Seed Germination Characteristics Of Woody Plants In The Eastern Qinghai-Tibet Plateau

In a long time, most of researches on germination ability of seed have been concentrated on the same species.Furthermore, most comparison in seed germination among species only limited to compare among several species or within a genus, and the comparative studies on seed germination and dormancy in a whole community were much less.But the comparative results derived from one or several species did not account for the ecological significance of seed germinability.In addition,the studies reported on seed germination with a community were done in tropical or temperate zone,and there was not investigation on meadow wood.We expected to provide the basic theoretic evidence by our study on discuss the species composition and dynamic of ecosystem in the eastern Qinghai-Tibet plateau.The result showed: 1) The germination patterns of these species were classified into four types by Principal Component Analysis and Cluster Analysis: rapid, intermediate, slow and low. A greater proportion of dominant species had intermediate and slow germination than rapid and low germination; the common species had similar proportions of intermediate, slow, and low germination, but only 3.32% with rapid germination. The proportion of species with rapid germination was slightly greater for dominant species than common species, and proportion with low germination was less than in common species. 2) For 43 shrub species: there were significant negative correlations between germination percentages, germination rate and seed size; but days to first germination and duration of germination were weakly related to seed size.For 64 speces under 20℃geminated: germination percentages, germination rate were weakly related to seed size. 3)there were significant difference in percent germination among temperature.The highest percent germination and higher germination rate at 5/25℃, Higher percent germination and the highest germination rate at 20℃, Higher percent germination and lower germination rate at 10℃, lower percent germination and germination rate at 15℃and 25℃.The highest dormant at 15℃and 25℃,while the lowest dormant at 5/25℃. 4) There were significant difference in seed germinability among habitats. Species from south slope boscage had the highest percent germination and germination rate,and species from north slope boscage had the lowest. percent germination and germination rate.Species from alpine boscage had the highest dormant proportion of species,and species from south slope boscage had the lowest domant proportion of species. 5) There were significant difference in seed germinability among altitudes. there were significant negative correlations between germination percentages and seed size, weakly related between germination rate and seed size.The mean altitude of dormant species was slightly heavier than the mean altitude of non-dormant species. 6) There was not significant difference in seed germination and germination rate among classes. There was not significant difference in seed germination and significant difference in germination rate among families.7) For the 22 species: The percent germination of embedding species was slightly higher than the percent germination of the room storage species. There was significant difference in germination rate between two storages. For the 64 species under 20℃germinated: There was no difference between the embeddings and the room storage species.