Foliar water uptake and its influencing factors differ between female and male Populus euphratica

Abstract

In arid ecosystems, foliar water uptake (FWU) plays an important role in improving plant physiological performance. However, the structural and physiological response mechanism of FWU between male and female woody desert plants has not been reported. Using the dioecious desert woody plant Populus euphratica, the current study explored the structural and physiological response mechanism of male and female P. euphratica leaves to water absorption via an FWU capacity experiment based on leaf epidermal cell wall components and cell structure, osmotic adjustment, and oxidative metabolism indicators. The results showed that both male and female P. euphratica plants could absorb water through leaves. The per unit area of leaf water absorption (AFWU) and the leaf absorption speed (k) of female P. euphratica were higher than those of male P. euphratica, and the TFWU was approximately twice that of male P. euphratica. The leaf thickness (LT), palisade tissue thickness (TP) and the contents of cellulose and pectin of female were significantly larger than those of male P. euphratica. The contents of sucrose, glucose, soluble sugar, proline and peroxidase in female leaves were significantly higher than those in male leaves. Multivariate factor analysis showed that the AFWU of the leaves was strongly correlated with glucose, cellulose, TP, and catalase, and the k was strongly correlated with starch, pectin, LT, and malondialdehyde. The FWU capacity of female P. euphratica was stronger than that of male P. euphratica, which was caused by the difference in cell structure and osmotic regulatory substances. These results provide a new perspective for understanding the water utilization mechanism reproduction strategy of dioecious plants.