黄土丘陵沟壑区退耕地土壤种子库特征与季节动态

The character and dynamics with season of soil seed banks in abandoned croplands of loess gully region

采用野外样线取样与室内萌发相结合的方法研究了黄土高原丘陵沟壑区退耕地种子库的组成、密度、分布特征、季节动态、种子库类型。结果表明,土壤种子库中共发现50种植物的种子,隶属15个科,39个属,主要物种组成与密度季节间差异不显著;在演替过程中土壤种子库的物种数量与密度随退耕年限的增加表现出：增加-减少-增加的趋势,同时阳坡种子库密度波动较阴坡剧烈;土壤种子库密度年内变化范围为1 067-14 717粒/m^2,土壤种子库平均密度是夏季〉秋季〉春季;研究区域退耕地土壤种子库类型属于以猪毛蒿为优势种,并具有其他一年生、多年生草本植物与灌丛种子的没有显著的季节动态的持久种子库,是物种适应黄土丘陵沟壑区特有生态环境条件的繁殖更新策略;从土壤种子库的物种组成、密度、类型来看,黄土丘陵沟壑区退耕地具有一定的自然恢复潜力。

Samples were collected along two 10 m sections and a germination experiment was carried out in the laboratory to investigate the composition, density, type, and distribution at different times and spaces of the seed bank. There were 50 species belonging to 39 genera and 15 families in the soil seed bank. The density and composition of the main species in the bank were not significantly different between seasons. During the succession, the number of species and the density of the bank initially increased, then declined, and finally increased again. However, the seed bank density changed more acutely during the year, ranging from 1 067 to 14 717 seed/m^2 , with the maximum value in summer, the medium in autumn, and the minimum in spring. The soil seed bank in the study field was persistent with Artemisia scoparia the main species coexisting with other annual vegetation, perennials and shrubs. Additionally, in the field, the soil seed bank did not change notably with the season. There is some potential for vegetation restoration using the soil seed bank.