Nutrient and stoichiometric characteristics of various organs in three typical desert plants from extreme desert ecosystems

Abstract

Predicting how fragile and sensitive desert ecosystems will react to environmental changes depends on understanding how soil factors influence plant nutrient concentration and stoichiometry. We studied nutrients and stoichiometric characteristics of various organs of three desert plants (Alhagi sparsifolia, Tamarix ramosissima, and Calligonum caput-medusae) in Turpan (TLF), Tarim (CL), and Dzungaria (MSW) basins of Xinjiang, China. The results showed that in three regions (CL, MSW, and TLF), the nutrient levels of total nitrogen (TN) and total potassium (TK) in the leaves, roots, and branches of A. sparsifolia were significantly higher than those of C. caput-medusae. The total phosphorus (TP) contents in the leaves, roots, and branches of A. sparsifolia were significantly higher than those of T. ramosissima and C. caput-medusae. However, the nitrogen-to-phosphorus ratio in the leaf of C. caput-medusae was significantly lower compared with A. sparsifolia and T. ramosissima. A. sparsifolia had higher root organic carbon content compared with its branches and leaves, while its leaves had higher nutrient levels of TN and TK compared with its roots and branches. The leaf organic carbon contents of T. ramosissima and C. caput-medusae were lower compared with roots and branches, but higher leaf nutrients (TN, TP, and TK contents) than in roots and branches. The soil nutrients of three desert plants experienced significant nitrogen and phosphorus element limitations. Soil electrical conductivity (EC) was identified as a common environmental factor influencing the nutrient changes in the leaves, branches, and roots of desert plants. The structural equation model that soil pH was positively correlated with branch and root stoichiometry, however, soil EC was negatively correlated with root stoichiometry. This research offers a scientific foundation and essential information for the conservation and rehabilitation of desert ecosystems.