Response and mechanism of plant leaf nitrogen and phosphorus resorption efficiency to nutrient addition in an alpine meadow

Objective The purpose of our study was to reveal the response and mechanism of plant leaf nutrient resorption efficiency to nitrogen and phosphorus addition and their interaction, and to clarify the diversity of plant nutrient use strategies in alpine meadows.

Method To answer this question, we performed an experiment of N and P addition in an alpine meadow, measured leaf nutrient resorption efficiency in four dominant species (Elymus nutans, Deschampsia cespitosa, Artemisia roxburghiana, Potentilla anserina).

Result (1) N addition had positive effects on leaf N resorption efficiency (NRE) in graminoids, but the leaf NRE of forbs was not affected by N addition, while it did not affect P resorption efficiency (PRE) among four plant species. (2) P addition had no significant effect on the leaf NRE of all plants and the leaf PRE of two forbs, but increased the leaf PRE of graminoids. (3) N and P addition together reduced leaf NRE in E. nutans, A. roxburghiana and P. anserina, but increased NRE in D. cespitosa. Moreover, the combination of N and P addition had not significant effect on leaf PRE of four plants.

Conclusion Overall, our study indicates that alpine plants adopt three nutrient resorption strategies for more nutrient supply: full resorption (increase green leaf nutrient but no change in senescent leaf), partial resorption (more increase in green leaf nutrient than senescent leaf) and no resorption (similar increase in green and senescent leaf nutrient). These findings provide implications for understanding the diversity and complementarity of nutrient internal circulation strategies in alpine plants.