microtomography imaging, we extracted leaf volumetric anatomy and stomatal traits in 34 species across conifers with a special focus onPinus, the richest conifer genus.We show that intrinsic water use efficiency (WUEi) is positively driven by leaf vein volume. Needle‐like leaves ofPinus, as opposed to flat leaves or flattened needles of other genera, showed lower mesophyll porosity, decreasing the relative mesophyll volume. This led to increased ratios of stomatal pore number per mesophyll or intercellular airspace volume, which emerged as powerful explanatory variables, predicting both stomatal conductance and WUEi.Our results clarify how the three‐dimensional organisation of tissues within the leaf has a direct impact on plant water use and carbon uptake. By identifying a suite of structural traits that influence important physiological functions, our findings can help to understand how conifers may respond to the pressures exerted by climate change.
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This content will become publicly available on March 1, 2026
High hydraulic safety, water use efficiency and a conservative resource‐use strategy in woody species of high‐altitude environments: A global study
Abstract Understanding the impact of altitude on leaf hydraulic, gas exchange, and economic traits is crucial for comprehending vegetation properties and ecosystem functioning. This knowledge also helps to elucidate species' functional strategies regarding their vulnerability or resilience to global change effects in alpine environments. Here, we conducted a global study of dataset encompassing leaf hydraulic, gas exchange, and economic traits for 3391 woody species. The results showed that high‐altitude species possessed greater hydraulic safety (KleafP50), higher water use efficiency (WUEi) and conservative resource use strategy such as higher leaf mass per area, longer leaf lifespan, lower area‐based leaf nitrogen and phosphorus contents, and lower rates of photosynthesis and dark respiration. Conversely, species at lower altitudes exhibited lower hydraulic safety (KleafP50), lower water use efficiency (WUEi) and an acquisitive resource use strategy. These global patterns of leaf traits in relation to altitude reveal the strategies that alpine plants employ for hydraulic safety, water use efficiency, and resource, which have important implications for predicting forest productivity and acclimation to rapid climate change.
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- Award ID(s):
- 1943583
- PAR ID:
- 10595476
- Publisher / Repository:
- Physiologia Plantarum
- Date Published:
- Journal Name:
- Physiologia Plantarum
- Volume:
- 177
- Issue:
- 2
- ISSN:
- 0031-9317
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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