| As an excellent tree species,Larix kaempferi has been widely used in various afforestation projects in western Hubei.It has a wide range of introduction and a large area.However,pests have been rampant and seriously damaged forest resources for a long time.In order to protect the ecology in the upper and middle reaches of the Yangtze River and maintain the sustainable development of forestry,environmentally friendly pest control measures are urgently needed.Plant induced insect resistance is a defense mechanism that can effectively control pest damage.The two main defensive enzymes and protective enzymes in plant leaves are phenylalanine ammonia-lyase（PAL）,polyphenol oxidase（PPO）and catalase（CAT）,Peroxidase（POD）,as a key defense protein in plants,are closely related to plant resistance.The comprehensive management of pests by studying the induced resistance of plants can provide a new approach for the ecological control of larch pests.In this study,We choose 2-year-old seedlings to study the effects of exogenous salicylic acid and local leaf pruning on induced resistance of Larix kaempferi.Using UV spectrophotometer to analysis the changes of PAL,PPO,POD and CAT activities in needles of Larix kaempferi,by leaf cutting and spraying salicylic acid.The results show:1.Exogenous salicylic acid can induce the changes of main defensive enzyme activities in Larix kaempferi.PPO and PAL is the plant’s two main defensive enzymes,which may change as a dynamic biochemical markers of plant resistance.In order to study the relationship between exogenous salicylic acid induction and the changes of PPO and PAL activities in needles of Larix kaempferi.Spraying with salicylic acid solutions of different concentrations(0.01,0.10,1.00mmol·L-1)to treat Larix kaempferi.and then detect the trend of PPO and PAL activity in needles on the 1st,3rd,5th,and 7th day.The results showed that spraying salicylic acid at three concentrations could induce the increase of PAL and PPO activities in the needles of Larix kaempferi,and changes in volatility that rise first and then fall.2.Exogenous salicylic acid can induce the changes of main protective enzyme activities in Larix kaempferi.Plants mainly protective enzymes POD,CAT,etc.,to improve activity plays an indispensable role in the defense response of the plant.Different concentrations(0.01,0.10,1.00mmol·L-1)salicylic acid Larix kaempferi seedling spraying process,the needles which significantly increased the POD activity,CAT activity trend increased first and then decreased.Where in 0.01mmol·L-1salicylic acid is preferably,the most obvious changes in the activity of POD Larix kaempferi needles inducing effect,and the value of the POD activity after induction of longer duration.3.Changes of main defensive enzyme activities induced by leaf cutting in Larix kaempferi.Leaf cutting induces expression of major defense proteins in plants.In order to study the relationship between local leaf cutting and the activity of PPO and PAL in needles of Larix kaempferi,the present study,25%,50%,75%three degrees of leaf-cutting processing amount Japanese larch seedlings.And then detect the trend of PPO and PAL activity in needles on the 1st,3rd,5th,and 7th day.The results showed the activities of PAL and PPO in needles of Larix kaempferi were significantly increased after three degrees of leaf cutting,and the persistence was better.4.Changes of main protective enzyme activities induced by leaf cutting in Larix kaempferi.when plants are injured,the protective enzymes such as POD and CAT in the cell can protect themselves to improve plant resistance.After 25%,50%,75%three levels of leaf-cutting deal with the needles of Larix kaempferi seedling,its needles CAT and POD activity significantly increased durability and good.We find that the change of enzyme activity is not proportional to the damage degree after different leaf cutting treatments. |
PDF Full Text Request