化感物质抑制连作黄瓜生长的作用机理

Mechanism of Allelochemicals Inhibiting Continuous Cropping Cucumber Growth

苯丙烯酸、对羟基苯甲酸为黄瓜根系分泌物中的主要化感物质组分。通过模拟根系分泌物中的化感物质进行土培和水培试验,证明苯丙烯酸、对羟基苯甲酸对连作黄瓜根系生长有明显的抑制作用。在50～250μmol/L浓度范围内,随处理浓度的加大,抑制根系对K+、NO3、H2PO4吸收的作用显著,养分外渗速率加快,组织外渗相对电导率逐渐提高。苯丙烯酸、对羟基苯甲酸强烈地抑制黄瓜根系脱氢酶、根系结合ATP酶、硝酸还原酶、超氧化物歧化酶的活性,随理浓度的增大抑制作用增强。

Cinnamic acid and p-hydrobenzoic acid are main components of the allelochemicals in cucumber root exudates. Soil culture and water culture experiments carried through imitating the allelochemicals of the root exudates showed that cinnamic acid and p-hydroxybenzoic acid obviously inhibited continuous cropping cucumber growth. When the concentration of the allelochemicals was between 50 and 250μumol/L, the inhibition of cucumber roots from imbibing K+,NO3 and H2PO4 increased as the concentration increased, and so did the rate of nutrient leakage and the relative electric conductivity. Also cinnamic acid and p-hydroxybenzoic acid strongly inhibited the activities of root dehydrogenase, root-combined ATPase,NR and SOD. The higher the concentration,the stronger the inhibition. It was also found that cinnamic acid raised POD activity.