施氮对苜蓿根茎叶光合产物分配及抗蓟马的影响  

Effects of nitrogen application on the distribution of photosynthates in roots,stems,leaves and alfalfa resistance to thrips

作　　者：曾文芳 李亚姝 崔晓宁 刘艳君[1] 胡桂馨[1] ZENG Wenfang;LI Yashu;CUI Xiaoning;LIU Yanjun;HU Guixin(College of Pratacultural Science,Gansu Agricultural University,Laboratory of Grassland Ecosystem,Ministry of Education,Sino-U.S.Centers for Grazingland Ecosystem Sustainability,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室,中-美草地畜牧业可持续发展研究中心,兰州730070

出　　处：《植物保护》2021年第2期109-115,共7页Plant Protection

基　　金：甘肃农业大学科技创新基金(学科建设基金)(GAU-XKJS-2018-012);国家自然科学基金(31960350)。

摘　　要：为了探究施氮对苜蓿抗蓟马的影响,本试验在大田网室盆栽条件下,以‘甘农3号’和‘甘农9号’苜蓿品种为材料,以牛角花齿蓟马Odontothrips loti为研究对象,设4个施氮处理(N1,N2,N3,N4)和1个不施氮的对照,评价不同施氮水平下苜蓿的受害程度,并测定苜蓿根茎叶生物量和可溶性糖含量。结果表明:1)施氮后2个苜蓿品种的受害指数均升高;受牛角花齿蓟马为害7 d后,2个苜蓿品种的受害指数均在N2处理下最高,分别比对照高39.93%和20.06%;受害14 d后,‘甘农3号’的受害指数在N3处理下最大,比对照高28.51%,‘甘农9号’的受害指数在N1处理下最大,比对照高23.97%;在同一施氮水平下,‘甘农3号’的受害指数均明显高于‘甘农9号’。2)施氮后2个苜蓿品种根茎叶的生物量增加,但叶茎比和根冠比降低,生物量更多向茎秆中分配,向叶片和根系中分配较少。3)苜蓿叶片中的可溶性糖含量随施氮量的增加而减少,而茎秆和根系中的可溶性糖含量升高。施氮降低了苜蓿对牛角花齿蓟马的抗性,促进了苜蓿根茎叶的生长,但根冠比下降,致使苜蓿的再生能力和耐虫性下降;施氮后苜蓿叶片中的可溶性糖含量下降,使叶片合成防御物质的碳源不足,进而导致苜蓿对蓟马的抗性降低。To explore the effect of nitrogen application on alfalfa resistance to thrips,‘Gannong no.3’and‘Gannong no.9’alfalfa varieties and Odontothrips loti were chosen as the materials.The damage degree of alfalfa was investigated under different nitrogen application levels(N1,N2,N3,N4,CK)in net houses,and the alfalfa leaf,root and stem biomasses and soluble sugar content were determined.The results showed that:1)The damage index of two alfalfa varieties increased with increasing nitrogen application level.The damage indices of the two varieties,‘Gannong no.3’and‘Gannong no.9’alfalfa,were the highest under N2 level seven days after O.loti infection,and the damage indices increased by 39.93% and 20.06%,respectively,compared with the control.The damage index of‘Gannong no.3’was increased by 28.51% at N3 level,and the damage index of‘Gannong no.9’was increased by 23.97%at N1 level 14 days after O.loti infection.The damage index of‘Gannong no.3’was significantly higher than that of‘Gannong no.9’at the same nitrogen level.2)The biomasses of the roots,stems and leaves of two alfalfa varieties increased,but the ratio of leaf to stem and the ratio of root to shoot decreased after nitrogen application.The biomass distributed in stems was more than in leaves and roots.3)The content of soluble sugar in alfalfa leaves decreased with increasing nitrogen application level,while the contents of soluble sugar in stem and root increased.The resistance of alfalfa to the thrips was reduced and promoted the growth of two alfalfa varieties by nitrogen application,but the ratio of root to shoot decreased,which resulted in decline in the alfalfa regeneration capacity and decrease in alfalfa tolerance to thrips.The content of soluble sugar in alfalfa leaves decreased with nitrogen application,which caused insufficient carbon sources for the synthesis of defensive substances in leaves,and thus resulted in more serious damage degree of alfalfa.

关 键 词：氮 苜蓿 牛角花齿蓟马 光合产物 抗虫性 

分 类 号：S474.3[农业科学—农业昆虫与害虫防治]