不同放牧强度下草地植物生理变化的研究

The Study on Grassland Vegetation Physiological Responed to Different Grazing Intensities

放牧是草地最有效、最经济的利用方式。草地植被的群落特征,如盖度、高度、密度、生物量、多样性(Shannon-weiner指数)、丰富度(Richness指数)和均匀度(Pielou指数)等随着放牧强度的增加呈现有规律的变化趋势,并在轻度或适度放牧的条件下达到最优化,符合Connell等提出的"中度干扰假说"的发展规律,而草地植物通过调解资源的重新分配、光合作用和渗透、内源激素等方式,促进植物降低高度、改变生殖方式、提高资源的利用率、积累更多的内含物质和抗逆激素,增加对采食的耐受性,以提高种群的生存和竞争能力,形成对放牧压力的进化对策,以保证种群的延续。但是由于受到气候、土壤及季节等多方面因素的影响,不同的研究背景下,草地植被的生理变化与群落特征之间的变化关系产生差异。因此,关于不同放牧强度下草地植物的生理指标与植被群落特征之间的关系,还需要进一步的研究和探索。

Grazing is the most effective and economical ways of using grassland.On the one hand,grassland vegetation community characteristics,such as Coverage 、 Height 、 Density 、 Biomass 、 Shannon-weiner index、 Richness index、Pielou index change regularly under the influence of grazing intensity,accord with the ＂intermediate disturbance hypothesis＂,on the other hand,grassland plant promote themselves to reduce height,change reproductive mode,improving the resources utilization,accumulate more contains material and stress resistance hormone by the reallocation of resources,photosynthesis and penetration,endogenous hormone,etc,so they can increase the choice of tolerance,improve population survival and competition ability,forming the grazing pressure evolution countermeasures,in order to ensure the continuation of the population.But due to climate 、 soil and seasonal etc.various factors,people produce difference research achievements under different research background,so,the relationship between different grazing intensities of grassland plant of physiological indexes and vegetation community relationship need for further research and exploration.