南亚热带4个珍优阔叶树种化感作用的生物测定

以萝卜、西南桦为受体植物,以西南桦、红椎、米老排和火力楠为供体植物,从供体植物的纯林内收集鲜叶、未分解和半分解枯落叶以及林下表土制备系列水浸液,通过种子萌发试验揭示其化感作用。结果表明:①西南桦鲜叶以及米老排、红椎和火力楠未分解枯落叶的1∶10水浸液对萝卜种子萌发存在显著的化感作用,其半分解枯落叶和林下表土的系列水浸液大多表现出对萝卜种子萌发的促进作用,但差异不显著;②米老排对西南桦种子萌发的化感作用最为明显,西南桦亦表现出显著的自毒作用,火力楠和红椎对西南桦种子萌发的化感作用相对较弱;③在选择西南桦的混交树种时,红椎是最为理想的伴生树种,其次是火力楠,而米老排则不适合与西南桦混交。

Bioassays of allelopathy for four valuable indigenous broadleaved species in southern subtropical zone

Betula alnoides,Castanopsis hystrix,Mytilaria laosensis and Michelia macclurei are 4 valuable indigenous broadleaved species with large-scale planatation in southern subtropical zone of China.In our experiment,fresh leaves,undecomposed and semi-decomposed litters,and surface layer soils were collected respectively from the 4 species' pure plantations to get aqueous extracts with different concentration,which are then used to test the seed germination of radish and B.alnoides.The results show that ①high-concentration aqueous extracts from fresh leaves of B.alnoides and undiscomposed litters of C.hystrix,M.laosensis and M.macclurei remarkably inhibited seedling growth of radish,while slightly positive effects were found on radish seedling growth for most aqueous extracts of semi-discomposed litters and surface layer soils.②In comparison to M.macclurei and C.hystrix,M.laosensis had the most significant allelopathic effects on seedling growth of B.alnoides,while B.alnoides itself showed strong autointoxication.③ C.hystrix was the most suitable associated species for B.alnoides,and the next was M.macclurei.M.laosensis,however,was not suitable to mix with B.alnoides.