Study On The Sexual Reproduction And Survival Strategy Of The Quercus Variablis Population In North Slope Of Qinling Mountains

Quercus variabilis Bl. is widely distributed in 22 provinces in north, central, sorth and southeast China and also is the constructive species of zonal vegetation in deciduous broad-leaf forest of warm-temperate region. In this research, based on several approaches as fiel investigation, control experiment and mathematic analysis, the reproduction process of Quercus variabilis is discussed, which mainly contains: reproductive phonology, seed rain, seed bank and seedling bank characteristics. The results are as followed:1) The population structure from the North Qinling Mountain Slope (Louguantai, Tangyu) shows progressive type, and the static life table shows that the mortality rate of annual to three-year-old individuals is high. The survival curve shows Deeveyâ…¢. With the increase of diameter class, the mortality rate shows the trend of"high-low-high".2)Q. variabilis seedling forest start the first reproductive activity at 7~9a, while the sprout forest started at 5~6a. There are differences in phonology and reproductive ability between forests at different age. The young forest exceeds the old forest. Sunlight is the most influential factor to anthesis and fruit.3) Seed rain of Q. variabilis started in late August and ceased in mid October. There are three types seeds in the seed rain: viable seed, immature seed, and seed infected by larvae. Seed infected by larvar takes up the most percentage of the whole(56.8%). Mean seed rain density at rush period is 16.8 ind/ m~2.4) Seeds in soil seed bank are classified into 6 types: viable seed, immature seed, seed infected by larvae, decayed seed, budding seed and predated seed. Ratio of six types changes in the whole process. Density of seed bank reaches its peak a few days after the peak of seed rain. Predation and infection are the two major way of seed bank loss. Human disturbance and mammals predation activity are correlative. Seed budding probability in the wild is low(5.4%).5) There are considerable discrepancy in seedling density among three different habitates. The distribution pattern of seedlings switches from colony distribution to random and well-distributed as the age level rised. Biomass of aboveground and underground differs, but the difference become weaker when the age level rises.