【作者】 李莹莹；

【导师】 姜华；

【作者基本信息】 辽宁师范大学 ， 细胞生物学， 2008， 硕士

【摘要】 根癌病是由根癌土壤杆菌(Agrobacterium.tumefaciens)引起的一种世界性的植物病害,大连地区大樱桃的根癌病尤为严重,急需查明该病发病程度,致病原因和病菌株系,从而进行有效的防治、抑制。本文对大连地区的大樱桃根癌病进行了田间调查;从染病的大樱桃植株根系和根际土壤中分离病原菌,进行了形态学、生理生化和分子生物学鉴定;研究了生物农药-壳寡糖对根癌菌的抑菌效果及对染病植株的诱导抗性;探讨了27种中药、内生菌、砧木和化学药剂对根癌菌的抑菌效果及大樱桃根癌病的防制措施。实验结果如下:1、大连地区大樱桃根癌病的发病率为56%、病情指数为29.33%。田间发病调查发现:发病部位在伤口上,伤口是根癌菌侵入的主要通道。湿度大利于接种点癌瘤的形成;癌瘤的形成以22~25℃为宜;碱性、粘重土壤、排水不良的土壤易发病;樱桃癌瘤主要发生在根基部、主根、侧根和支根上;砧木不同,植株对病原菌的抗性不同。2、对从大樱桃感病植株根际土壤和病瘤里分离到的14株细菌,进行了形态学、生理生化和分子生物学三方面的鉴定,认为分离的7号菌株可能是大连地区根癌病的主要致病菌株。3、壳寡糖从800ppm开始对根癌土壤杆菌在实验室中具有抑菌活性,(抑菌活性相当于25ug/mL的青霉素的抑菌强度)。壳寡糖与根癌菌侵染寄主的防御酶活性变化成正相关。壳寡糖处理可提高黄瓜、向日葵感染根癌病植株的防御酶活性,尤其是PAL对壳寡糖处理敏感,在壳寡糖诱导抗性作用中可能是一种关键的防御酶。壳寡糖对根癌病植株有诱导抗病作用。壳寡糖处理后再接菌的黄瓜和向日葵幼苗比直接接菌的显症慢、病情轻,其诱导抗病作用主要表现在病原菌侵入初期,被诱导的植株对病原菌有抗侵入和抗扩展的效果。4进行了大樱桃根癌病防治、抑制研究。27种中药制剂中,大黄和黄连对根癌土壤杆菌具有较强的抑菌性,是很好的植物源生物农药资源。7种不同种类药剂、不同浓度的药效试验比较,抗根癌菌剂K84和抗菌剂402防效较好;针刺接种后再药剂处理,凡接种砧木均长癌瘤;在主根上刮瘤易伤根,且刮瘤后药剂处理无效。6种砧木对根癌病抗性试验中没有筛选出高抗性砧木,但依据发病率、瘤径和植株长势等指标综合评价,马哈利砧木对根癌病有较好的抗性。更多还原

【Abstract】 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.更多还原