濒危树种闽楠种子和幼苗生态学研究(英文)  

Seed and seedling ecology of the endangered Phoebe bournei (Lauraceae)

作　　者：吴大荣[1] 王伯荪[1] 

机构地区：[1]中山大学生命科学学院,广州510275

出　　处：《生态学报》2001年第11期1751-1760,共10页Acta Ecologica Sinica

基　　金：Major Projectof the National Natural Foundation of China(No.3 98993 70 ) and Postdoctral Foundation of Guangdong Province(2 0 0 0 -0 2 2 -4 2 4 442 )

摘　　要：从 1 995至 1 998年 ,通过种子收集器布设、不同程度圈围的样方处理、实验室和野外发芽实验、相邻格子样方调查和土壤中种子的筛选等一系列方法 ,对福建罗卜岩闽楠种质资源保护区内闽楠为优势的常绿阔叶林群落中闽楠种群的果实、种子库、种子散布、果实 /种子捕食、种子萌发和幼苗存活等进行了研究。结果表明 :1 995至 1 996年果实量为 1 1 6个 /m2 ,成熟高峰期在 1 996年 1月中旬。 1 997至 1 998年为 1 0 3个 /m2 ,成熟高峰期在 1 997年 1 2月中旬。 1 997至 1 998年 ,绝大部分 (90 .1 % )的果实直接从母树上掉落 ,低于 9.5 %的果实由鸟类传播。实验室的种子发芽率为 93 % ,而在野外仅为1 2 %。野外发芽率低多由种子霉烂引起。闽楠的种子寿命较短 ,其种子在次年 4月初开始萌发 ,7月之后地面种子即丧失活力。动物捕食不仅影响种子的存活 ,同时也影响幼苗的死亡率 ,未经圈围与圈围的样地中被取食的果实和幼苗数量有显著差异。在新近形成的林窗中或远离母树均降低了果实的迁移和幼苗的死亡率。但各因素交互作用有所不同。密度相关效应发生在 2～ 3个月的幼苗阶段 ,之后 ,密度高低对果实被取食和幼苗死亡没有显著的影响。这些结果表明 ,闽楠种子和幼苗经历较大的环境压力 。To clarify regenerative traits and explore effects of canopy cover, density, distance, dispersers, or predators on fates of seeds or seedlings of Phoebe bournei , fruit fall, seed bank, seed dispersal, fruit/seed predation, seed germination and seedling survival were examined in a mid\|subtropical evergreen broadleaf forest in Luoboyan Nature Reserve, southeastern China. Fruit production averaged 116 fruits/m 2 between 1995 and 1996, and 103 fruits/m 2 between 1997 and 1998. The peak of fruit ripening appeared in mid\|January, 1996, and in mid\|December,1997. Most fruits(90 1%) fell directly from parent trees and less than 9 5 per cent were disseminated by birds between 1997 and 1998. Field and laboratory germination rate differed sharply with 93 0 per cent in laboratory compared to 12 per cent in the field. Poor field germination rate was mainly due to rotted seeds attacked by soil pathogens. Phoebe did not have a persistent seed bank strategy. Its seeds germinated in early April and were inviable after July. Predators affected not only seed survival, but seedling mortality as well. The number of predated fruits or lost seedlings in the unprotected plots differed significantly from that in the protected plots. Recent gaps or far distance from parent trees reduced fruit removal and seedling mortality, but their interaction was not always the case. Density dependence occurred in the very young seedling stage(about 2～3 months),but did not significantly affected fruit predation or mortality of seedlings more than 3 months. These results indicate that Phoebe seeds or seedlings suffer high environmental pressures, i.e., most seeds near parent trees in high moist habitats are susceptible not only to soil pathogens, but to high predation beneath parent trees′canopy as well, which results in poor field seed germination and seedling survival.

关 键 词：闽楠 果落 种子库 种子散布 果实/种子捕食 种子萌发 幼苗存活 濒危树种 

分 类 号：Q948.12[生物学—植物学]