Biological Responses Of Caragana Microphylla To Different Grazing Intensities

Although plants can't move away from the attacks of herbivore, they are not completely subject to the herbivore. In the long evolutionary history, some plants have developed certain defense mechanisms against their predators and parasites. The adaptive mechanisms of host plant to grazing are the key to keep their living and their population multiplication. It is helpful to manage and utilize grassland if we can understand the effect of herbivore on host plant. We hope this information is helpful to conserve the biodiversity and utilize rationally the resource of grassland.A legume shrub, Caragana microphylla which randomly distributed the grazing experimental field of the Inner Mongolia Grassland Ecosystem Research Station was selected to study the biological response to grazing through many ways, such as morphology, application sheep saliva, sexual reproduction, seed germination and genetic polymorphism. According to the experiments, we found four results:1. Long grazing history had significantly influenced the characteristics of morphology and reproduction of C. microphylla under different grazing intensities. Under grazing treatments, there were trade-offs among vegetative, reproductive growth and physical defense. With increasing browsing intensity, the host plants decreased their investment in vegetative growth and reproduction, and increased investment in physical defense organs, as well as, individual miniaturization, decrease of pods and ripe seeds, increase of spine density and length. Additionally, the pollen quality was negatively influenced...