Influence of Procecidochares utilis stone parasitism on tolerance and physiological response of native and invasive populations of Ageratina adenophora (Sprengel) R. King & H. Robinson.
Objective: The tolerance of the invasive plant Ageratina adenophora (Sprengel) R. King & H. Robinson parasitized by Procecidochares utilis Stone were studied to compare its physiological response of native and invasive populations, and to provide theoretical basis for the biological control of A. adenophora. Method: Measured the leaf physiological activity of A. adenophora from native (Mexico) and invaded (China) populations at the feather window [proline (Pro), malondialdehyde (MDA), polyphenol oxidase (PPO), phenylalanine ammonia-lyaseenzymes (PAL), catalase (POD) and superoxide dismutase (SOD)activities], as well as growth indexes such as plant height, total biomass, root-to-shoot ratio and specific stem length after all emergence, the differences of resistance and tolerance of A. adenophora under the parasitism of P. utilis were analyzed. Result: Under the parasitic conditions of P. utilis, the total biomass, stem biomass ratio and root-shoot ratio of A. adenophora invasive population increased significantly by 37.80%,15.38% and 21.77%, respectively (P < 0.05, the same below). The activities of PAL, POD and SOD were significantly reduced by 46.91%, 46.60% and 37.52% respectively compared with the native. However, there was no significant difference in the PPO activity of A. adenophora between invasive population and native population after parasitism (P > 0.05). The content of Pro and MDA of A. adenophora invasive population increased significantly by 66.30% and 145.08% compared with the native. Conclusion: The A. adenophora may change the resource allocation strategy after invasion, the invasive population of A. adenophora increase tolerance to the parasitism of P. utilis, while reduce the defense response to the parasitism of P. utilis. Defense strategy has changed.