关键词: 丛枝菌根真菌, 根内根孢囊霉, 摩西斗管囊霉, 复合接种, 青山杨, 美国白蛾

Abstract:

【Objective】 In order to study a new way of biological control of pests on Populus pseudo-cathayana × P. deltoides leaves, the effects of compound inoculation with arbuscular mycorrhizal (AM) fungi on the resistance of P. pseudo-cathayana×P. deltoides leaves to Hyphantria cunea were investigated. 【Method】 One-year-old P. pseudo-cathayana × P. deltoides cuttings were inoculated with Rhizophagus intraradices (RI) and Funneliformis mosseae (FM) by single and mixed inoculation (M) in a greenhouse, with no inoculation (CK) as the control. The chemical defense ability of secondary metabolites, defense enzymes and protease inhibitors in poplar leaves was determined, and the larva of H. cunea was used as a bioassay object to determine its anti-insect effect.【Result】 In 120 days, the mycorrhizal infection rate, arbuscular growth rate and number of vesicles in the root of the M group were higher than those of the FM and RI groups. Meanwhile, the M group could improve the chemical defense ability of the leaves of P. pseudo-cathayana × P. deltoides to a certain extent. The contents of total alkaloids and cellulose and the activities of peroxidase (POD), catalase (CAT), lipoxygenase (LOX), polyphenol oxidase (PPO), chymotrypsin inhibitor (CI) and trypsin inhibitor (TI) in leaves were significantly higher than those in the RI, FM and CK groups (P<0.05). The food intake, fecal output, cellulase activity, acetylcholinesterase (AchE) activity and multifunctional oxidase (MFO) activity of the third instar larvae in the M group were significantly lower than those in the FM, RI and CK groups (P<0.05). The body length, food availability, trypsin activity, carboxylesterase (CarE) activity, and glutathione S-transferase (GSTs) activity of the third instar larvae were significantly higher than those of the RI and FM groups (P<0.05). The food consumption rate and α-amylase activity of the third instar larvae did not significantly differ from those of the RI group, and the body weight of the third instar larvae did not significantly differ from those of the FM group. Body weight, food intake, food consumption rate, cellulase activity, GSTs activity, CarE activity, AchE activity and MFO activity of the fourth instar larvae were significantly lower than those of the FM, RI and CK groups (P<0.05), the fecal output of the fourth instar larvae was significantly lower than that of the RI and CK groups (P<0.05), and the trypsin activity of the fourth instar larvae was significantly higher than that of the other three groups (P<0.05). The body length and food availability of the fourth instar larvae did not significantly differ from those of the RI group, and the α-amylase activity of the fourth instar larvae did not significantly differ from those of the FM and RI groups. The body length, body weight, food intake, fecal output, food utilization, α-amylase activity, cellulase activity, GSTs activity, CarE activity, and MFO activity of the fifth instar larvae were significantly lower than those in the FM, RI and CK groups (P<0.05). The food consumption rate of the fifth instar larvae was significantly lower than that in the FM and RI groups, and the AchE activity of the fifth instar larvae was significantly lower than that in the FM group (P<0.05). The trypsin activity of the fifth instar larvae was significantly higher than that of the other three groups (P <0.05).【Conclusion】 The mixed inoculation of RI and FM could induce the chemical defense performance of P. pseudo-cathayana × P. deltoides leaves in the aspects of secondary metabolites, defense enzymes, and protease inhibitors. The anti-insect performance of combined RI and FM inoculation was better than that of single RI and FM inoculation and no AM fungi inoculation and had certain inhibitory effect on the larva of H. cunea. In practical application, combined RI and FM inoculation can be prioritized.

Key words: arbuscular mycorrhizal (AM) fungi, Rhizophagus intraradices, Funneliformis mosseae, compound inoculation, Populus pseudo-cathayana ×, P. deltoids, Hyphantria cunea