松材线虫侵染对日本落叶松生理指标的影响

Effects of Bursaphelenchus xylophilus Infestation on Physiological Indexes of Larix kaempferi

通过测定光合色素含量、渗透调节物质、苯丙氨酸解氨酶和抗氧化酶系统的动态变化,从生理生化角度探究日本落叶松对松材线虫侵染的响应规律。以3年生日本落叶松盆栽苗为实验材料,采用人工皮接法接入2 000条松材线虫,于接种后第0、5、10、20、30天时收集并测定针叶内叶绿素含量、可溶性蛋白含量、抗氧化酶[超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)]活性和苯丙氨酸解氨酶(PAL)活性等指标。结果表明:日本落叶松接种点上部和下部均检测到大量松材线虫,且下部线虫数极显著高于上部(P<0.01)。叶绿素a、b含量均在第10天时出现明显下降,随后开始上升,与对照组无显著差异。可溶性蛋白含量在接种10 d后开始逐渐上升,且显著高于对照组(P<0.05)。接种松材线虫后,SOD活性显著上升,各时间点均极显著高于对照组(P<0.01);CAT活性先小幅下降,后逐渐升高,于30 d时极显著高于对照组(P<0.01);POD活性表现为先降低后升高,且5 d后迅速升高,各时间点都显著高于对照组(P<0.05)。PAL活性呈现先升高后降低的变化规律,接种后10、20 d活性都显著高于对照组(P<0.05)。日本落叶松被松材线虫侵染后,叶绿素含量、可溶性蛋白含量、抗氧化酶和PAL活性变化与其抗病性存在密切关系,研究结果可以为日本落叶松对松材线虫抗性品系筛选和抗病机理提供参考。

The dynamic changes of photosynthetic pigment content,osmotic regulatory substances,phenylalanine ammonia lyase and antioxidant enzyme system were determined to explore the response of Larix kaempferi to the infection of Bursaphelenchus xylophilus from the physiological and biochemical perspectives.Three-year-old potted L.kaempferi was used as the experimental material.Two thousand B.xylophilus were inoculated by artificial skin grafting method.The chlorophyll content,soluble protein content,antioxidant enzymes(superoxide dismutase SOD,catalase CAT and peroxidase POD)activities and phenylalanine ammonia lyase(PAL)activities were collected and measured on the 0,5,10,20,and 30 days after inoculation.The results showed that a large number of B.xylophilus were detected in the upper and lower parts of the inoculated site of L.kaempferi,and the number of nematodes in the lower part was significantly higher than that in the upper part(P<0.01).The contents of chlorophyll a and b both decreased significantly on the 1o"day,and then began to increase,which had no significant difference with the control group.After 10 days of inoculation,the content of soluble protein gradually increased and was significantly higher than that of the control group(P<0.05).The SOD activity increased significantly after B.xylophilus inoculation,which was significantly higher than that of the control group at each time point(P<0.01).CAT activity decreased slightly at first and then increased gradually,which was significantly higher than that in the control group at 30 days(P<0.01).POD activity decreased first and then increased,and increased rapidly after 5 days,which was significantly higher than that of the control group at each time point(P<0.05).The activity of PAL increased at first and then decreased.The activity at 10 and 20 days after inoculation was significantly higher than that in the control group(P<0.05).The changes of chlorophyll content,soluble protein content,antioxidant enzymes and PAL activities were closely related to the disease resistance of L.kaempferi infected with B.xylophilus.The results of this study can provide a reference for the screening of resistance lines and the resistance mechanism of L.kaempferi infected with B.xylophilus.