珍稀植物伯乐树一年生更新幼苗的死亡原因和保育策略

伯乐树（Bretschneidera sinensis Hemsl.）是我国特有的珍稀植物，一年生幼苗的高死亡率是其濒危的主要原因之一。本文采用分区试验探讨了幼苗死亡的原因；并研究了酸碱度和遮荫对其生长的影响。结果表明伯乐树根系无根毛，不同的育苗方式对幼苗存活率有显著区别；造成其死亡的主要原因是根系腐烂、干旱胁迫和害虫捕食等；幼苗适于弱酸性土壤（5.0~6.5）；中等郁闭度的林下自然遮荫或大田中遮网1层均有利于幼苗的生长，若过于荫蔽会导致生长迟缓，而露地栽培则易造成幼苗的死亡。

Death causes and conservation strategies of the annual regenerated seedlings of rare plant, Bretschneidera sinensis

Bretschneidera sinensis Hemsl. is a rare endemic plant in China, and the high death rate of annual seedlings is one of the key endangered causes. Site experimentation was used to discuss the main death causes of seedlings and studied the effects of pH and shading treatments on the growth of seedlings. Results showed that no root hair was presented in the root tip and different seedling stock methods differ significantly in the survival rates. The main death causes of seedlings were decay of root system, drought stress and pest predation, etc. The seedlings were adapt to weak acidic soil (5.0~6.5). Natural shadow under forest middle canopy density or shading net by one layer were helpful to the development of seedlings, whereas too shadowing would delay the growth and opening cultivation would cause the death of seedlings.