橡胶叶水浸提液对3种蔬菜作物的化感潜力

采用培养皿滤纸法测定不同浓度橡胶叶水浸提液对番茄、生菜和萝卜3种蔬菜作物的化感潜力,以进一步理解橡胶树的化感作用.结果表明,在低浓度(≤50 g/L)下,橡胶叶水浸提液对3种作物的种子发芽势、发芽率、发芽指数、、活力指数表现为促进作用或者较弱的抑制作用.随着浓度的增加,促进作用开始减弱,而抑制作用不断增强.特别是在高浓度(200 g/L)下,橡胶叶水浸提液对3种蔬菜作物种子发芽势、发芽率、发芽指数、活力指数表现出强烈的抑制作用;随着水浸提液浓度的增加,番茄、生菜种子的平均发芽时间不断延长,而萝卜种子的平均发芽时间先是缩短,而后延长;随着浓度的增加,橡胶叶水浸提液对番茄、生菜、萝卜幼苗根长的抑制作用不断增强;当橡胶叶水浸提液为0～100 g/L时,对番茄、生菜、萝卜幼苗苗高的促进作用逐渐增强,但在200 g/L时,对番茄、生菜的促进作用明显减弱,而对萝卜幼苗苗高表现为抑制作用.当橡胶叶水浸提液为200 g/L时,番茄、生菜、萝卜的综合化感效应指数分别为-0.125、0.081、-0.304,据此推断,3种蔬菜作物对橡胶叶水浸提液的化感敏感性大小依次为萝卜＞番茄＞生菜.

Potential allelopathy of aqueous extracts from rubber leaves on three vegetables

In order to better understand the allelopathy of rubber tree, potential allelopathy of aqueous extractsfrom rubber tree(Hevea brasiliensis) leaves under different concentrations on tomato (Solanum lycopersicum L.), lettuce(Lactuca sativa L.) and radish (Raphanus sativus L.) was examined through a petri dish assay with imbibed seeds. Theresults showed that aqueous extracts of rubber leaves at lower concentrations (50 g/L) exhibited stimulatory or evenweak inhibitory effects on the germination potential, final germination percentage, germination index, vigor index ofthree vegetable seeds. With the concentration increasing, the positive effect tended to be weakened, while, inhibitioneffect continuously enhanced. In particular, aqueous extracts of rubber leaves at high concentration of 200 g/L showedstrong allelopathic inhibitory effect on the germination potential, final germination percentage, germination index, vigorindex of three vegetable seeds. With the increases of concentration of aqueous extracts from rubber leaves, meangermination time of tomato and lettuce seeds continuously prolonged, whereas mean germination time of radish seedsshortened firstly, and then prolonged. With the increases of concentration, aqueous extracts from rubber leaves hadincreasing inhibitory effects on root length of tomato, lettuce and radish seedlings. Aqueous extracts of rubber leaves atconcentration of 0~100 g/L had increasing stimulative effects on shoot height of tomato, lettuce and radish seedlings,but at concentration of 200 g/L, the promoting effects on shoot height of tomato, lettuce seedlings significantlyweakened, whereas the inhibitory effects on shoot height of radish seedlings were found. At concentration of 200 g/L ofaqueous extracts, comprehensive allelopathic indices of tomato, lettuce and radish were -0.125, 0.081 and -0.304,respectivel y. It was concluded that the allelopathicsensitivity of three vegetables to aqueous extracts fromrubberleaveswasintheorderofradish>tomato>lettuce.