Study On The Biological Characteristics Of Cenchrus Calyculatus Cav.

Biological invasion seems more and more common resulting from the activities of human beings and global change. The biological invasion has got great attention from all over the world because of its huge harm. Cenchrus calyculatus belongs to Gramineae, it usually distributes in the subtropical areas, while recently it appears in some regions of Tongliao, Inner Mongolia and spreads extensively, harmful to local ecosystem. Cenchrus calyculatus works as an invasive plant of Inner Mongolia. There are few researches focusing on this species in the world, this dissertation studies its germination characteristics and its effects in different plant communities, aiming to contribute to subsequent researches on its invasive mechanism.The shape of its seed is half-sphere alike and the surface is smooth. The appropriate temperature for the germination of Cenchrus calyculatus is 20-25℃, the number of seedling increases more quickly in pure sand, the stepwise extending of seed-buried depth arranging from 1.5 to 6.0 cm does not have obvious effect on the number of seedling. The basal part of the renascent seedling is mauve. According to the important value, the effect of Cenchrus calyculatus is tiny in the community type L,C,S,P. However, in the plant community of type J, this species owns centralizing distribution, the relative coverage reaches about 0.9, the important value is 1.9, possessing absolute superiority. The Shannon index of community type J is highest, which means 0.61, and the evenness index of type J is 0.26, also the simplest one. The invasion of Cenchrus calyculatus has no apparent effects on the variety of soil factors. In addition, it is necessary to combine the field investigation with transplanting experiment to analyze the relation between the plant species and the soil of invaded plant community. In the long term, it will be more effective to minimize the harm of this invasive species by strictly preventing the diffusing of its weeds.