薄荷化感物质的作用及其初步分离

以小麦(Triticum aestivum)、青菜(Brassica chinensis)和萝卜(Raphanus sativus)3种作物为受体，对薄荷(Mentha Haplocalyx)化感物质的作用进行了研究．结果表明：薄荷根分泌物显著促进小麦幼苗和幼根的生长，显著抑制青菜幼苗和幼根生长，显著促进萝卜幼苗而抑制其幼根生长．薄荷地上部分水浸液显著抑制青菜、萝卜的种子萌发和幼苗、幼根的生长；萝卜比青菜更敏感，幼根比幼苗更敏感；随着化感物质浓度的降低，抑制作用逐渐减弱、消失，甚至转变为促进作用．水浸液经氯仿、石油醚萃取后，剩余水相浓度变小、水势升高，但其抑制作用反而更加强烈．这说明，这种极其强烈的抑制作用不是低水势而是化感物质造成的；而且，剩余水相的抑制作用被同样具有抑制作用的石油醚相和氯仿相组分所削弱。即化感组分之间存在拮抗作用．剩余水相经大孔树脂进一步分离得到的3个组分都极显著地促进青菜幼苗的生长．这表明，水相强烈的抑制作用是由起极显著促进作用的3个组分的混合物产生的，且排除了水势降低的影响．但组分2显著抑制青菜、萝卜种子的萌发和幼根的生长．图2表4参26

EFFECTS OF MINT ALLELOCHEMICALS AND ITS PRELIMINARY ISOLATION

The effects of mint ( Mentha haplocalyx ) allelochemicals were studied on three crops: wheat ( Triticum aestivum ),Chinese cabbage ( Brassica chinensis ) and radish ( Raphanus sativus ).The exudates of mint root showed obvious effects on seedling and root growth of the three crops: stimulating the growth of wheat,inhibiting that of Chinese cabbage,and stimulating the growth of seedling but inhibiting that of root of radish. The aqueous extract from aerial part of mint significantly inhibited both the germination of seed and growth of seedling and root of Chinese cabbage and radish. Radish was more sensitive to the allelopathic effect than Chinese cabbage,and the root more sensitive than seedling. The suppression gradually decreased,disappeared and even changed into stimulative effect when the concentration of extract declined. By successively extracting with chloroform and petroleum ether,the aqueous extract was separated into three parts (phases). The inhibitory effect of the remaining aqueous phase significantly increased. Since the concentration decreased and water potential increased in the remaining aqueous phase,it was revealed that the extremely strong inhibitory effect was caused by the allelochemicals rather than the low water potential. It was also revealed that the inhibitory effect of the aqueous phase was weakened by the components in the phases of chloroform and petroleum aether,which had the same inhibitory effect,i.e.,there was an antagonism present between the components in the separated phases. With the amberlyst,the aqueous phase was further separated into three components all of which significantly stimulated the seedling growth of Chinese cabbage. It was shown that the extremely strong inhibition of aqueous phase was caused by the mixture of the three components with strongly stimulating effect,excluding the decreasing effect of water potential. However,component II obviously inhabited the seed germination and root growth of Chinese cabbage and radish. Fig 2,Tab 4,Ref 26