A PRELIMINARY STUDY ON THE SOIL SEED BANKS OF DIFFERENT SUCCESSIONAL STAGES OF SUBTROPICAL EVERGREEN BROADLEAVED FOREST
亚热带常绿阔叶林不同演替阶段土壤种子库的初步研究

The successional series of subtropical evergreen broadleaved forest in Jinyun Mountain of Sichuan province has been divided into six stages in this paper. They are: (1) old-field; (2) shrub grassland; (3) masson pine forest; (4) evergreen needle and broadleaved mixed forest dominated by masson pine; (5) needle and broadleaved mixed forest dominated by evergreen broadleaved species; (6) evergreen broadleaved forest. Five 0.5m~2 soil sample measured 10cm high from each of six stages were taken to laboratory to let seeds in the soil germinating. From the appearance of seedlings, we concluded followings: A. At the early stages of succession (from old-fieds to masson pine forest), the number of seeds and species diversity decreased with the development of succession. In these stages, the deeper the soil stratification is, the less the number of seeds is. At the later stages of succession(from masson pine forest to evergreen broadleaved forest), the number of seeds is increased with succession evolution. In different stratification of same stage, the number of seeds is nearly the same. B. Most of seeds in different stages are herb species. C. If humidity and light is fixed, the number of germinated seeds is interrelated with temperature. More than 80% seeds of most species are germinated in six weeks. D. The species composition between above ground vegetation and soil seed banks are nearly the same at the early stages of succession, but it is very different in the later stages.The sampling volume of soil seed banks and the signification of soil seed banks in vegetation succession have also been discussed in this paper.