金龟子绿僵菌对苜蓿生长的影响及对苜蓿抗蚜性的诱导作用

为明确金龟子绿僵菌Metarhizium anisopliae在促进植物生长和提高植物抗性方面的作用，以金龟子绿僵菌拌土种植紫花苜蓿Medicago sativa，于室内测定植株的生长参数、苜蓿斑蚜Therioaphis trifolii的取食选择性及其发育历期和繁殖力。结果表明，金龟子绿僵菌处理后7 d，植株株高比对照显著增加了0.87 cm；处理后14 d，植株分枝数为3.88个，根长为54.67 mm，均显著高于对照。株龄14 d的植株接入苜蓿斑蚜，至株龄28 d时，金龟子绿僵菌处理的植株株高、分枝数和根长均较对照显著增加；同时生物量、叶绿素含量和类胡萝卜素含量也有不同程度的升高。选择性试验结果显示，24 h内选择并驻留在金龟子绿僵菌处理植株叶片上的苜蓿斑蚜数量较对照显著减少28.57%。以金龟子绿僵菌处理的植株叶片饲喂苜蓿斑蚜，1～4龄若虫的发育均有所减缓，各龄若虫的发育历期均较对照叶片饲喂的各龄若虫有所延长，而成虫寿命较以对照叶片饲喂时显著缩短了30.09%，总生命历期显著缩短了18.83%。表明金龟子绿僵菌促进了紫花苜蓿植株的生长，同时增强了植株对苜蓿斑蚜的耐害性、排趋性与...

Effects of entomopathogenic fungus Metarhizium anisopliae on alfalfa growth promotion and anti-aphid induction

To determine the role of entomopathogenic fungus Metarhizium anisopliae in promoting plant growth and improving plant resistance, alfalfa (Medicago sativa) was planted in soil mixed with M. anisopliae. Several growth parameters of the alfalfa plants were measured in the laboratory, along with the feeding selectivity, development, and fecundity of the aphid Therioaphis trifolii. The results showed that plant height significantly increased by 0.87 cm compared to the control group after seven days of fungal treatment. After 14 days, the number of branches was 3.88 and root length was 54.67 mm, both significantly higher than in the control group. When 14-day-old plants were exposed to aphids, the branch count and root length continued to increase, significantly exceeding the control group by the time the plants were 28 days old. Meanwhile, biomass, chlorophyll, and carotenoid content also increased to varying extents. A selective test showed that the aphid numbers on alfalfa leaves treated with the fungus decreased significantly by 28.57% compared to the control group within 24 h of testing. Feeding aphids with leaves from the fungus-treated plants delayed development of the 1st to 4th instar nymphs and shortened adult lifespan by 30.09%, resulting in a significantly reduced total lifespan compared to aphids in the control group. This study suggested that M. anisopliae promotes alfalfa growth and enhances its resistance to aphids through increased damage tolerance, antixenosis, and antibiosis.