Leaf nutrient stoichiometry of plants in the phosphorus-enriched soils of the Lake Dianchi watershed,southwestern China
滇池流域富磷区不同土壤磷水平下植物叶片的养分化学计量特征

Aims Understanding the stoichiometry of nutrient elements of plants growing in phosphorus-enriched areas can help characterize plant differentiation and guide ecological restoration in different biogeochemical environments. The Lake Dianchi watershed of southwestern China has P-enriched soils, and its main plant species may illustrate the relationship between plant ecological traits and the environment. Our aim was to test whether different plant life forms living at different P levels in this area have different patterns of leaf nutrient stoichiometry. Methods We collected leaf samples from 75 adult plants and soil samples from their root-zones in P-enriched areas and reference sites within the watershed. We determined N, P and K contents of leaves and total P contents of soil samples and calculated element ratios. Important findings The arithmetic means of leaf C, N and K were 441.42, 16.17 and 13.57 mg·g–1, respectively, and the geometric mean of leaf P was 1.92 mg·g–1. Significant correlations among leaf C, N, P and K were observed in all plant species. Higher P and K contents were observed in plants growing in higher P areas, but higher N/P and K/P were observed in lower P sites. Leaf nutrient concentration was significantly higher in herbaceous plants than in woody plants, but there was no difference in leaf nutrient concentrations between trees and shrubs. Leaf N/P and K/P were correlated negatively with soil P content. Results suggested that plant growth and vegetation development in the Lake Dianchi watershed were limited by low soil N contents and plant growth enhanced by N addition should be important for vegetation resilience and prevention of non-point source pollution in the process of ecosystem restoration.