The shape characteristics of four low plants in non-growing season in Taklimakan Desert

Winter and spring constitute a weak period for the biological protection system, where low shrubs and grass vegetation play an important role. Identifying the shape and branching characteristics of these plants can provide a scientific basis for assessing and utilizing their sand-fixation capacity. In this paper, Apocynum venetum, Launaea polydichotoma, Karelinia caspia, and Alhagi sparsifolia in the hinterland of the Taklimakan Desert were used as research subjects. Their plant shape characteristics were observed on-site, and their sand control ability was statistically analyzed. The results showed the following: 1) Distinct non-growing season morphologies among the species—cylindrical for A. venetum, spherical for L. polydichotoma, ellipsoidal for A. sparsifolia, and inverted cone for K. caspia. The relative sizes of each plant shape index also differed, plant height was ranked as follows: A. venetum > A. sparsifolia > K. caspia > L. polydichotoma; crown width: K. caspia > K. caspia > A. venetum > A. sparsifolia; profile area: A. venetum > L. polydichotoma > A. sparsifolia > K. caspia; plant shape volume: A. venetum > L. polydichotoma > K. caspia > A. sparsifolia. 2) Their branching characteristics differed: The number of primary branches was the highest in K. caspia, the number of secondary branches was the highest in A. sparsifolia and L. polydichotoma, and A. venetum has more secondary branches and less primary branches, the proportion of lateral image area and the proportion of branch volume were in the order: K. caspia > A. sparsifolia > L. polydichotoma > A. venetum, and the porosity was in the order: A. venetum > L. polydichotoma > A. sparsifolia > K. caspia, it also show their relative sand control capacity. 3) The plant shape characteristics of these four species are closely related to their sand control capacity. The plant shapes of K. caspia, A. sparsifolia, and L. polydichotoma are classified as wide and short types with strong sand control ability, while the plant shape of A. venetum is classified as a narrow and tall type with weak sand control ability. These results provide important information for explaining the relative stability maintenance mechanisms of desert steppe and serve as a significant reference for the scientific evaluation of the ecological functions of low shrubs and herbaceous plants in aeolian sand environments, as well as for the selection of plant species for desertification control.