模拟林窗光照条件对南亚热带雨林土壤种子库幼苗萌发的影响

2002～2003年研究了模拟林窗光照条件对福建南靖和溪南亚热带雨林土壤种子库幼苗萌发的影响.结果显示:和溪南亚热带雨林土壤种子库萌发的乔灌木及木质藤本幼苗的种类有43种,其优势成分香楠(Randia canthioides)、三叉苦(Euodia lepta)、山油麻(Trema dielsiana)、山黄麻(Trema orientalis)、楤木(Aralia chinensis)等为先锋物种,杜茎山(Maesa japonica)为林下植物,榕属植物(Ficus)生态位较独特.在数量上,春季最高(1 391株/m2),秋季次之(1 116株/m2),夏季(940株/m2)和冬季(930株/m2)最低;在垂直分布上,土壤种子库0～2 cm与2～5 cm两个层次在种类组成上是一致的,对于同个物种一般上层数量明显高于下层;在出苗顺序上,各物种在不同季节的出苗顺序基本一致,白楸(Mallotuspaniculatus)、三叉苦、山黄麻、盐肤木(Rhus chinensis)、山乌桕(Sapium discolor)、楤木等植物一般在萌发实验开始的早期出苗,香楠、笔管榕(Ficus virens)、凸脉榕(Ficus nervosa)、山油麻、黄毛榕(Ficus fulva)、玉叶金花(Psychotriapubescens)、野牡丹(Melastoma candidum)等在中期和晚期出苗,杜茎山、拟赤杨(Alniphyllum fortunei)、雅榕(Ficus concinna)、红栲(Castanopsis hystrix)等一般在萌发实验晚期出苗.

Effect of Simulating Forest Gap's Illumination on Germination of Seed from Seed Bank in Subtropical Rainforest in Hexi, Nanjing, China

The effect of simulating forest gap's illumination intensity(10% of full sunlight) on germination of soil seed bank of subtropical rain forest in Hexi Nanjing,China was studied.Results showed:there were 43 of tree,shrub and vine species seedlings in our germinating experiment of Hexi south subtropical rain forest's soil seed bank.The common species were Euodia lepta,Randia canthioides,Maesa japonica,Trema orientalis and species of ficus,which were all pioneer species.The seedlings of spring sample,reached 1 391 indiv./m~2 was the highest,then that of autumn sample was 1 116 indiv./m~2,that of summer sample was 940 indiv./m~2 and that of winter sample was 930 indiv./m~2.Seedlings that germinated from upper layer of soil seed bank(0~2 cm) was more than that of under layer soil seed bank(2~5cm),although composing species being similar.Species had different germinating sequence in soil seed bank after forest gap forming.In our experiment,seeds of Mallotus paniculatus,Euodia lepta,Trema orientalis,Rhus chinensis,Sapium discolor and Aralia chinensis germinated in the forepart,Randia canthioides,Trema dielsiana,Ficus fulva,Psychotria pubescens and Melastoma candidum,germinated in the middle phase and late phase,Maesa japonica,Ficus concinna,Castanopsis hystrix and Alniphyllum fortunei,germinated in the late phase.