The Research On Root-cancer Disease Of Cherry In Region Of Dalian

The root-cancer disease is caused by Agrobacterium.tumefaciens,it is a worldwide bacterial disease. In region of Dalian, the cherry trees are infected seriously by this disease , so it was an urgent need to find out the morbidity situation ,the cause of disease, the bacteria strains and seek the effective method to prevent and suppress the disease.This report to the object of cherry trees in region of Dalian, it investigated the morbidity situation and the cause of the disease in orchard, isolated and identified the pathogen by the methods of Morphology, physiology and biochemistry and molecular biology, researched the mechanisms of oligochitosan which induced resistance on infected culture. The results were listed as follows:The result of inwestigating in cherry yard indicated that disease percentage and disease index were 56% and 29.9% respectively.The experiment to the cherry tree in field showed that wounds which were the main spreading channel were the infected position. the humidity was benefit to form the root-cancer. In the temperature between 22-25, The root-cancer was easy to form,The alkaline,thick and poor drainage field was easy to induce the disease.,The root-cancer disease occurred mainly on the base of the root, the main root and lateral root.different root-stocks had different resistance.14 kinds of bacterium strains were isolated and purified from the Rhizosphere soil and knurl.using the methods of Morphology, physiology and biochemistry and molecular biology, the 7th bacterium strain was identified as the pathogen which caused the disease in region of Dalian .Oligochitosan had the resistant effect on Agrobacterium.tumefaciens starting from the concentration of 800mg/L, (the effect was the same to penicillin of 25um/mL). oligochitosan and resistant enzyme had the relation. The resistant enzymes were improved after oligochitosan treatment in cucumber and heliotrope, and PAL was the most obvious, Oligochitosan had the resistence to root-cancer disease, and it may induce a resistant enzyme which acted a key role. After treated by oligochitosan, the disease symptom of the plant appeared later and lighter comparing with the plant that weren't treated. The oligosaccharide had the effect on preventing infection and expanding in the early time.The research on preventing and suppressing was made as following. Rhubarb and Huanglian had better effect on suppressing the Agrobacterium.tumefaciens in 27 kinds of traditional Chinese medicine reagent; The AgrocinK84 and antimicrobial 402 had better prevention effect in 7kinds of reagent. All of the rootstocks appeared knurl after reagent treatment in inoculating plant. Scratching knurl may hurt the root easily. Reagent treatment had no effect to the plant that knurl was scratched. According as 6 rootstocks'sdisease percentage, knurl diameter and the growing situation of plant, mahale rootstock had the best resistance effect in six kinds of rootstocks, although the high resistant rootstock wasn't found.