The daily dynamics of photosynthesis and its influencing factors in the Otindag sandy land Salix gordejevii

Abstract This study focuses on the Salix gordejevii, inhabiting various habitats (mobile dune, semi-fixed dune, fixed dune, dune slack) in the Otingdag Sandy Land. Through the analysis of daily dynamics of environmental factors within different habitats and an in-depth investigation into the daily variations of photosynthetic characteristics of Salix gordejevii and their influencing factors, this study aims to elucidate the photosynthetic physiological and ecological adaptation strategies of Salix gordejevii. Results show that: (a) Significant daily dynamic variations of environmental factors exist among different habitats of Salix gordejevii, displaying environmental heterogeneity; (b) Salix gordejevii exhibits significant daily variations in photosynthetic characteristics among different habitats; (c) The influence of environmental factors on plant photosynthesis (Pn) is the result of comprehensive effects. The main environmental factors affecting the Pn of Salix gordejevii leaves include photosynthetically active radiation (PAR), stomatal conductance (Gs), intercellular CO2 concentration (Ci), leaf temperature (tl), transpiration rate (Tr), atmospheric temperature (ta), vapor pressure deficit (Vpd), and stomatal limitation (Ls).The research results contribute to further understanding the decline mechanism of Salix gordejevii and lay a theoretical foundation for revealing the photosynthetic physiological and ecological adaptability of Salix gordejevii.