| Arundinella hirta and Leymus chinensis are typical clonal plants with rhizome, which have large ramets and amount of rhizomes. They always form dominant community in the meadow steppe of the Songnen Plains, China. By using the method of excavating samples in unit area, A. hirta and L. chinensis populations in different habitats were investigated in2012and2013. Experiments were conducted on the structure and interactivity of A. hirta and L. chinensis populations in dominant and mixed community to help to predict change of A. hirta populations during restoration succession.The results showed that, spring ramets and rhizome buds of A. hirta populations had advantages at the beginning of the growing season in meadow habitat, while their winter ramets and buds of tillering node were dominant in mowing steppe. Winter ramets and rhizome buds of L. chinensis populations had advantages, which output rate of bud banks higher than A. hirta populations. Quantity allocation of each modular was vegetative ramets>reproductive ramets> seedling in the beginning of growing season on A. hirta populations, and was seedling> vegetative ramets reproductive ramets in the end. Biomass allocation overall was reproductive ramets>vegetative ramets> seedling in four plots. L. chinensis populations had few reproductive ramets in2012, the number and biomass of vegetative ramets were higher then seedling. Ramets structure of A. hirta populations was stable, composing of2-3age classes. The proportion of number on1a ramets was53.0%-90.8%, and of biomass on1a ramets was77.1%-96.4%. Changes of number and biomass of A. hirta ramets were dependent on first age class in each plot. The number of ramets increased with time, and reached the maximum value at the end of the season. Variation trend of biomass were same in different plots of the same year. Ramets of L. chinensis populations composed of3age classes. The rhizome of two populations composed of3-4age classes and the second age were dominant in length and biomass. Growth ability of1a rhizome was strong. Seasonal change of biomass and length about rhizome were consistent. In this experiment, the index of productivity means biomass of one hundred ramets. The1a ramets generally had higher productivity than other ages in two populations, and reached the maximum in July or August, which1.81-11.99times than that of2a ramets in A. hirta populations, and which2a rhizomes had higher storage capacity than1a, but there weren’t significant different among plots. P4had stronger growth ability compared with other plots on various measures of buds. In general the ratio of tillering buds higher than rhizome buds, the latter had dominant in P1and P2, but the former had partly ascendant trend in P4and P5. The change of tillering buds were different in plots. There had the same change on rhizome buds in two years, which growing during June and August, and shrinking during August and October in P1and P2. The rhizome buds continued increasing during the growing season and reached the maximum in the end. The ratio of rhizome buds higher than tillering buds in A. hirta populations. There had significant positive linear correlation between A. hirta and L. chinensis populations in term of ramets number, ramets biomass, vegetative buds, rhizome length and rhizome biomass in mixed community. Two populations were competitive and have possibility to become the dominant in mixed community. |
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