Study On Reproductive Characteristics Of Several Representative Rhizomatous Grasses

Through consulting literature, field survey, this paper studied on vegetative reproductive categories and their expansion capability of common perennial plants in Inner Mongolian steppe, and selected Pennisetum centrasiaticum, Leymus secalinus and Bromus ircutensis three typical rhizomatous grasses to research. Compared and analyzed pattern of growth, characteristics and ability of vegetative propagation and sexual propagation of rhizomatous grasses, including Leymus chinensis, Poa pratensis, Bromus inermis, Psammochloa villosa, Carex duriuscula and two tufted grasses: Agropyron cristatum, Elymus sibiricus. The results were listed as below:1.According to the origination of vegetative reproductive organs, common perennial plants in Inner Mongolian steppe were classified into different vegetative reproductive categories. including root tillering type, rhizomatous type, bulb reproductive type and stolonous type etc. Different categories had different propagation ability and expansion capability. It was : rhizomatous type which had long rhizome > root tillering type and stolonous type> bulb reproductive type and rhizomatous type which had short rhizome> tufted grasses.2.According to the internodes, rhizome grasses were classified into long and short two rhizomes types. Leymus secalinus, Bromus ircutensis and Leymus chinensis are belonging to long rhizomes plants;Poa pratensis, Bromus inermis and Carex duriuscula are short rhizomes plants,. And Pennisetum centrasiaticum fall in between. Accordingly, pattern of growth of rhizome grass can be classified into two categories, Guerilla growth form and Phalanx growth form. Leymus secalinus Bromus ircutensis Leymus chinensis are belonging to Guerilla growth form, Poa pratensis,Bromus inermis and Carex duriuscula are belonging to Phalanx growth form, Pennisetum centrasiaticum existed simultaneously in two forms.3.Under the natural condition,vegetative propagation of three rhizome grasses Pennisetum centrasiaticum, Leymus secalinus and Bromus ircutensis have their own characteristics. The variety of the rhizome buds and their mature plants were unregular. vegetative propagative ability of Pennisetum centrasiaticum was better than other two grasses. Accord to the vegetative growth impact, After being Cut off the roots of the grass, Pennisetum centrasiaticum strongest survived, the death rate of rhizome buds of Leymus secalinus was higher, but had a less influence to its plant division. After being cut the roots, both rhizome buds livability and plant division of Bromus inermiskept at a low level.4.The ability of sexual reproduction of rhizomatous grasses are relatively weak, but constraining factors are vary.,Pennisetu is the seeding growth, .The main cause of Leymus secalinus is seed dormancy, and Bromus ircutensis is because of low seed yields. The vegetative propagation dominated in rhizomatous grasses. So vegetative propagation should be the main way to achieve population reproduction and renovation,in the natural vegetation.