不同苜蓿种质材料对茎点霉叶斑病的抗性评价

为了明确不同苜蓿材料（Medicago Sativa）对茎点霉叶斑病的抗性，对来自国内外的30份苜蓿材料进行了苗期抗病性评价，采用紫外分光光度计比色法，对不同抗感病材料体内的苯丙氨酸解氨酶（PAL）、过氧化氢酶（CAT）、过氧化物歧化酶（SOD）活性变化进行了研究。结果表明：不同苜蓿材料对茎点霉叶斑病的抗病性存在显著差异，各材料间病情指数（4.28~51.65）变化较大，其中抗病性最强的是来自内蒙的‘敖汉苜蓿’，感病性最强的是来自陕西的‘陕西苜蓿’，中抗材料有10份。接菌前，各材料间CAT，SOD活性差异显著（P<0.05），而PAL活性差异不显著；接菌后，3种酶活性均比接菌前有所升高，CAT和PAL呈先增后减的趋势，SOD活性呈依次递减趋势；同一材料在接菌后第4，8，12天3种酶活性也表现显著性差异（P<0.05）。

Resistance Evaluation of Different Alfalfa Materials on Phoma Leaf Spot

In order to define the resistance against alfalfa phoma leaf spot, the resistance evaluation was conducted with 30 alfalfa materials from China and abroad at seedling stage. Activities of phenylalanine ammonia lyase (PAL), catalase (CAT) and superoxide dismutase (SOD) were studied by using ultraviolet spectrophotometer colorimetric method. The results showed that the resistances of different materials had marked differences against the alfalfa phoma leaf spot, the disease indexes of 30 materials were ranging from 4.28 to 51.65, of which Medicago sativa Aohan come from Inner Mongolia was highly resistant and M. sativa Shanxi come from Shanxi was highly sensitive, 10 cultivars were moderately resistant. The test of CAT and SOD activities showed significant differences among each materials before inoculation (P<0.05), while PAL activities were not. The activities of three enzymes were increased after artificially inoculated with the pathogen of Phoma medicaginis, CAT and PAL activities were first increased then decreased. SOD activities showed a descending trend. These enzymes activities had significantly different among the same material at the 4th, the 8th, the 12th days after inoculation (P<0.05).