羊草功能性状和地上生物量对氮素添加的响应

Response of Leymus chinensis functional traits and aboveground biomass to nitrogen addition in Songnen grassland in northeast China

植物功能性状对资源变化的适应策略是生态学研究的基本问题之一。本研究在不同氮添加梯度处理下,测定了羊草(Leymus chinensis)的11个功能性状和地上生物量的变化。结果表明,氮添加显著影响羊草的叶片叶绿素a和b含量、叶片类胡萝卜素含量、叶片氮含量、叶片干物质含量和比根长(P<0.05),而对叶片磷含量、比叶面积、叶片厚度、比茎重和植株高度没有显著作用(P>0.05);叶绿素a和b含量、类胡萝卜素含量、叶片氮含量、叶片干物质含量、比茎重和比根长之间有显著的相关关系(P<0.05),比叶面积、叶片厚度和植株高度与其它功能性状的相关性不显著(P>0.05);20 g·m^(-2)的氮添加处理下,羊草地上生物量最高;羊草地上生物量随叶绿素a和b含量、类胡萝卜素含量、叶片氮磷含量、株高的增大而显著升高(P<0.05),随叶片干物质含量、比茎重的增大而显著降低(P<0.05)。

The adaptive strategy of plant functional traits to resources change is one of the basic problems in ecology. In the present study,11 plant functional traits and aboveground biomass of Leymus chinensis with different amount of nitrogen addition were determined. The results showed that nitrogen addition had significant effects on leaf chlorophyll a（ Cha）,chlorophyll b（ Chb） and carotenoid（ Cad） content,leaf nitrogen concentration（ LNC）,leaf dry matter content（ LDMC）,and specific root length（ SRL）,however,had no effects on leaf phosphorus concentration（ LPC）,specific leaf area（ SLA）,leaf thickness（ LT）,stem specific density（ SSD）,and plant height（ PH）. There were significant correlation between Cha,Chb,Cd,LNC,LDMC,SSD and SRL. SLA,LT and PH had no significant correlation with other functional traits. The aboveground biomass of L. chinensis was the highest at 20 g·m^（-2） nitrogen addition.The aboveground biomass significantly increased with Cha,Chb,Cad,LNC,LPC,and PH increasing,but significantly decreased with LDMC and SSD increasing.