Abstract: During the long-term interactions or survival competition with biotic and abiotic environments, plants have developed a set of defensive strategies to resist adverse conditions. Two major defensive strategies, physical defense and chemical defense, were usually defined to address this issue. The physical defense strategy is adopted by plants through changing the morphological structure, such as leaf vein network structure, stem and leaf toughness, hardness, cellulose, hemicellulose and lignin content, etc; while the chemical defense strategy refers to physiological and biochemical responses, such as some secondary metabolites and defensive enzymes which often serve as a critical biochemical basis for the resistance and response to pathogens, pests and the abiotic environmental stresses. In this paper, we firstly reviewed important traits of the two distinctively defensive strategies, and then analyzed their driven mechanisms from the perspectives of biological violations, climate factors, and resource allocation in plants. The paper would, to some extent, contribute to further understanding the internal relationship between plant’s traits and environment, and also provide some references for plant’s regional adaptation, selective breeding in insect-resistant germplasm resources, and forest management.

Key words: LNA-PCR, pyrosequencing, soil amendment, soil erosion., corn root-associated bacterial community