Physiological Characteristics and Environmental Adaptability of Salix psammophila from Different Provenances

To conduct ecological restoration in the Kubuqi sandy land and to select suitable superior Salix psammophila provenances, four provenances were selected from Dalate Banner, Ordos (DLT), Wushen Banner, Ordos (WSQ), Yulin, Shaanxi (YL), and Yanchi, Ningxia (YC). All cuttings were interplanted and established at an experimental site, and stumping was conducted five years after establishment. Six months after stumping, 11 parameters, including growth characteristics, gas exchange parameters, and photosynthetic pigments, were systematically measured. There were significant differences in plant height and branch number among Salix psammophila from different provenances, while there was no significance in the number of branches among different provenances. The daily variation in net photosynthetic rate (Pn) was significantly different among various Salix psammophila from different provenances, with highest in that from WSQ. The daily variations in stomatal conductance (Gs) and transpiration rate (Tr) from various provenances are relatively consistent, showing a unimodal trend. In terms of pigment content, the WSQ provenance exhibited the highest chlorophyll a content, while the YC provenance showed the highest carotenoid content. The variation coefficients of each parameters ranged 2.607–40.619%, with the highest for branch number, while the lowest for intercellular CO2 concentration. Cluster analysis divided the Salix psammophila from four provenances into two groups, with DLT and YL being one group, and WSQ and YC being the other one. The results of entropy weight TOPSIS showed that the comprehensive ranking of various provenances was: WSQ > YC > YL > DLT, indicating the physiological properties of WSQ being superior to others, indicating its relatively high ecological adaptability in the semi-arid environment of the Kubuqi sandy land, and it can be used as a preferred provenance for ecological restoration and promotion applications.