松嫩平原大针茅群落种子雨动态的研究

THE STUDY ON SEED RAIN CHANGE OF STIPA GRANDIS COMMUNITY IN THE SONGNEN PLAIN OF CHINA

根据1982-1988年连续7年野外定位观测资料,定量分析了大针茅群落的种子雨动态及其与水、热气侯因子的关系。在大针茅群落的种子雨中,总共出现了46种植物,其中有9种为恒有种。优势种大针茅的种子雨密度仅占各年度种子雨总密度的0.3-1.3%。双子叶植物类群的种子雨密度比单子叶类群普遍高1.5-13.5;多年生植物类群1985年以前比一年生类群高0.2-7.4倍,1986年以后则低0.4-1倍。在种子雨的植物生活型谱中,各年度多以地面芽植物的比率最大。一些植物类群和恒有种群的种子雨密度与生长季前、中期的日照时间、积温、降水量及前一年度生长季不同时期的降水量呈不同程度的正相关。

In light of the field-investigation at the fixed position from 1982-1988, a quantitutive analysis was done on the change of seed rain,and the relationships between the seed rain and water-heat climaticfactors in Spipa grandis community was discussed in this paper.There we-re 46 plant species altogether and 9 of which were constant species inthe seed rain of the community. The density of S. grandis which is domi-nant species was only about 0.3-1.3% in the total density of the seedrain every year. The seed rain density of dicotyledon group was generallyabout 1.5-13.5 times higher than that of the monocotyledon group, andthe perennial group were 0.2-7.4 times higher before 1985, but 0.4-1.0times lower after 1986 than the annual group in the community. The rati-os of hemicryptophytes were usually the highest in life form spectrum ofthe seedrain plants every year. There was positive correlation of differentvalue between the seedrain densities of both some plant groups and con-stant populations and the sunshine hours,the accumulated temperature,therainfall in the earlier-middle growing season,and the rainfall in differentperiods preceding growing season respectively.