植物源昆虫拒食剂的研究与应用前景

Studies and Potential Application of the Plant Antifeedants

拒食剂可以定义为能抑制昆虫取食而不直接杀死它们的化合物。昆虫常继续留在经拒食剂处理的植物上并可能因饥饿而死。大部分植物依赖次生代谢物来防御植食性昆虫。各种研究表明协同进化的压力使植物越来越能抵抗昆虫的取食。大部分植物源拒食性次生性化合物可以分为倍半萜烯内酯类、异黄酮类、苦木素类和柠檬苦素类化合物４ 大类。虽然到目前为止关于结构与生物活性间关系方面尚未建立确实的规律，但结构与生物活性间关系的研究可以为了解发生在某些昆虫的膜受体水平上的分子过程提供线索，因而可以指导分离或合成高效拒食剂。昆虫感知拒食剂化合物可以通过刺激特定昆虫的特化的拒斥感器或者干扰接收诱食刺激化合物的神经元的正常功能实现。因为植物拒食剂是天然化合物，能在自然环境中很容易地被分解，较少环境污染，因而在ＩＰＭ 中具有重要的作用。为了开发出无公害新农药，需要进一步进行其作用机制、对环境的影响、结构与生物活性间关系、高效拒食剂的合成及田间试验等方面的研究。

An antifeedant can be defined as a chemical that inhibits feeding but does not kill the insect directly;the insect often may remain on the treated plant material and possibly may die of starvation.A majority of plant families rely on secondary plant metabolites for protection from polyphagous insects.It is evident from various studies that as a result of coevolutionary presures,plants have developed increasing resistance to insect feeders.Most antifeedant secondary plant compounds fall into one of four categories:sesquiterpene lactones,isoflavonoids,quassinoids,limonoids.Although on structure/bioactivity relationships nothing concrete has been established so far,they can shed some light on the molecular processes occurring at receptor membrane level of given in sect species and thus many potent antifeedants can either be isoalated or synthesized.Antifeedant compounds may be perceived by insect either by stimulation of specialized deterrent receptors or by distortion of the normal function of nurons which perceive phagostimulating in natural environment and thus less environmental contamination,they have a very important role in IPM.Further studies on their action mechanisms,their environmental impact,structure/activity relationships,synthesis of potent antifeedants and field tests are needed to develop new environmental friendly insecticides.