Abstract: Nutrient resorption is an important nutrient conservation mechanism of plants and an important component of nutrient cycling. Temperature change can affect nutrient resorption of plants. To explore the responses of nutrient resorption of Carex muliensis in an alpine marsh on Zoigê Plateau to climate warming, we measured nitrogen (N) and phosphorus (P) contents of mature and senescent leaves of C. muliensis in a field simulated warming experiment, and analyzed the difference of resorption efficiency. The results showed that the average contents of leaf N and P of C. muliensis were 11.44 and 1.19 mg·g^-1 respectively, and the average N resorption efficiency (NRE) and P resorption efficiency (PRE) were 61.8% and 69.0% respectively. Warming significantly decreased N content in mature leaves and increased P content in senescent leaves (P<0.01), but did not affect P content in mature leaves and N content in senescent leaves. Warming led to a significant decrease in N:P in mature and senescent leaves (P<0.01), NRE (P<0.05), and PRE (P<0.01). NRE and PRE of C. muliensis were significantly positively correlated with the N and P contents of mature leaves, and negatively correlated with the N and P contents of senescent leaves. Moreover, the growth of C. muliensis was limited by P, and the increase in temperature might lead to the change of nutrient limitation, indicating that the nutrient resorption of C. muliensis may also be regulated by stoichiometry. These results are helpful to understand and predict the responses of nutrient cycling in the Zoigê Plateau to future climate changes, and provide data support and experimental evidence for the prediction of NRE change of alpine marshes under climate warming.

Key words: resorption efficiency, nitrogen and phosphorus content, Carex muliensis, warming