Abstract: Reaumuria soongorica is a dominant species in the desert shrubbery vegetation in arid regions of northwestern China, playing an important role in the maintenance of the stability and continuity of desert ecosystem. In this paper, a total of 407 individuals in 21 natural populations ofR. soongorica were selected from its main distribution areas to measure the leaf stable carbon isotope composition (δ¹³C) and nitrogen, phosphorus, potassium, water, proline and chlorophyll contents, with the correlations between the δ¹³C value and the test physiological parameters analyzed. The results showed that leaf δ¹³C value was significantly correlated with the contents of leaf potassium, water, and proline (P<0.001), and the correlation with leaf potassium content was most profound (r=0.793), followed by that with leaf water content (r=-0.786), indicating that the variation of leaf δ¹³C value could reflect the nutritional status of the plants, and also, their water-deficient degree. The different distribution trends in leaf δ¹³C value of R. soongoricawere likely caused by stomatal conductance, rather than by nutrient-related changes in photosynthetic efficiency under extremely low available water conditions.

Key words: Yimeng mountainous area, phosphorus loss, sloping peanut land, grass planting between ridges, Lolium multiflorum.