Woody species with higher hydraulic efficiency or lower photosynthetic capacity discriminate more against 13C at the global scale
Yanting Hu, K. V. Schäfer, Songjiang Hu, Wenneng Zhou, Dong Xiang, Yelin Zeng, Shuai Ouyang, Liang Chen, Pifeng Lei, Xiangwen Deng, Zhonghui Zhao, Xi Fang, Wenhua Xiang
Abstract
Leaf carbon isotope composition ( δ 13 C) 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 δ 13 C. Association between photosynthetic ability and leaf δ 13 C has been examined, however, how hydraulic traits influence leaf δ 13 C has not been fully understood. To fill this gap, we investigated the variations in leaf δ 13 C among 2591 woody species (547 shrub and 2044 tree species), and analyzed the link of leaf δ 13 C with leaf photosynthetic and xylem hydraulic traits. Our result showed that leaf δ 13 C was positively correlated to leaf photosynthetic ability and capacity. For hydraulic traits, leaf δ 13 C was negatively related to hydraulic conductivity ( K s ), xylem pressure inducing 50 % loss of hydraulic conductivity ( P 50 ) and vessel diameter ( V dia ). Associations of leaf δ 13 C with xylem hydraulic traits indicate woody species with stronger hydraulic safety discriminated less against 13 C, while woody species with higher hydraulic efficiency had more negative leaf δ 13 C. Shrub species, which showed a lower V dia and P 50 , had a significant less negative leaf δ 13 C than tree species. Furthermore, woody species inhabiting in dry regions discriminated less against 13 C than those growing in humid regions. Moreover, leaf δ 13 C 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 13 C and adopt the provident water use strategy.