南方根结线虫不同接种密度对灯盏花抗氧化系统的影响

摘要

The growth and development of Erigeron breviscapus were studied in different time points (25/35 d) and different inoculation densities (0,500,700,1 000,1 200,1 500 individual/plant) and malonaldehyde (MDA),superoxide dismutase (SOD),peroxidase (POD) and catalase (CAT) activities in roots and leaves were studied.The resuits showed that the root knot indexes reached the maximum which were 87.2 and 65.6 at 25 and 35 d post-inoculation,respectively,when the inoculation density was 1 000 individual/plant,and the root knot index was influenced when the inoculation density was 500 individual/plant.Inoculation amount had no effect on POD activity of E.breviscapus at 25 d,which decreased first and then increased at 35 d after inoculation,and the POD activity was generally higher in the diseased leaves than that in the healthy group except at the inoculation density of 1 000 individual/plant.The inoculation density had a great effect on CAT activity in E.breviscapus.The CAT activity in roots and diseased leaves was significantly higher than that in the control at 1 000 individual/plant.The inoculation density had little effect on the content of MDA in the leaves.When the density was 1 000 individual/plant for 35 days,the effect on MDA content in roots was the highest,which was significantly higher than that of the control.Inoculation density had stronger effects on the SOD activity in the diseased leaves than in the root;the SOD activity was generally higher in the diseased leaves than that in healthy group,and the SOD activity in the diseased roots was generally lower than that in the healthy group.The results showed that the root knot index was the highest when the inoculation density was 1 000 individual/plant.When the inoculation density was greater than 1 000 individual/plant,the enzyme activity decreased gradually.In the early stage of inoculation,the root-knot nematodes were more harmful to the leaves of the light bulb,and the root hazard gradually increased with the planting time.%通过室内接种方法,测定了南方根结线虫2龄幼虫在不同接种时间(25、35 d)和不同接种密度(0、500、700、1 000、1 200、1 500头/株)下对灯盏花生长和根系及叶片丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶活性(POD)及过氧化氢酶活性(CAT)的影响.研究结果表明,南方根结线虫接种密度为1 000头/株时,接种后25 d与35 d的根结指数达到最大,分别为87.2及65.6;接种密度500头/株,对根结指数影响较大.接种后25 d,接种量对灯盏花病根与病叶的过氧化物酶活性影响不大;接种后35 d,灯盏花病根的过氧化物酶活性(POD)随接种密度的增加先降低后升高,病叶中的POD活性除了接种密度为1 000头/株时低于健康叶部外,其他均高于健康组;接种密度对灯盏花的过氧化氢酶(CAT)活性影响较大,在1 000头/株时,病根和病叶中的过氧化氢酶活性都明显高于对照.接种密度对于灯盏花叶片的丙二醛(MDA)含量影响不大,当密度为1 000头/株接种35 d对根部丙二醛的影响最大,其含量明显高于对照;接种密度对于灯盏花病叶和病根中的超氧化物歧化酶(SOD)活性影响较大,病叶中的超氧化物歧化酶(SOD)普遍高于健康组,而病根中的SOD活性普遍低于健康组.综合研究结果,当南方根结线虫接种密度为500头/株时,对灯盏花有一定危害,随着接种密度的增加,危害逐渐加重,当接种密度为1 000头/株时,根结指数最大,几种酶活性都显著高于健康植株,接种密度大于1 000头/株时,酶活性逐渐下降.接种初期,南方根结线虫对灯盏花叶部危害较大,随着种植时间的推移,对根部危害逐渐加重.