Preliminary Study of Mechanism on the Fermentation of Two Endogenous Actinomycetes Inhibited Cucumber Powdey Mildew

The fermrntation supernatant of endophytic actinomycetes GKSHJA and PR1-8 played a role in cucumber powdery mildew protection.After spraying the fermentation supernatant of endophytic actinomycetes GKSHJA and PR1-8,the impact of the endophytic actinomycetes against Sphaerotheca fuliginea histomorphology were tested by the differential interference,and the enzyme activity of POD,SOD,PAL on cucumber leaf treated by spraying endophytic actinomycetes were tested by the spectrophotometer.The results showed that,inoculated after 48h,the spore germination of water control was 91.1%,while treatment of spraying by the the cell free filtrate of GKSHJA and PR1-8 were only 32.2% and 41.3%.Inoculated after 72h,the maximum colony length of hyphae of water control was 745.1μm,while treatment of spraying by the the cell free filtrate of GKSHJA and PR1-8 were 111.6μm and 134.5μm.After spraying the fermentation supernatant of endophytic actinomycetes GKSHJA and PR1-8,the POD activity in cucumber leaves were increased by 93.23% and 76.73% corresponding the control reduction,the SOD activity were increased by 14.86% and 11.08%corresponding the control,the PAL activity were increased by 60.42% and 35.88%.Tow endophytic actinomycetes inhibited the spore germination,mycelium expansion in histomorphology mechanism,raised the activity of defensive enzymes in cucumber leaf in physiology mechanism.