| Cucumber has2000years of cultivation history in China, originated in the tropical forests of southregion in Himalayas, it is1a sprawling plant of Cucurbitaceae cucumis. Because of natural conditions andthe varieties of vegetables, cucumber in the whole growth period are vulnerable to diseases and stress ininsect pests. S.fuliginea and Aphis Gossypii is a kind of typical diseases and insect pests in its growthprocess. Which product the high quality and high yield of green cucumber become obstacles. From thecurrent study found that there is no report on physiological and biochemical mechanism of cucumberwhich endanger by S.fuliginea and Aphis Gossypii. In view of this, this paper choose the seedling growthof cucumber, studied a series of adaptive response which stressed in S.fuliginea and Aphis Gossypii fromthe physiology, in order to reduce the infection of plant diseases and insect pests of cucumber to suffer andproduction of high quality and high yield of cucumber to provide certain theoretical basis.By artifical inoculation method,studied the the Physiological and biochemical indexes Changes ofCucumber after being infected by S. fuliginea,the result showed that the respiration intensity of cucumberleaf showed a trend of increase, and the photosynthetic rate is restrained, it presents a weakening trend,because the chlorophyll content and photosynthesis has certain correlation, so also was, MDA contentshowed increasing trend, the soluble sugar change is relatively complex which its content may is relatedwith many factors, definite descriptions of its change trend, the content of soluble protein increasedobviously, because of its play a key role in resisting adversity stress. the free proline decreased obviouslycontent, POD, SOD activity showed the trend of increased, and CAT activity showed a reduced increasedfirst, then decrease trend.The contents of leaf chlorophyll，MDA，soluble sugar，soluble protein and free proline were detectedafter treated by different Aphis Gossypii populations in cucumber，also the activities of POD，SOD andCAT.The results show that after the Aphis Gossypii feeding，chlorophyll，soluble protein and prolinecontents decreased，indicating that the resulting mineral malnutrition，leading to inhibition of chlorophyll，protein and proline synthesis. The more Aphis Gossypii，the more increased MDA content，whereasinhibition of MDA production. When160aphids/plant reached，MDA was highest，the reason was that thehigh density Aphis Gossypii reduce the stability of the stability of the membrane system. It damaged themaximum degree of membrane，and enhanced accumulation of MDA in leaves of cucumber，which greatlypromoted the cucumber leaf senescence and reduced the cold hardiness of cucumber leaves. As the aphidsfeeding on plant sap，most sap were discharged by the form of honeydew，sometimes up to90%，so aphidhoneydew excretion and the excretion of frequency can be used as the feeding rate and digestive capacityof signs. Most honeydew were sugars and amino acids，which could be used to supply nutrition，so as toimprove the soluble sugar content of cucumber leaves. After a small amount of aphids fed plant sap，itcould reduce the SOD，POD and CAT activities，but a certain number of aphids could enhance the SOD，POD and CAT activities.By measuring the influence of the Physiological and biochemical indexes when duressed the different densities Aphis Gossypii after infected by S.fuliginea.The result showed that with the increase of the AphisGossypii density after infected by S.fulegenea, the content of chlorophyll gradually reduced. While MDAcontent shows that the more Aphis Gossypii,the MDA content is higher, when decrease the numbers ofAphis Gossypii, the MDA content rather than controls. Soluble sugar content shows that the more AphisGossypii which damaged after infection with,the sugar content is higher, it showed that after cucumberinfected by S.fuliginea,a certain number of Aphis Gossypii could improve the cucumber leaf soluble sugarcontent. After infected by,when Aphis Gossypii in feeding, it can reduce the cucumber leaf soluble proteinand free proline content. With the increase of the Aphis Gossypii density after infected by S.fuliginea,theSOD, POD, CAT activity also gradually rise.Studied the influence of cucumber leaf chlorophyll content, MDA content, soluble sugar content,soluble protein content, free proline content, POD activity, SOD activity and CAT activity which infectedby S.fuliginea and Aphis Gossypii in different time. Results show that chlorophyll content，free proline andsoluble protein content which diseased first and later infected by Aphis Gossypii processing is higher thanthe other two processing, MDA content, soluble sugar content which infected by Aphis Gossypii first andlater diseased is higher than the other two processing, SOD activity, CAT activity which infected by AphisGossypii first and later diseased is higher than the other two processing, while the POD activity differencebetween individual processing was not significant (p <0.05).Study the mixture of insecticides and fungicides to influence the cucumber leaf chlorophyll content,MDA content, soluble sugar content, soluble protein content, free proline content, POD activity, SODactivity and CAT activity which infected by S.fuliginea and Aphis Gossypii. Results show that after thestress of diseases and pests, spraying a certain concentration of Azoxystrobin and imidacloprid couldimprove cucumber leaf chlorophyll content, free proline content and soluble protein content, whileimidacloprid and Azoxystrobin can reduce the cucumber leaf MDA content, Spraying a certainconcentration of imidacloprid have great influence to soluble sugar content which the Azoxystrobin to theimpact is not big, the cucumber under adversity stress, the body of the three kinds of enzyme activity showelevated state, when hit by a certain concentration of the drug after the adjustment, the SOD activityincreased, probably because of pesticide effect is greater than the pesticide effect for the prevention andcontrol of plant diseases and insect pests. The POD and CAT activities of under the regulation ofimidacloprid, the reason was above; its activities falling under the adjustment of Azoxystrobin, may be dueto the effect of pesticides because of less than pesticide effect for the prevention and control of plantdiseases and insect pests. |
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