樱桃砧木实生苗对根癌菌侵染的抗性及生理响应

摘要

以贵州樱桃的6个砧木实生苗为材料,采用人工接种根癌菌的方法,探讨它们对根癌菌侵染的抗性及生理响应特征,评价其抗病性能力.结果显示:(1)接种根癌菌120 d后,青岩樱桃实生苗发病率较低(6.67％),冠瘿瘤直径较小( 1.76 mm),感病系数也较低(6.67),属高抗砧木；沿河樱桃实生苗发病率高达50.0％,冠瘿瘤直径达6.43 mm,感病系数达33.76,属高感砧木.(2)感染根癌菌后,各樱桃砧木幼苗的生理特性受到一定影响,其叶片游离脯氨酸含量增加,根系过氧化物酶(POD)和超氧化物歧化酶(SOD)活性增强,而过氧化氢酶(CAT)活性降低,其中,青岩樱桃的游离脯氨酸含量升高幅度最大,沿河樱桃的保护酶活性变化幅度明显较大.(3)樱桃砧木幼苗的发病率与感病系数呈显著正相关(0.98*)；发病率与SOD活性、感病系数与POD活性和SOD活性均呈显著正相关,相关系数分别为0.86、0.82、0.83;其余指标间相关性不显著.研究表明,6个樱桃砧木实生苗对根癌菌的抗性有明显差异,并以青岩樱桃最强,且其抗性强弱与其感病后叶片脯氨酸含量和根系的POD、SOD活性增加幅度有密切关系.%The tolerance and physiological response to crown gall of six types of cherry rootstocks seedings in Guizhou Province were investigated using inoculating experiment. The results showed that:(l)The disease incidence of Qingyan cherry seeding was only 6. 67% , and its average tumor diameter and tolerance ratio were 1. 76 mm and 6. 67, respectively, demonstrating the highest tolerance to this disease. However, Yanhe cherry demonstrated the lowest tolerance with 50. 0% of disease incidence,6. 43 mm of tumor diameter, as well as 33. 76 of tolerance ratio. (2) Obvious physiological responses were obtained after the incidence of this disease. The content of free proline in leaf considerably increased,as well as the activities of peroxidase (POD) and superoxide dismutase (SOD) were enhanced. Conversely the catalase (CAT) activity went down. Free proline content of the Qingyan cherry increased amplitude, and protective enzymes of Yanhe cherry were significantly changed. (3)The disease incidence was closely correlated with the tolerance ratio and SOD activity,with correlation coefficient was 0. 98 and 0. 86 respectively. Also the tolerance ratio was closely correlated with the activities of POD (r=0. 82* ) and SOD (r = 0. 83* ). Obviously the tolerance to crown gall of six types of cherry rootstocks seedings was significant different, and Qingyan cherry demonstrated the highest tolerance. The resistance was closely related with the content of free proline , as well as the increase of POD and SOD activities.