Evaluation of tesponses and adaptability of five perennial desert plants to environmental conditions in the Central Taklamakan Desert

Herbaceous plants and small shrubs play crucial roles in biological sand control engineering, and their stress resistance is a key factor influencing their practical application. In this study, five perennial desert plant species growing in the Tazhong Desert Botanical Garden—Karelinia caspia, Alhagi camelorum, Apocynum venetum, Ammopiptanthus mongolicus, and Amorpha fruticosa—were selected as research subjects. Leaf morphological traits and chlorophyll fluorescence parameters were measured at different growth stages to investigate their adaptive strategies to arid and saline-alkali environments. A fuzzy membership function method was employed to comprehensively evaluate their stress resistance. The results showed that: (1) Besides A. venetum, the other four species reduced water loss by modifying leaf morphological structures; (2) During periods of high summer temperatures, A .mongolicus and K. caspia maintained relatively low canopy temperatures, with canopy-air temperature differences < 0 ℃). By late summer, all five species exhibited canopy temperatures that were 1.5～4 ℃ lower than the ambient air temperature. Except for K. caspia, stomatal resistance in the other four species was highly significantly correlated with ambient temperature (P < 0.01); (3) With the exception of A. mongolicus, the other four species dissipated excess light energy through increased non-photochemical quenching (q_N), thereby protecting photosystem II. Specifically, K. caspia and A. camelorum showed approximately a twofold increase in q_N, while A. venetum and A. fruticosa exhibited an increase of more than 13-fold. In the mid-to-late growth stages, only A. mongolicus maintained a stable maximum photochemical efficiency for PSII (F_v/F_m). Comprehensive evaluation revealed varying degrees of adaptability among the five species to the central Taklamakan Desert environment, with A. mongolicus exhibiting the highest stress resistance, followed by K. caspia and A. camelorum. Thus, we recommend these as priority species for ecological restoration projects.