濒危植物缙云卫矛不同种群的种子萌发研究

Seed Germination Characters of Populations of the Endangered Plant Euonymus chloranthoides

选取重庆特有濒危植物缙云卫矛7个相互间有不同程度空间隔离的种群,对其种子萌发特征进行研究。结果表明:7个种群的种子在实验室条件下萌发率差异极显著,种子萌发率与所处种群的大小呈极相关,大种群与小种群的种子萌发率差异达极显著水平,而各种群的种子萌发率与其所处生境的土壤因子相关性不显著。各种群的平均种子质量与种群大小及土壤条件均无关,说明种群平均种子质量是一个较为稳定的不易受影响的参数。小种群低萌发率的主要原因可能是由于近交衰退带来遗传多样性的丧失引起的,而不是环境因素的影响。研究表明:要长期保护这些小种群,应将种群统计因素与种群遗传因素结合起来考虑,增加种群中个体数目,扩大种群,提高种子萌发率,促进种群更新,才能有效地维持这些小种群的生存发展。

Seed germination characteristics of 7 spatially isolated populations of the endangered plant Euonymus chloranthoides were studied in the laboratory condition. The differences of the seed germination rates among 7 populations were found to be extremely notable. The seed germination rates of the studied populations are positively correlated with their population sizes, while show no correlation with the soil parameters. The differences of the seed germination rates between big populations and small populations reach the extremely notable level. The average seed mass of 7 populations are not copiously correlated both with their population size and with soil parameters in the habitats, which indicates that the average seed weight of a studied population is relatively stable and less influenced. The low seed germination rate in smaller populations may mainly due to the inbreeding depression, and/or loss of genetic diversity in the isolated, smaller populations, while not due to the environmental factors. The study suggests that we should take both the non-genetic, demographic factors and the genetic factors into consideration and enlarge the population to maintain higher seed germination rate and restore the normal regenerations among the smaller and isolated populations of this endangered plant.