关键词: 氮添加, 毛竹, 化学计量学, 渗透物质, 抗氧化酶

Abstract: Atmospheric nitrogen deposition is one of the important issues of global changes, which may cause stoichiometric imbalances in plants and negatively affect plant metabolism. Phyllostachys edulis is a bamboo species with long cultivation history, wide distribution, and important economic value in China. In this study, we conducted a field experiment with three nitrogen addition levels \[control (CT), low nitrogen (LN), and high nitrogen additions (HN)\] to simulate nitrogen deposition in a Ph. edulis forest in Daiyunshan National Nature Reserve, Fujian Province, China. The effects of nitrogen addition on the stoichiometry and metabolic components of Ph. edulis were investigated by determining basic physical and chemical properties of soils, carbon, nitrogen, and phosphorus contents of Ph. edulis leaves and roots, the biomass of fine roots, and the metabolic component contents of leaves. The results showed that nitrogen addition significantly increased phosphorus content, carbon∶phosphorus (C∶P) ratio and nitrogen∶phosphorus (N∶P) ratio of leaves, but did not affect those variables and biomass in fine roots. Those results indicated that phosphorus use efficiency of Ph. edulis differed across organs in response to nitrogen addition. High nitrogen addition significantly increased leaf malondialdehyde content and decreased superoxide dismutase activity, whereas low nitrogen addition had no significant effect on the metabolic components in leaves. This result suggested that Ph. edulis can maintain relatively stable metabolic activity under low nitrogen addition. In summary, this study clarified nutrient use characteristics of different organs of Ph. edulis under nitrogen deposition, and identified the stronger adaptive strategy of leaves under low nitrogen addition.

Key words: nitrogen addition , Phyllostachys edulis, stoichiometry, osmotic substance, antioxidant enzyme