Plant resistance is divided into constitutive resistance and induced resistance. Constitutive resistance is an inherent characteristic of plants, which depends on different genotypes. Although the degree of resistance is affected by different environmental conditions, it always exists in plants and induced resistance is always studied at the plant level. eater, which refers to the response of eaten plants to affect the behavior of the herbivore or reduce its preference (Agrawal et al., 1999). It is a phenomenon of resistance similar to the immune response (Agrawal, 1998a), can only be a phenomenon of resistance. It is expressed when encountering external factors, such as damage, feeding by herbivores and infection by pathogenic bacteria. Therefore, induced resistance has an intermittent effect (Lou Yonggen et al., 1997). For this reason, Agrawal et al. (1999a) qualifiedhas optional resistor induced resistance. Constitutive resistance and induced resistance are evolved traits rather than primitive traits (Thaler et al., 1997).
Constitutive resistance is a horizontal study of plant resistance, while induced resistance is a vertical study of plant resistance. On a material basis, the two are consistent, both regarding plant morphology, nutritional quality, and the negative effects of secondary compound accumulation on insect herbivores (Strong et al., 1990; Smith, 1992), but compositional strength is relatively fixed. , and the induced resistance is a dynamic characteristic with obvious spatiotemporal effects (You Minsheng et al., 2000). Constitutive resistance is fundamentally negative for herbivorous insects, while induced resistance not only has a negative impact, but also has a positive effect in certain areas.in this case, called induced sensitivity; the defensive effects of induced resistance and constitutive resistance are also different (Underwood et et al., 2000; 2002a). In terms of resistance distribution, constitutive resistance generally extends throughout the plant, while induced resistance is localized and plant-wide (Baldwin, 2001). Induced resistance and constitutive resistance are significantly affected by environmental conditions, such as the expression of constitutive resistance and induced resistance in loblolly pine (Pinus taeda) (Lombardero et al., 2000).