Induced Resistance And Pathogenic Mechanism Of The Shrink Disease On Jujube

In recent years, the shrink disease become the most damaging disease of jujube fruit, asthe growing area increase, it has become more and more serious, so the loss of the economicwas imponderable, controlling of the shrink diseases of jujube become the focus ofresearchers, meanwhile, it also become the urgent issues to solve of the productionapplication.The induced disease resistance is regarded as a new way that was studied deeply tocontrol plant disease, more and more researches have been studied at home and abroad. Twovarieties, Qiyuexian is the susceptible variety and Fengmiguan is the resistant variety, havebeen selected as materials in this study.The purpose of this experiment is to select the best inducer and the optimal concentrationwhich control the diseases well. In order to study the mechanism of the induced diseaseresistance, determine the related enzyme activity after induction, the most important purposeis to provide a practical basis for effective control of the control of disease.The research was determined in the jujube plantations by the form of incidence, theresults as follows: the study showed that the inducer of K2MnO4at the concentration of0.05%and0.1%treatment had the best controlling effect, the next treatment were chitosan when thespraying concentration is500mg/L, H202at50mmol/L, chitosan at1000mg/L and2000mg/L,K2MnO4at0.2%and500-flod dilution of pyroligneous acid, The effects of salicylicacid and oxalic acid were poor. First of all,K2MnO4、H2O2and pyroligneous acid have theprotective effects. Although these chemicals have a certain controlling effect on the shrinkdisease, they can bring some damage to jujube fruit.so they wasn’t suitable for spraying in thefield. Finally we thought the most appropriate medication for controlling of disease ischitosan.This thesis proposes disease-resistant cultivar--Fengmiguan and susceptiblevariety--Qiyuexian as test material. The chitosan at500mg/L, salicylic acid at3mmol/L,oxalic acid at1mmol/L were choose as revulsants to spraying in these two cultivars, thesetreatments all can cause enzyme activity increased significantly, for example the protein, PODand CAT were in the higher level than control. Meanwhile, the activity of these enzymescould reach the maximum activities in the third day. The results showed that these physiological indexes had the obvious correlation with the resistance of the jujube. Theenzyme activity of PPO decreased obviously in the first day, and the enzyme activity wassignificantly under than CK in the determination period. The enzyme activity of PAL of thesusceptible cultivars has a certain degree of increase in0-3d. Defense enzymes POD, CAT,PAL, soluble protein played important roles in induced resistance to the shrink disease ofsusceptible cultivars. The mechanism inducing chemoresistance of the different varieties wasnot the same. For fengmiguan, the enzyme activities of CAT POD could be significantlyincreased by the inducer, so same the soluble protein content as them. They could reach topeak in the first day or the fifith day, but the activity of PPO and POD hadn’t change. It’s easyto see that the soluble protein, CAT, POD might play an important part during inducingprocess for fengmiguan.In order to explore the pathogens mechanism of the shrink disease of jujube fruit thatcaused by pathogenic fungi. The cell-wall degrading enzymes (CWDEs) were induced inimproved Marcus’s medium, make the use of the different carbon source as the inducers toinduce the fungi produces different kinds of CWDEs. Results indicated that several kinds ofinducer were effective, as the carbon source was pectin, the fungi of the shrink disease allcould be induced higher content of pectin enzyme. As the carbon was CMC, they couldproduce higher Cx. The enzymes activity that be produced by Fusicoccum aesculi Cordawas higher than the fungi of A. alternate (Fr.) Keissler and Phoma glomerata, When theywere cultivated in the medium that were selected in this experiment. When the pathogenslived in the jujube fruit also could induce certain amount of CWDEs, because of the jujubefruit contains lots of PG and Cx that the pathogens could make use of. So when the pathogensinfected the jujube fruit, the kinds of CWDEs would be induced by pectin and cellulose inhost, which was availed the pathogens to infect the host in the wild.