内蒙古克氏针茅草地主要植物叶片功能性状对氮素添加的响应

环境氮沉降的增加影响植物功能性状,进而改变植物群落的构成.本研究分析了中国内蒙古多伦县境内连续6年施氮肥的克氏针茅群落中5种主要植物的功能性状的变化,以探究草地植物对氮素添加的响应策略.研究发现,随着施肥量增加,草地主要植物通过增加植株高度、叶片面积、比叶面积、叶片氮、磷含量,减小叶片干物质含量,提高自身对光资源的竞争能力.该结果说明,随着环境氮输入的增加,植物的响应策略是向着叶片经济谱中低投入快回报的方向移动变化.草地群落总生物量及克氏针茅、黄囊苔草、冰草地上生物量与氮肥添加没有显著相关关系,冷蒿和星毛萎陵菜地上生物量随施肥量的增加而显著下降.该结果暗示着氮沉降的增加通过影响植物功能性状,进而改变植物群落的构成.本研究加深了我们对氮沉降增加条件下植物响应策略及群落演替机制的理解.

Leaf functional trait response to nitrogen addition of abundant species in an Inner Mongolia Stipa steppe

Increasing nitrogen deposition imposes dramatic effect on plant functional traits,and changes the structure of plant community.To investigate how species nitrogen utility strategy shifts across nitrogen gradient,we conducted analyses of functional traits of 5 abundant species from Inner Mongolia grassland in a six-year nitrogen addition experiment.Increasing nitrogen addition led to increased individual plant height,leaf area,specific leaf area,leaf nitrogen and phosphorus contents,but decreased leaf dry matter content,probably to improve competition for light resources.These results suggest that increased nitrogen addition led the plant investment strategy to change from low to quick return of nutrients and dry mass.Biomass of grassland community,and of Stipakrylovii,Carexkorshinskyi and Agropyroncristatum,showed no corerelation with nitrogen addition, but biomass of Artemisia frigida and Potentilla acaulis significantly decreased upon nitrogen addition.These results suggest that increasing nitrogen deposition had important effect on plant functional traits,and changed the structure of plant community.This study gives a better insight to understand plant response to nitrogen deposition and mechanism of community succession.