Effects of organic fertilizer on photosynthesis of the cucumber under autotoxicity stress

Continuous cropping obstacles could seriously decrease cucumber(Cucumis sativus L.) yield and quality.Autotoxicity was one of the most important factors of cucumber continuous cropping obstacles.Up to date,reports about the mechanism of organic fertilizer increasing the ability of resistance to autotoxicity were limited.In this paper,sand culture experiment was carried out to study the effect of cinnamic acid(CA),p-hydroxybenzoic acid(HA) stress on photosynthesis of cucumber seedlings.The results showed that chloroplast ultrastructure of cucumber suffering from CA or HA stress was distinguished by membrane melting and decreasing grana lamellae.CA or HA stress led to the decline in the contents of chlorophyll and carotenoid,the rate of photosynthesis.On the other hand,the content of H2O2 was increased by CA or HA stress.Adding organic fertilizer could significantly decrease H2O2 content,whereas increase the contents of chlorophyll and carotenoid,the rate of photosynthesis as well as cucumber growth under HA or CA stress.