【作者】 朱圣杰；

【导师】 丁克坚；

【作者基本信息】 安徽农业大学 ， 植物病理学， 2004， 硕士

【摘要】 本文研究了6个青枯菌菌株的致病性、生化变种、胞外酶的变化，5个番茄品种（系）对青枯病的苗期和成株期抗病性鉴定，同时研究了接种后番茄根部和叶片发生的生理生化变化，以初步探讨番茄抗青枯病的生理生化机制。所得结果概括如下：经测定，供试6个青枯菌菌株均具有致病性，且致病性由强到弱依次为HF、HX、YS、FY、HN2、HN1。生化变种的测定结果表明，仅FY菌株不能利用甜醇，属生化变种Ⅲ的一个亚型，即Ⅲ-1，而其余5个菌株均属生化变种Ⅲ。胞外酶活性的测定结果表明，随培养时间的延长，果胶酶和纤维素酶两种酶活性都逐渐升高，培养7～9天酶活性均达最大值，但果胶酶活性最大值与菌株致病性之间相关性不大（r=0.6371），而各菌株纤维素酶活性最大值与致病性高度正相关（r=0.9526）。番茄苗期采用伤根灌注法接种，分别于接种后1周、2周、3周进行发病株率调查。3次调查结果一致，5个品种（系）苗期均为感病品种（系），但品种（系）间发病株率存在显著差异，强丰最高，新星最低，其余品种（系）介于两者之间。番茄成株期采用伤根灌注法接种鉴定，结果表明，新星、夏钻石、黄山1号3个品种（系）为抗病品种（系），抗性指数分别为12.9、12.3、10.9，黄山2号抗性指数为8.9，属中抗品种（系），而强丰抗性指数为2.5，属感病品种（系）。番茄苗期未接种处理各品种（系）叶片5种防御酶活性处在动态平衡中，接种后，各品种（系）叶片POD、PPO、PAL3种酶活性均升高，新星、夏钻石、黄山1号、黄山2号始终高于对照，且上升速度、最大增幅、峰值均高于强丰，而强丰接种后初期高于对照，后期则低于对照。接种后，各品种（系）叶片SOD和CAT活性变化紊乱，没有规律。所以，接种青枯菌后番茄叶片POD、PPO、PAL3种酶可以作为早期筛选抗病品种（系）的辅助指标，而SOD和CAT2种酶还有待于进一步研究。番茄成株期未接种处理各品种（系）根部和叶片5种防御酶（POD、PPO、PAL、SOD、CAT）酶活性处在动态平衡之中，均在一定范围内波动，但幅度不大，抗病品种（系）和中抗品种（系）POD和PAL活性始终高于感病品种（系）。接种后，无论是根部还是叶片，各品种（系）POD、PPO、PAL、SOD4种酶活性均升高，其中PAL和SOD表现较为敏感，活性高峰出现早，而且PAL出现两个活性高峰，其余3种酶只有一个活性高峰。各品种（系）根部POD、PPO、PAL酶活性的峰值和最大增幅均高于叶片，SOD恰好相反。总体上，无论是根部还是叶片，接种后抗病品种（系）和中抗品种（系）4种酶活性均高于对照，且酶活性上升速度和峰值均高于感病品种（系）；而感病品种（系）前期高于对照，后期则低于对照。各品种（系）4种酶活性峰值的高低与品种（系）抗病性均呈正相关。接种后，各品种（系）根部CAT活性均先降低后升高，第6天达到高峰，且峰值和最大增幅与品种（系）抗病性呈正相关。抗病品种（系）叶片CAT活性变化与根部相同，中抗品种（系）接种后2天内基本没有变化，此后升高，并始终高于对照，第6天达到高峰；感病品种（系）接种后CAT活性缓慢升高，第6天达到高峰，此后下降，第8天后一直低于对照。番茄成株期接种青枯菌后体内POD、PPO、PAL、SOD 4种酶可以作为番茄抗青枯病的生理生化指标，而CAT还有待于进一步研究。番茄成株期未接种处理，无论是根部还是叶片，木质素含量与品种（系）抗病性梯度一致。接种后，无论是根部还是叶片，木质素含量均升高，抗病品种（系）始终高于中抗品种（系），后者又高于感病品种（系），而且木质素含量上升速度和最大增幅与品种（系）抗病性梯度一致。番茄成株期接种青枯菌后，无论是根部<WP=7>还是叶片，各品种（系）总酚含量均升高，抗病品种（系）和中抗品种（系）第2天和第6天出现两个高峰，且第一个峰值高于第二个，而感病品种（系）第4天达到高峰，峰值显著低于其余品种（系），这与PAL活性变化规律基本一致。接种后，各品种（系）总酚含量均始终高于对照，且峰值高低与品种（系）抗性梯度一致。番茄成株期接种青枯菌后体内木质素含量和总酚含量可以作为番茄抗青枯病的生理生化指标。番茄成株期接种青枯菌后，抗病品种（系）和中抗品种（系）根部和叶片POD同工酶谱带数没有变化，PPO同工酶多了1条新酶带，而感病品种（系）根部和叶片POD同工酶多了1条新酶带，PPO同工酶多了2条新酶带。接种后，抗病品种（系）和感病品种（系）的根部和叶片SOD同工酶多了2条新酶带，而中抗品种（系）根部多了3条新酶带，叶片多了2条新酶带。更多还原

