滇杨枯落叶和林下土壤的化感潜力1）

采用生物测定法，对滇杨枯落叶和林下土壤的化感潜力进行了研究。结果表明：滇杨枯落叶浸出液会延缓三叶鬼针草种子萌发，抑制胚芽生长，在2．5％的处理质量分数下，对胚根的生长具有抑制作用，化感效应敏感指数RI＝－0．22。对株高和生物量的抑制作用，随着浇灌枯落叶浸出液质量分数及添加枯落叶粉比例的增加而增强，质量分数为2．5％时，株高的RI＝－0．17，生物量的RI＝－0．54。在添加80％枯落叶粉的处理下，株高的RI＝－0．54，生物量的RI＝－0．67，生物量的化感效应敏感程度高于株高。滇杨林下土壤对三叶鬼针草生长无化感抑制作用，均表现为化感促进作用，＞2～10 cm深的土壤促进作用最强，株高和生物量的化感效应敏感指数分别为0．57、0．73。

Allelopathic Potential of Leaf Litter and Forest Soil of Populus yunnanensis Dobe

We studied allelopathic potential of leaf litter and forest soil of Populus yunnanensis Dobe by bioassay.The leaf litter extract of P.yunnanesn is Dobe could delay the seeds germination and inhibit plumule growth of Bidenspi losa L., radicle growth was inhibited when at concentration of 2.5%, and the allelopathic effect sensitivity index ( RI ) was -0.22.Inhibi-tion effects on plant height and biomass were increased with the increasing concentration of extract leaf litter and adding proportion of leaf litter powder, the RI for plant height and biomass were-0.17 and-0.54, respectively, when the concen-tration was at 2.5%, moreover, and adding leaf litter powder proportion of 80%the RI about plant height and biomass were-0.54 and -0.67, respectively.The allelopathic sensitivity degree of biomass was higher than plant height.The forest soil had the promotion effect on the growth of Bidens pilosa L..The soil in >2-10 cm deep had strong stimulated effect, and the RI of plant height and biomass were 0.57 and 0.73, respectively.