西双版纳热带森林土壤种子库的季节变化

Seasonal soil seed bank dynamics in tropical forests in Xishuangbanna

通过萌发实验法对西双版纳地区的一类热带季节雨林 (番龙眼、千果榄仁 )和 2类次生林(白背桐林、中平树林 )的土壤种子库的季节变化进行了探讨。结果表明 :该地区的土壤种子库动态具有明显的季节性。季节雨林的土壤种子库储量相对稳定 ,土壤上层 ( 0～ 2 cm )的种子储量在雨季末期较大。2类次生林土壤种子库的变化则相反 ,土壤种子库中的种子种类在旱季末期较雨季末期多 ,土壤上层的种子储量在旱季末期较大。各样地均有一些种类只出现在旱季末期或雨季末期。种子在土壤种子库的动态与植物的繁殖物候和所处的环境紧密相关 ,不同种类植物的土壤种子库由于植物本身的生物学特性。

Seasonal dynamics in soil seed bank was studied using germination trials in tropical forests in Xishuangbanna. Twenty soil samples were taken from a seasonal rain forests and two secondary forest dominated by Macaranga denticulata and Mallotus panculatus at the ends of two dry and rainy seasons respectively. The seasonal changes in seed storage, species composition and seed distribution in soils in the three forests were analyzed. The seed storage of two secondary forest sampled at the end of dry season was higher than that sampled at the end of rainy season, and more species presented at the end of dry season. Seed in the upper layers of soil in the two secondary forests tended to the same trends. In Contrast, the seed storage of seasonal rain forest sampled at the end of rainy season was higher, with more species presented in the upper soil layer. The seasonal changes of some dominated species in soil seed banks was also studied in this paper.