【Abstract】 In this paper, the pathogenicity, biovar, extracellular enzyme of six strains and the seedling and adult resistance identification of five tomato cultivars to bacterial wilt were studied. Meantime, the physiological and biochemical changes were studied after inoculation with Ralstonia solanacearum in order to clarify the physiological and biochemical resistance mechanism of tomato to bacterial wilt. The results were as following:The results indicated, the six tested strains all had pathogenicity and the pathogenicity order from strong to weak was HF,HX,YS,FY,HN2,HN1.The FY strain couldn’t utilize eulcital and belonged to a subtype of biovar Ⅲ —Ⅲ–1,while others strains belonged to biovar Ⅲ. The results of extracellular enzyme activities indicated, the extracellular enzyme(PG and EG) activities increased accompanied with the prolongation of cultivation time gradually, and the enzyme activities reached the max in 7～9 days after cultivation. The relativity between the max of PG activity and pathogenicity was not too large（r=0.6371），while the relativity between the max of EG activity and pathogenicity was very large （r=0.9526）.Tomato cultivars were inoculated with R.solanacearum with the pouring method of the seedling’s hurt root and the diseased plant rate was investigated at the first, second, third week respectively after inoculation. Three times investigation results were coincident. Five tomato cultivars were all susceptible in seedling, but there were significant difference on the diseased plant rate among cultivars. Qiangfeng was the highest and Xinxing was the lowest, while others cultivars were between Qiangfeng and Xinxing.Tomato cultivars were inoculated with R.solanacearum with the pouring method of the adult’s hurt root. The result showed: Xinxing, Xiazuanshi, Huangshanyihao were resistant cultivars and the resistance indexes were 12.9,12.3,10.9 respectively. Huangshanerhao was middle–resistant cultivar and the resistance index was 8.9.While Qiangfeng was susceptible cultivar and the resistance index was only 2.5.Five defensive enzymes’ activities in leaves of tomato were under homeostasis without inoculation in seedling. The enzyme activities of POD,PPO and PAL in leaves of all cultivars ascended after inoculation. The enzyme activities of POD,PPO and PAL of Xinxing, Xiazuanshi, Huangshanyihao, Huangshanerhao were always higher than those of CK after inoculation, and the ascending speed ,the largest increasing rate, the peak values of the four cultivars were higher than those of Qiangfeng. The enzyme activities of POD,PPO and PAL of Qiangfeng in early days was higher than those of CK after inoculation, while was lower than those of CK in late days after inoculation. The changes <WP=9>of enzyme activities of SOD and CAT in leaves of all cultivars were turbulent and were absence of orderliness after inoculation. So, the three enzymes (POD, PPO, PAL) of leaves of tomato could be used as assistant guidelines of filtrating the resistance cultivars in early phase after inoculation with R.solanacearum, while SOD and CAT needed more studies.Five defensive enzymes activities in leaves and roots of tomato were under homeostasis without inoculation in adult. They fluctuated in a certain scope , but the extent was small. The enzyme activities of POD and PAL in leaves and roots of resistant cultivars and middle–resistant cultivar were higher than those of the susceptible cultivar without inoculation. The enzyme activities of POD, PPO, PAL, SOD in leaves and roots of all cultivars ascended after inoculation. The PAL and SOD were more susceptive than others and their activities peaks appeared earlier than others’. The enzyme activity of PAL appeared two peaks, while others appeared only one peak. The peak values and the largest increasing rates of enzyme activities of POD，PPO，PAL in roots of all cultivars were higher than those of leaves, while SOD was reverse to others. As a whole, the activities of four enzymes in leaves and roots of resistant cultivars and middle–resistant cultivar were h更多还原