枯枝落叶物厚度影响毛红椿种子出苗的模拟研究

Simulation Study on the Effects of Litter Layer Thickness on Seedling Emergence of Toona Ciliata Var. Pubescens

为了探讨枯枝落叶物对毛红椿天然更新的影响,通过室内模拟试验,研究了毛红椿枯枝落叶物厚度及置放位置对其种子萌发及幼苗存活的影响。结果表明:当种子置于枯枝落叶物上时,枯枝落叶物越厚种子萌发时间越晚,一定厚度的枯枝落叶物对幼苗发生有显著促进作用,幼苗茎长变短;当种子被枯枝落叶物覆盖时,枯枝落叶物越厚出苗时间越晚,出苗率随着枯枝落叶物厚度的增加而降低(枯枝落叶物厚度≥2 cm显著降低出苗率),幼苗苗根变短,枯枝落叶物厚度与幼苗生物量呈较弱的负相关。幼苗存活率随枯枝落叶物厚度的增加而显著降低,5 cm厚枯枝落叶物覆盖的幼苗29 d全部死亡。从而说明毛红椿种子萌发在一定程度上受地表枯枝落叶限制,或虽能萌发但幼苗纤弱,自然死亡率较高。建议在毛红椿林分管理过程中,可以适当去除枯落物以促进种子萌发与幼苗生长。

Effects of litter thickness and implantation position on seed germination and seedling survival of Toona ciliata var.pubescens were studied by simulation in laboratory in order to explore the effect of litter layer on natural regeneration .The results showed that the thicker the litter things was ,the later seed germination time was when the seeds were in the litter on .A certain thickness of litter content in seedlings had significant role in promoting and seedling stem length was shorter .The thicker the litter layer was ,the later and lower seedling e-mergence was when litter covered seeds .With the litter layer thickness increased ,the germination rate declined . The seedling emergence rate reduced significantly when litter thickness was greater than or equal to 2 cm.The seedling root length was shorter .Litter layer thickness was weaker negatively related to the biomass .The seed-ling survival rate reduced significantly with increasing of litter layer thickness .The seedlings covering 5 cm lit-ter died after 29 days.The seedling emergence had been restricted for litter to some extent .The nature mortality was higher because of delicate seedling .The seed emergence and seedling on Toona ciliata var.pubescens have improved by removed litter appropriately in future forest management process .