增温和渐进干旱条件下气孔导度与光合作用相耦合
Coupling between stomatal conductance and photosynthesis of under warming and progressive drought
袁珍珍 1汪旭明 2巩晓颖2
作者信息
- 1. 湿润亚热带生态-地理过程教育部重点实验室，福建师范大学地理科学学院，福州 350117
- 2. 福建省植物生态生理重点实验室，福州 350117;福建三明森林生态系统国家野外科学观测研究站，三明 365002;湿润亚热带生态-地理过程教育部重点实验室，福建师范大学地理科学学院，福州 350117
- 折叠
摘要
气候变暖加剧干旱胁迫，威胁森林生态系统的碳汇功能。气孔导度（gs）与光合速率（A）的耦合关系是预测碳循环的关键，但在增温与干旱协同作用下，这种耦合关系是否稳定尚不确定。本研究以两种亚热带优势树种-米槠（Castanopsis carlesii）和木荷（Schima superba）的幼苗为研究对象，采用开顶式气室（OTC）模拟增温（+1℃）并结合渐进干旱处理，以此探究叶片气体交换和叶绿素荧光参数对单一及复合环境因子的响应。结果表明，增温并未显著加剧各树种光合作用的干旱敏感性。尽管干旱引起光合速率显著降低，但gs与A始终保持紧密耦合。不同树种的气孔调节策略存在显著差异：米槠表现出"挥霍型"气孔行为（统一气孔优化模型中的斜率参数m1较高），而木荷则表现为"保守型"（m1较低）。本研究表明，在增温和渐进干旱条件下，亚热带树种维持碳-水耦合，但强调了在碳循环模型中整合树种特异性气孔参数，尤其对混交林具有重要意义。
Abstract
Climate warming intensifies drought stress, threatening the carbon sink capacity of forest ecosystems. The coupling between stomatal conductance (gs) and photosynthesis (A) is crucial for predicting carbon cycling, yet its stability under combined warming and drought remains uncertain. We conducted a controlled experiment using open-top chambers to simulate warming (+1℃) combined with a progressive droughton seedlings of two dominant subtropical tree species (Castanopsis carlesii and Schima superba). The responses of leaf gas exchange and chlorophyll fluorescence to these distinct and interactive stressors were examined. Our results show that warming did not increase photosynthetic sensitivity to progressive drought across species. Despite significant drought-induced declines in photosynthesis, gs and A remained tightly coupled.Species diverged in stomatal regulation: C. carlesii had "profligate" stomatal behaviour (high slope parameters (m1) from the unified stomatal optimization model), while S. superba was conservative (low m1). This study shows that subtropical trees can maintain carbon-water coupling during moderate warming and progressive drought, but highlights the importance of integrating species-specific stomatal parameters in carbon cycle models, particularly for mixed forests.关键词
碳同化/气候变化/干旱敏感性/温度升高/叶肉导度/干旱Key words
carbon uptake/ climate change/ drought sensitivity/ elevated temperature/ mesophyll conductance/ drought引用本文复制引用
袁珍珍,汪旭明,巩晓颖.增温和渐进干旱条件下气孔导度与光合作用相耦合[EB/OL].(2026-03-02)[2026-03-03].http://www.paper.edu.cn/releasepaper/content/202603-20.学科分类
林业/环境科学理论/环境科学基础理论/环境管理/环境污染、环境污染防治
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