不同年龄香果树种子雨和种子库及其更新特征

对宝天曼自然保护区香果树种子雨、土壤种子库进行了观测,并进行不同微生境播种实验,研究其种子萌发及幼苗生长动态。结果表明:(1)不同龄级香果树种子雨持续时间及其高峰期有所不同,种子雨强度存在极显著差异。(2)20~50龄级香果树的种子饱满率、土壤种子库中种子密度均显著低于其他龄级,但其不同类型种子的水平和垂直分布规律一致;大约80%的香果树种子在其萌发前消失,剩余种子中以霉烂种子密度最高(9.81粒·m-2),饱满种子密度最低(1.94粒·m-2)。(3)野外育苗实验表明,不同龄级香果树所产饱满种子的萌发率及幼苗存活率差异不显著,其种子萌发率约为16.93%,但仅有3.86%的幼苗寿命超过5个月;不同微生境对香果树幼苗存活率产生显著影响,林窗是其最适宜微生境。研究认为,人工采集香果树种子,于次年4月份在原生境下播种;清理母树冠下和冠缘的地被物,增加林缘空地地被物覆盖度,以减少香果树种子的损失,改善香果树种子萌发和幼苗生长的光照条件,以利于幼苗根系的生长,促进香果树的自然更新。

Seed Rain, Seed Bank and Natural Regeneration of Emmenopterys henryi in Different Age Classes

Emmenopterys henryi seed rain and soil seed bank in Baotianman Nature Reserve were observed. Seeding experiments at different microhabitats were conducted, and the dynamics of seed germination and seedling growth were investigated. The results showed that: (1) there are differences in time duration and peak period of E. henryi seed rain at different age classes. Obvious differences in seed rain intensity were also observed. (2) E. henryi seeds of 20-50 age class exhibit an obviously lower satiation rate than that of other age classes. The seed density of the E. henryi seed bank is obviously lower than that of other age classes. However, different types of seeds exhibit uniform horizontal and vertical distribution rules. Approximately 80% of E. henryi seeds disappear before germination. Rotten seeds exhibit the highest density (9.81 particles·m^-2), whereas fully grown seeds exhibit the lowest density (1.94 particles·m^-2). (3) Outdoor experiment of growing seedlings shows no obvious differences in germination and seedling survival rates of fully grown seeds at different age classes. E. henryi germination rate is approximately 16.93%. However, only approximately 3.86% of seedlings exhibit more than five months of life. Different microhabitats show a clear influence on the survival rate. Forest gap is the most suitable microhabitat. This study demonstrates gathering and seeding of E. henryi seeds artificially at the original habitat in the next April, cleaning ground covers under female crown and edge, increasing coverage of edge space to reduce loss, and improving light conditions for germination and growth to benefit the growth of the seedlings root system and promote its natural regeneration.