Study On Physiological And Biochemical Mechanisms Of The Downy Mildew Resistance Increased From Cucumber Accompany With Wheat

As the important vegetable plant, cucumber (Cucumis sativus L.) has great growth area in under-glass culture, the agriculture development was influenced by continuous cropping obstacle what was caused by continuous cropping. Downy mildew is one of the most important diseases in cucumber production, it can also result in no yield because of the quick onset after pathogen infection. Wheat (Triticum aeslivum L.) is worldwide gramineous crop with allelopathy, some study indicated that accompany with wheat has a positive impact on cucumber downy mildew, but the exact cause is not clear, and need be studied in further.This study investigate the affect of disease-related protein about resistance downy mildew、 cytoarchitectonics、protective enzyme and HRGP in cucumber leaves after accompany with wheat, and purpose of this study is identified the physiological and biochemical mechanisms that accompany with wheat can raise the resistance of cucumber, to provide a theory for production practice. The main results of this experiment show as follows:1. Accompany with wheat increases the cucumber yield, the yield increase6.41%, and control the downy mildew happen of cucumber.2. Accompany with wheat influence the photosynthesis and osmoregulation index of cucumber leaves. Accompany with wheat raise the CO2concentration in cells, cut down the content of chlorophyll a、chlorophyll b and total chlorophyll in cucumber, increase the photosynthetic rates、stomatal conductance and transpiration rates in plant growth midanaphase; accompany with wheat raise the soluble sugar content, increase the content of free praline and soluble protein in cucumber growth metaphase, degrade the relative conductance in cucumber growth midanaphase.3. Accompany with wheat influence the protective enzymes activities and MDA content of cucumber leaves. Accompany with wheat cut down the activitie of SOD, increase the activitie of PAL, depress the activities of POD、CAT and PPO in cucumber growth anaphase; accompany with wheat cut down the MDA content in cucumber growth prophase and anaphase.5. Accompany with wheat influence the MDA content of cucumber leaves. In protophase of plant growth, accompany with wheat depress the MDA content; in metaphase of plant growth, accompany with wheat increase the MDA content; in anaphase of plant growth, accompany with wheat degrade the MDA content.4. Accompany with wheat influence the stomata character of cucumber leaves. In protophase of plant growth, accompany with wheat depress the stomatal opening rate and stomatal size; in metaphase of plant growth, accompany with wheat cut down the stomatal density、stomatal opening rate、stomatal size and stomatal area percentage; in anaphase of plant growth, accompany with wheat degrade stomatal density、stomatal size and stomatal opening rate.5. Accompany with wheat influence the content of lignin and HRGP in cucumber leaves. Accompany with wheat increase the lignin content in cucumber growth prophase and metaphase; accompany with wheat raise the HRGP content in cucumber growth metaphase.6. Accompany with wheat influence the protein in cucumber leaves, there has seldom different protein point. In protophase of plant growth, the accompany with wheat has more different point; in metaphase of plant growth, the monoculture has more discrepancy point; in anaphase of plant growth, both accompany and monoculture has a trifle of discrepancy protein point.Form the above, the photosynthesis index and the protective enzymes activities increase, the stomatal opening rate、stomatal size and stomatal area percentage change, these implement the physiological and biochemical mechanisms of the downy mildew resistance increased from cucumber accompany with wheat.