Studies On Diseases And The Effect Of Pathogen On Protective Enzyme Activities Of Pinellia Ternata

Pinellia ternata(Thunb.)Breit.is perennial grass of Araceae. Pinellia ternata is the most commonly used Chinese medicine herb,which has function of ridding of dampness, transforming phlegm,lowering athwart,stopping vomit,removing ruffian and dispeing vinculum,is used in coughing,asthma,excessive phlegmm,nausea,vomit. In recent years,the planting area of Pinellia ternata increases year by year after long-term gathering of wild tuber of Pinellia ternata dried up the wild resoureces and the ecoenvironment worsened.As a result that diseases has become one of serious problem which affect quality and output of Pinellia ternata.Rotten tuber and Phytophthora blight of Pinellia ternata were found as important diseases during the growing season in Tianshui production base. The pathogen was isolated and identified following Koch's Postulates and some fungicides were demonstrated as effective to the pathogen growth and the response of defense enzymes in Pinellia ternata to pathogen were studied in this thesis.The main result are showed in following:1.F.oxysporum was identified as the pathogen causing rotten tube and P.parasitica was identified as the pathogen causing Phytophthora blight of Pinellia ternata according to their morphology,cultural characteristics and pathogenicity. The optimal tempera-ture and pH for mycelial growth of F.oxysporum were 21.9℃and 7.2,respectively.The optimal temperature and pH for mycelial growth of P.parasitica were 27.3℃and 6.8,respectively.2. Some fungicides were screened in lab. experiment and field test indicated that 70% thiophanate-methyl and 58% metalaxyl- mancozeb were effective greatest inhibition of F.oxysporum hyphal elonging.The EC50 were 0.0027,0.0662 g·L-1,respectively;58% metalaxyl-mancozeb and 70% thiophanate-methyl were the most effective in lab. experiment.But the control effect of 58% metalaxyl-mancozeb(500 fold dilution) to the growth of P.parasitica by field tests was higher than that of 70% thiophanate-methyl(500 fold dilution), the efficacy were 97.4%.3.Different leaf types of Pinellia ternata were identified by the methods of natural infection in open field and axtificial inoculation.It was fund that all are infecting disease type.Effect of pathogen on activity of the protective enzyme of peach-leaf types Pinellia ternata leaves showed that:The resut showed that activities of SOD,POD,CAT,PPO and PAL increased greatly after inoculation of F.oxysporum. The activity of SOD inereased by77.1% at 24 h.The maximum activity of POD was 15.9 times than control group and occurred at 72h.The activity of CAT inereased by 52.3% at 48h.The activity of PPO inereased by 98.7% at 96h. The maximum activity of PAL was 3 times than control group and occurred at 48h.The activities of SOD,POD and CAT increased greatly after inoculation of P.parasitica, but there was no obvious change in the activity of PPO.The activity of SOD inereased by 59.9% and 15.1% at 24h and 120 h,respeetively.The maximum activity of POD was 2.98 times than control group and occurred at 72h.The maximum activity of CAT was 3.10 times than control group and occurred at 48h.