三峡地区柏木种子萌发和幼苗更新的研究

Seed Germination and Seedling Recruitment of Cupressus funebris in the Three Gorges Area，China

摘要:

对三峡地区柏木(Cupressus funebris)林柏木种子的萌发、幼苗存活、幼苗生长进行了实验研究，得出如下主要结论：(1)柏木种子的萌动期约为10 d，播种35-45 d后进入萌发高峰期，柏木种子的平均萌发率为47.7%。土壤基质对种子萌发的影响是极显著的，光照对萌发则没有显著的影响。(2)幼苗平均死亡率为52.6%。土壤类型和光照强度对幼苗的存活都有显著影响，以林下土和80%光照条件下幼苗的存活率最高。 (3)柏木幼苗生长初期茎的生长动态呈“S”型，而叶片数量的增长动态近于直线型。幼苗生长初期生物量形成主要受光照条件的影响，土壤类型的影响不显著。土壤和光照条件对柏木林柏木幼苗的更新都有显著影响，但是土壤条件主要影响种子萌发和幼苗的存活，而光照条件则主要对幼苗的生长和存活产生影响。

关键词:种子萌发; 幼苗更新; 幼苗存活; 土壤类型; 光照

Abstract:

Seedling recruitment has important influences on population stability and community succession. Cupressus funebris forest，a secondary community widely distributed in the Three Gorges area, China, plays an important role in environmental protection. Effects of soil and light on seed germination, seedling survival and seedling growth were investigated in C. funebris to elucidate the pattern of seedling recruitment in the Three Gorges area. Seeds began to germinate 20-30 days after seedling, and the germination peak appeared 35-45 days after seeds were seeded. The average germination percentage was 47.7%. Soil substrate had significant effects on seed germination. However, the effect of light on seed germination was not significant. The average mortality rate was 52.6% in seedlings. Both the soil type and light remarkably influenced seedling survival. The lowest mortality occurred in seedlings on forest soil and under 80% light condition. The stem growth of C. funebris seedling showed an “S” pattern, whereas leaves augment was in a linear pattern. The seedling growth and biomass accumulation were affected significantly by light. Seedling biomass increased with light intensity. The biomass allocation of C. funebris seedling was also analyzed to elucidate the relationship among different seedling parts.

Key words:Seed germination; Seeding recruitment; Seedling survival; Soil type; Light