单性木兰种子雨与天然更新的初步调查

Seed rain and natural regeneration of Kmeria septentrionalis in Mulun of Guangxi

以位于广西木论国家级自然保护区内的单性木兰为对象,调查了其种子的天然散播和天然萌发、幼苗幼树的生长情况及鼠类对种子的取食危害情况。结果表明:单性木兰种子具休眠特性,种子到达地面后并不立即萌发,至次年4月初—4月中旬才见子叶出土;鼠类对单性木兰种子的取食具有长期性,从种子散播初期至种子萌发的这段时间鼠类均对其种子进行取食(包括地表和土壤中的种子);利用铁丝网罩进行种子萌发的对比实验发现,即使是在无鼠类危害的情况下,单性木兰的种子萌发率也很低;单性木兰天然更新过程中由种子转化成幼苗这个阶段还存在着严重的障碍,低的种子萌发率难以满足单性木兰种群的正常更新。

With the Kmeria septentrionalis in Mulun National Nature Reserve of Guangxi as test object, its seed rain and natural germination, growth status of seedlings and young trees, and seed predation by rodents were investigated. The results showed that K. septentrionalis seeds had dormancy character, i. e. , didn＇ t germinate immediately after falling onto the ground until the beginning to the middle ten days of next April. The predation of rodents on seeds （ including those on the ground and in the soil） lasted long term, from the initial stage of seed falling to germination. The and no rodent germination rate of perfect seeds was low, even under the protection of enclosure damage. There was a serious obstacle in the natural generation of K. during the development stage from seed to seedling. The low seed germination rate could not satisfy the normal generation of K. septentrionalis.