不同沙埋深度对当年生柠条锦鸡儿种子萌发及幼苗生长的影响

Effects of sand-burying on seed germination and seedling growth of Caragana korshinskii Kom

在自然条件下设置1、2、3、4、5 cm和6 cm 6个沙埋深度处理,对柠条锦鸡儿种子萌发和幼苗生长进行了全生长季观测,以说明种子成熟当年不同沙埋深度下柠条锦鸡儿种子萌发,幼苗存活情况以阐述实现种群更新的机理。结果表明：柠条锦鸡儿种子萌发率随着沙埋深度的增加呈减小趋势,萌发最佳沙埋深度为1 cm,萌发率为55%,当沙埋深度增加到4-6 cm,萌发率降低到4%-6%;种子萌发天数随着沙埋深度的增加而增加;幼苗存活率随着沙埋深度的增加而增加,1-4 cm沙埋深度出土幼苗存活率为50%-58%,而6 cm柠条锦鸡儿出土幼苗存活率为100%。对于当年生柠条锦鸡儿种子,1 cm沙埋深度下种子产生的自然更新最大,25%的种子可以萌发并成功产生更新,而随着沙埋深度增加,大部分当年生种子不能萌发而进入土壤种子库,当沙埋深度达到6 cm时,96%的种子进入土壤种子库,这对于种群更新和土壤种子库补给有重要的作用。

Caragana korshinskii Kom is an important shrub species widely used for vegetation rehabilitation in northern China. The controlled experiment was conducted to test the effects of sand-burying on the seed germina- tion and seedling emergence and growth of Caragana korshinskii Kom in a typical add desert region under nature conditions after the seeds mature. Six treatments of sand-burying of depths 1,2,3,4,5 and 6cm were designed and each treatment included five replicates. In the burial experiment, seedling emergence declined with sand burial depth：the optimal burial depth of Caragana korshinskii Kom is lcm and the seedling emergence rate was 55%; at 4-6 cm, the seedling emergence rates were 4%-6%. The seedling emergence time increased with increasing sand-burying depth： at lcm the seedling emergence time was 2 days; at 5-6 cm, the seedling emergence time were 29-30 days. The seedling survival rate increased with increasing sand-burying depth： at 1-4 cm the seedling survival rates were 50%-58% ; at 6cm, the seedling survival rates reached 100%. Seedling sizes were noticeably affected by the depth of sand burial due to the emergence time. The deeper sand burial was the smaller seedling was. lcm was the optimal depth for Caragana korshinskii Kom to emerge and 25% mature seeds can develop into seedlings in the first year. However, with increasing sand-burying depth a greater ratio of mature seeds supplied the soil seed bank. At 6 cm, 96% mature seeds supplied soil seed bank. In a restoration context, suitable species that are vulnerable during emergence and establishment can be targeted, and plant species, seedling growth rate and sand burial depth are determinants of recruitment success for desert species.