不同地下水位处理下的疏花水柏枝种子萌发和幼苗生长特征

Characteristics of Seed Germination and Seedling Growth of Myricaria laxiflora under Different Groundwater Table Treatments

摘要: 目的：土壤地下水位与土壤含水量是影响河岸带植物种群更新的关键因素。疏花水柏枝因三峡工程修建失去了库区所有的生境而成为了一种濒危物种。方法：本文通过模拟不同土壤地下水位，测定了疏花水柏枝种子萌发和幼苗生长对土壤地下水位的响应，以揭示疏花水柏枝残留种群的更新机制。结果：结果表明，土壤地下水位对种子的萌发有着显著影响。种子萌发率随着土壤地下水位的下降而不断增加，−10 cm土壤水位的种子萌发率比0 cm土壤水位高201.8%。土壤地下水位还对幼苗的存活与生长有着显著影响。出苗率、植株鲜重和幼苗长度都随着地下水位的降低而显著增加，−10 cm土壤水位的出苗率、植株鲜重和幼苗长度分别比0 cm土壤水位高108.5%，158.5%和140.7%。结论：综上所述，土壤地下水位对疏花水柏枝的种子萌发和幼苗生长都有着显著影响，进而对种群的更新产生影响。

Abstract: Objective: Soil water table and soil water content are the key factors influencing regeneration of riparian plant populations. Myricaria laxiflora has lost all the habitat in the reservoir and become an endangered species due to the construction of the Three Gorges Project. Method: This article simulates different soil water table and test the responses of M. laxiflora’ seed germination and seedling growth to soil water table to reveal the regeneration mechanism of survival populations. Result: The results show that soil water table has a significant effect on seed germination. Seed germination rate increases with the decrease of soil water table. The highest seed germination rate occurred at −10 cm soil water level treatment increasing by 200.2% contrast to the 0 cm soil water level treatment. Soil water table also influenced significantly the survival and growth of seedlings. The emergence rate, plant fresh weight and seedling length all increased significantly with the decrease of groundwater level. The emergence rate, plant fresh weight and seedling length of −10 cm soil water level treatment were higher than 0 cm soil water level by 108.5%, 158.5% and 140.7%, respectively. Conclusion: Soil water table has a significant effect on seed germination and seedling growth of M. laxiflora, which further affects population regeneration.