内蒙古典型草原不同放牧强度下羊草光合生理生态特性分析  

Photosynthetic Ecophysiology Characteristics of Leymus chinensis under Different Grazing Intensities in Inner Mongolia Steppe

作　　者：米雪[1] 李晓兵[1] 王宏[1] 黄奇[1] 白云晓 

机构地区：[1]北京师范大学资源学院/地表过程与资源生态国家重点实验室,北京100875

出　　处：《中国草地学报》2015年第3期92-98,共7页Chinese Journal of Grassland

基　　金：国家重点基础研究发展计划课题--草原植物对放牧的生理生化响应机制(2014CB138803);长江学者和创新团队发展计划资助;国家国际科技合作专项资助

摘　　要：通过对内蒙古典型草原不同放牧强度下羊草光合日动态、叶绿素荧光参数以及光合生理生态指标的测定,分析探讨了放牧对羊草光合及生理生态特性的影响。结果表明:羊草净光合速率、蒸腾速率、气孔导度随放牧强度的增大而增大,T2放牧强度下羊草光合日动态为双峰曲线,出现"午休现象",非气孔因素是主要原因;叶绿素荧光参数Fv/Fm三种处理间差异不显著,ΦPSII、qP、ETR三种参数随放牧强度的增大而增大,T2放牧强度下的值显著大于T0和T1;T1放牧强度下羊草相对叶绿素含量显著小于T0和T2,叶干物质含量则相反,比叶面积和干物质含量二者呈负相关关系;羊草叶片数、叶片长度随放牧强度的增大而下降。由此表明,适度放牧有助于羊草光合作用,叶片形态出现缩小特征,以适应放牧干扰。The grazing effects on the photosynthetic ecophysiology characteristics of Leyrnus chinensis were studied, the diurnal dynamics of photosynthetic, chlorophyll fluorescence parameters and other physiological and ecological indicators of Leymus chinensis in Inner Mongolia steppe under different grazing in- tensities were investigated. The results showed that the net photosynthetic rate, transpiration rate and stomatal conductance of Leymus chinensis increased with grazing intensities, photosynthetic diurnal dynamics of Leymus chinensis under T2 grazing intensity showed a double-peak curve, appeared midday de- pression of photosynthesis, the non stomatal factors were the main reasons. Differences of Fv/Fm between the three treatments was not significant, while the other three chlorophyll fluorescence parameters, φPSII, qP and ETR, increased with grazing intensities, the parameters under T2 were significantly grea ter than TO and T1. The relative chlorophyll content of Leyrnus chinensis under T1 was significantly lower than TO and T2, leaf dry matter content was the opposite, and there was a negative correlation between specific leaf area and dry matter content. Leaf numbers and leaf length of Leymus chinensis decreased with grazing intensilies. This showed that moderate grazing helped photosynthesis of Leymus chinensis, leaf became smaller to accommodate grazing disturbance.

关 键 词：羊草 放牧强度 光合 叶绿素荧光 

分 类 号：S543.9[农业科学—作物学]