关键词: 养分重吸收, 退化, 水土保持, 养分保存

Abstract: Nutrient resorption is an important nutrient conservation strategy for plants to reduce their dependence on environmental nutrients. We examined the responses of nutrient resorption of four common plant species used for soil and water conservation to soil nutrient changes, namely, Populus × xiaohei, Larix gmelinii, Bromus inermis and Amorpha fruticosa. Soil degradation levels of natural conditions were simulated by soil stripping. The results showed that there were significant differences in N and P contents of fresh and senesced leaves under different soil degradation levels. The differences in the N and P resorption efficiency were not significant but the differences in the resorption proficiency (i.e., the N and P contents of senesced leaves) were significant across different soil degradation levels. N and P resorption were significantly correlated with foliar N and P contents. The nutrient contents in leaves and soil nutrient factors were important factors affecting the nutrient resorption, explaining 61%-96% of the variation in N and P resorption efficiency and resorption proficiency. Nutrient resorption proficiency was more sensitive to soil nutrients than resorption efficiency. Leaf nutrient content was the main factor regulating nutrient resorption. There were differences in the resorption capacity of different species. Bromus inermis had the highest resorption proficiency, with a strong nutrient conservation capacity to minimize its dependence on soil nutrients. By contrast, Populus × xiaohei had lower resorption proficiency but higher quality of senesced leaves, which allowed more nutrients to be returned through the senesced leaves.

Key words: nutrient resorption, degradation, soil and water conservation, nutrient conservation