温性草甸草原羊草功能性状对不同放牧强度的响应

Response of functional traits of Leymus chinensis to different grazing intensities in temperate meadow grassland

摘要:

【目的】研究锡林郭勒盟温性草甸草原建群种羊草(Leymus chinensis)茎叶性状在羊放牧干扰下的响应机制和相关关系。【方法】设置四个不同放牧强度(禁牧、轻度放牧、中度放牧、重度放牧)处理，测定锡林郭勒盟温性草甸草原羊草个体生长特征性状，量化分析羊草茎叶对不同放牧强度的响应， 研究其关系、变化规律及其影响因素。【结果】随着放牧强度增加，温性草甸草原羊草重要值下降，植株出现矮小化，其株高、单株重、叶片数、叶宽和总叶面积减少；羊草地上生物量与株高、茎干重、叶干重和总叶面积显著正相关，而与叶片数无显著相关。轻度和中度放牧对羊草叶长有促进作用，而重度放牧对叶长有抑制作用。轻度放牧增加羊草比叶面积，中度放牧与禁牧比叶面积相差较小，但重度放牧时比叶面积显著减少。【结论】Corner 法则同样适用于草原植物，轻度、中度放牧下叶性状较为敏感，并出现补偿现象，重度放牧下个体生长特征性状较为敏感。

Abstract:

【Objective】 This study aims to investigate the response mechanism and correlation of stem and leaf characters of Leymus chinensis in temprate meadow grassland of Xilin Gol League under the disturbance of sheep graz‐ ing.【Method】 Four grazing intensities (no grazing，light grazing，moderate grazing and heavy grazing) were set up to measure the individual growth characteristics of Leymus chinensis in the temperate meadow grassland of Xilin Gol League. The responses of stems and leaves of Leymus chinensis to different grazing intensities were quantitatively ana‐ lyzed，and the relationships，changes and influencing factors were studied.【Result】1)The important values of Ley- mus chinensis decreased with increasing grazing intensity. The plants appeared to be dwarfed；the plant height，single plant weight，leaf number，leaf width and total leaf area decreased. Aboveground biomass of Leymus chinensis was sig‐ nificantly and positively correlated with plant height，stem dry weight，leaf dry weight and total leaf area but was not significantly correlated with leaf number. Light and moderate grazing exerted a positive effect on Leymus chinensis leaf growth，while heavy grazing had an inhibiting effect on leaf growth. 2) Light grazing increased the specific leaf area of Leymus chinensis. Moderate grazing had little difference with no grazing，but heavy grazing significantly re‐ duced the specific leaf area.【Conclusion】 Corner's Law was also applicable to grassland plants. Leaf traits were more sensitive under light and moderate grazing，and compensation phenomenon occurred，while individual growth charac‐ teristics were more sensitive under heavy grazing.