Abstract: This study used a method based on a spatial series in place of a temporal series and on the selection of T. ramosissima shrubs at the different developmental stages of coppice dunes as research subjects. It investigates the chlorophyll fluorescence characteristics and non-structural carbohydrates (NSC) of T. ramosissima on coppice dunes. The results indicated that, (1) T. ramosissima showed a significant increase in photosynthetic pigment content concomitant with a decrease in actual photochemical efficiency (Y_(II)) as coppice dune development progressed. Simultaneously, the reduction of the plastoquinone (PQ) pool intensified, the apparent electron transport rate (ETR) increased, and the quantum yield of regulated energy dissipation significantly increased. This adaptations enabled T. ramosissima to dissipate excess light energy by enhancing its non-photochemical energy dissipation mechanisms. (2) Photosynthetically active radiation (PAR) and T. ramosissima leaf temperature (T_L) gradually increased during coppice dune development, whereas soil water content gradually decrease, leading to increased stress on T. ramosissima and a subsequent decrease in NSC content. This increased stress put T. ramosissima at risk of “carbon starvation,” resulting in a gradual decline in photosynthesis, biomass accumulation, and ultimately, death. (3) The correlations between various indicators of T. ramosissima were significant, with the highest degree of association and marked enhancement of synergistic effects in the growth and decline stages of coppice dunes. Comprehensive analysis revealed that high soil moisture content can help alleviate water stress, improve light energy use efficiency, and enhance the photosynthetic carbon assimilation process in T. ramosissima during coppice dune development.

Key words: Photochemical activity, Nonstructural carbohydrates, Tamarix ramosissima, Coppice dunes, Gurbantonggut Desert