祁连山东缘高寒草甸植物及各部位对氮素添加的响应

Responses of Alpine Meadow Plants and Their Parts to Nitrogen Addition in the Eastern Qilian Mountains

为探究氮添加处理下高寒草甸草原植物的氮吸收和分配模式,本研究以祁连山东段高寒草甸草原为研究对象,分别施入0,10,20,30,40 g·m^(-2)的尿素,测定不同施氮水平下不同经济类群和优势种植物的生物量、整个植株及各部位氮含量等。结果表明:相比于豆科和杂类草,禾本科和莎草科植物对于氮素的利用率更为高效;施氮与扁蓿豆(Trigonella ruthenica L.)、矮生嵩草(Kobresia humilis)、垂穗披碱草(Elymus nutans)植物氮含量显著相关,与赖草(Leymus secalinus)和球花蒿(Artemisia smithii)的相关性较弱;施氮后植物叶片氮含量最高,其次是穗/花,茎的氮含量最低,且施氮对于植物叶片的氮含量有显著影响,对茎和穗/花的影响不显著。

In order to explore the nitrogen absorption and allocation patterns of alpine meadow plants under different nitrogen addition treatments,the urea was applied to alpine meadow in the eastern Qilian Mountains(0,10,20,30,40 g·m^(-2))to measuring the biomass of various economic groups and dominant species,as well as nitrogen contents of the whole plants and their organs under these five different nitrogen levels.The results showed that the nitrogen utilization ratio of gramineae and sedges were higher than that of legumes and forbs.The nitrogen contents of Trigonella ruthenica,Kobresia humilis and Elymus nutans was significantly correlated with the five nitrogen levels,but the correlation was weak for that of Leymus secalinus and Artemisia smithii.Along the different nitrogen treatments,the nitrogen content was decreased from plant leaf,panicle/flower and stem in sequence.Nitrogen addition had a significant effect on nitrogen content in leaf,but had no significant effect on stem and panicle/flower.