Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China; Huitong National Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystems in Hunan Province, Huitong, Hunan 438107, China.
Department of Earth and Environmental Sciences, Rutgers University, 195 University Avenue, Newark 07102, NJ, USA.
Sci Total Environ. 2024 Jan 15;908:168172. doi: 10.1016/j.scitotenv.2023.168172. Epub 2023 Nov 6.
Leaf carbon isotope composition (δC) provides an integrative record on the carbon and water balance of plants over long periods. Photosynthetic ability and hydraulic traits which are highly associated with stomatal behavior could affect leaf δC. Association between photosynthetic ability and leaf δC has been examined, however, how hydraulic traits influence leaf δC has not been fully understood. To fill this gap, we investigated the variations in leaf δC among 2591 woody species (547 shrub and 2044 tree species), and analyzed the link of leaf δC with leaf photosynthetic and xylem hydraulic traits. Our result showed that leaf δC was positively correlated to leaf photosynthetic ability and capacity. For hydraulic traits, leaf δC was negatively related to hydraulic conductivity (K), xylem pressure inducing 50 % loss of hydraulic conductivity (P) and vessel diameter (V). Associations of leaf δC with xylem hydraulic traits indicate woody species with stronger hydraulic safety discriminated less against C, while woody species with higher hydraulic efficiency had more negative leaf δC. Shrub species, which showed a lower V and P, had a significant less negative leaf δC than tree species. Furthermore, woody species inhabiting in dry regions discriminated less against C than those growing in humid regions. Moreover, leaf δC displayed a low phylogenetic signal based on Blomberg's K statistic. Overall, woody species with a higher leaf photosynthetic ability or stronger hydraulic safety system discriminated less against C and adopt the provident water use strategy.
叶片碳同位素组成 (δC) 为植物的碳和水分平衡提供了长期的综合记录。与气孔行为高度相关的光合作用能力和水力特性会影响叶片 δC。已经研究了光合作用能力与叶片 δC 之间的关联，但水力特性如何影响叶片 δC 尚未完全理解。为了填补这一空白，我们调查了 2591 种木本植物（547 种灌木和 2044 种乔木）之间叶片 δC 的变化，并分析了叶片 δC 与叶片光合作用和木质部水力特性之间的联系。我们的结果表明，叶片 δC 与叶片光合作用能力和容量呈正相关。对于水力特性，叶片 δC 与导水率 (K)、木质部压力诱导导水率损失 50%的压力 (P) 和导管直径 (V) 呈负相关。叶片 δC 与木质部水力特性的关联表明，具有更强水力安全的木本植物对 C 的排斥作用较小，而具有更高水力效率的木本植物具有更负的叶片 δC。导管直径 (V) 和压力 (P) 较低的灌木物种比乔木物种具有更负的叶片 δC。此外，与生长在潮湿地区的物种相比，生长在干旱地区的木本植物对 C 的排斥作用较小。此外，叶片 δC 基于 Blomberg 的 K 统计显示出较低的系统发育信号。总体而言，叶片光合作用能力较高或木质部水力安全系统较强的木本植物对 C 的排斥作用较小，采用节约用水的策略。
