氮素添加对羊草非结构性碳水化合物和脯氨酸的影响

Effects of Nitrogen Addition on Non-structural Carbohydrates and Proline in Leymus chinensis

为探究施肥对羊草(Leymus chinensis)非结构性碳水化合物(NSCs)和脯氨酸(PC)的影响,以内蒙古呼伦贝尔草甸草原为研究对象,分析群落优势物种羊草NSCs各组分对两种氮素化合物(尿素和硝酸铵),5个氮添加梯度(0、2、10、20、50 g N·m^(-2)·yr^(-1))的响应规律与机制。研究结果表明:相对于尿素添加,羊草NSCs各组分对硝酸铵的响应更为敏感,且在降水较多的年份响应更为明显;施氮提高了羊草叶片的PC含量,其中在低浓度氮素添加水平(≤10 g N·m^(-2)·yr^(-1))下,其含量增幅更大,氮素添加水平高于10 g N·m^(-2)·yr^(-1)增幅不显著;在两年间降水较少的年份,PC对氮添加梯度增加的响应更为敏感;不同处理下,羊草的相对生物量与其淀粉(ST)含量、PC含量均呈显著正相关关系。该研究证实羊草叶片可以通过PC的调节来应对氮沉降,PC的升高对其NSCs及其组分生长具有正效应。

In order to explore the effects of fertilization on non-structural carbohydrates(NSCs)and Proline(PC)in Leymus chinensis,this study took Hulunbuir meadow grassland in Inner Mongolia as the research object,selected Leymus chiueusis as the test plant,and analyzed the response patterns and mechanisms of urea and ammonium nitrate under the application of five concentration gradients(0,2,10,20,50 g N·m^(-2)·yr^(-1))through simulated nitrogen deposition experiments.The research results show that leymus chinensis was more sensitive to ammonium nitrate compared to urea addition.The NSCs and its components of the plants were higher in the year of high precipitation.With the addition of nitrogen compounds,the PC content of Leymus chinensis leaves increased.At low concentration nitrogen addition levels(≤10 g N·m^(-2)·yr^(-1)),the increase in its content was greater;while the increase was not significant when nitrogen addition levels were above 10 g N·m^(-2)·yr^(-1).In the years with less precipitation,PC was more sensitive to the gradient increase of nitrogen addition.The relative biomass of leymus chinensis was positively correlated with its starch content and PC content.This study confirmed that the leaves of Leymus chiueusis can cope with nitrogen deposition through the regulation of PC,and the elevation of PC have a positive effect on its NSCs and their components.