短枝木麻黄家系对青枯病的抗性评价与选择

为探讨短枝木麻黄(Casuarina equisetifolia)对青枯病(Ralstonia solanacearum)侵染后的生理生化响应，利用其生理生化响应指标与抗病性特征的相关性开展短枝木麻黄家系的抗病评价和选择。结果表明，26个短枝木麻黄家系褐梗小枝接种青枯病后，病情指数(DI)和相对病害强度(RDI)均存在极显著差异(P<0.01)。在接种青枯病后，家系间的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、总酚(TP)和类黄酮(Flav)差异均达显著或极显著水平，说明参试家系对青枯病抗性的变异丰富，具有较大的选择潜力。短枝木麻黄家系的病情症状与6个生理生化指标间均呈显著或极显著的负相关关系，说明青枯病侵染后防御酶活性或次生代谢物含量越高，木麻黄的病害程度越低。利用2个病情特征性状和6个生理生化指标对短枝木麻黄不同家系进行综合评价和选择，按照30%的入选率初步选出201、206、198、207、202、213、208和195号等8个抗病家系。这些抗病家系的RDI和DI比总体均值分别低25.94%和28.93%,SOD、CAT...

Resistance Evaluation and Selection of Casuarina equisetifolia Families Against Ralstonia solanacearum

In order to explore the physiological and biochemical response patterns of Casuarina equisetifolia against infection of Ralstonia solanacearum, the disease-resistant assessment and selection of different C. equisetifolia families were studied based on the correlations between physiological and biochemical traits and disease-resistant characteristics. The results showed that the disease index (DI) and relative disease intensity (RDI) of 26 C. equisetifolia families were significantly different after inoculated with R. solanacearum. The differences of superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), total phenolics (TP) and flavonoid (Flav) among the families were significant or very significant, indicating that the tested families had huge variation at resistance against R. solanacearum and great selection potential is expectable. The disease incidence and intensity of the 26 families presented negative correlation with the six physiological and biochemical indexes at significant or very significant level. It was indicated in a certain range that the more defense enzyme activities or secondary metabolite contents, the lower disease incidence and intension were detected. Two disease characteristics and six physiological and biochemical parameters were used to evaluate and select C. equisetifolia families against R. solanacearum, eight resistant families, including 201, 206, 198, 207, 202, 213, 208 and 195, were preliminarily selected according to the selection rate of 30%. The mean RDI and DI of eight resistant families were 25.94% and 28.93%, respectively, which was lower than those of overall mean values. And the activities of SOD, CAT, PAL, PPO, and contents of TP, Flav in these eight families were 11.90%, 13.50%, 24.77%, 12.71%, 25.68% and 18.76% higher than those of overall mean values, respectively. Therefore, the selected 8 families showed low disease degree, few wilting branches, and plant growth was not affected, indicating strong disease resistance and could be widely used in subsequent production.