南亚热带森林几种乔木种子萌发和幼苗生长观察

本文对香椿（Ｔｏｏｎａｓｉｎｅｎｓｉｓ（Ａ．Ｊｕｓｓ．）Ｒｏｅｍ．）、木蝴蝶（Ｏｒｏｘｙｌｕｍｉｎｄｉｃｕｍ（Ｌ．）Ｖｅｎｔ．）、扁斗青冈（ＱｕｅｒｃｕｓｈｕｉＣｈｕｎ）、泡桐（Ｐａｕｌｏｗｎｉａｆｏｒｔｕｎｅｉ（Ｓｅｅｍ．）Ｈｅｍｓｌ）罗浮柿（ＤｉｏｓｐｙｒｏｓｍｏｒｒｉｓｉａｎａＨａｎｃｅ）、枳（ＢｅｒｃｈｅｍｉａｄｕｌｃｉｓＴｈｕｎｂ．）等南亚热带森林乔木种子萌发和幼苗生长进行观察．香椿、扁斗青冈、罗浮柿种子在轻阴（５５％光）条件下萌发率最高，分别为７０％、９０％、３０％，木蝴蝶种子在重阴（３８％光）条件下萌发率最高，为８０％，枳种子在光照条件下萌发率最高，为１５％．阳性树种香椿、木蝴蝶、泡桐、枳幼苗生长速度较快，属速生型树种，其幼苗在光照条件下生长速度最快，森林中树种扁斗青冈、罗浮柿幼苗生长速度较慢，属慢生型树种，其幼苗在轻阴条件下生长较好．随着施肥量的增加，幼苗生长速度明显提高．

SEED GERMINATION AND SEEDLING GROWTH OF SEVERAL TREE SPECIES IN LOWER SUBTROPICAL FOREST

Seeds of Toona sinensis (A. Juss.) Roem., Oroxylum indicum (L.) Vent., Quercushui Chun, Paulownia fortunei (Seem.) Hemsl., Diospyros morrisiana Hance and Berchemiadulcis Thunb. were collected from Guangdong and Guangxi. Seed germination and seedlinggrowth of these tree species were examined under different light and fertilizer conditions.The experiments showed that the germination percentage of seeds of T. sinensis (A. Juss.)Roem., Q. hui Chun and D. morrisiana Hance under light shade (55% of natural light) were74%, 90% and 30%, respectively, and O. indicum Vent. under deep shade (38% naturallight) was 80%. However, the highest germination percentage of B. dulcis Thunb. observedunder natural light condition was 15%. The seedlings of T. sinensis (A. Juss.) Roem., O.indicum Vent., P. fortunei (Seem.) Hemsl. and B. dulcis Thunb. grew fast, especially underlight condition, showing that they are fast-growing trees. The seedlings of Q. hui Chun andD. morrisiana Hance showed slow growth, and they grew better under lightshade. Thebiomass and rate of height in growth of all the seedlings increased markedly with the intreaseofapply in gurea.