Effects Of Exogenous Jasmonic Acid And Methyl Jasmonate On The Defensive Protein Activity Of Larix Kaempferi

In our country,Larix kaempferi is one of the main afforestation tree species introduced from Japan.It is widely introduced throughout the country,but it is vulnerable to many kinds of insect pests during its growth.Studies have shown that exogenous jasmonic acid and methyl jasmonate treatment can enhance the activity of various defense proteins in L kaempferi,thus enhancing plant resistance to insect pests.In order to search for effective and environmental control measures for L kaempferi,and to ensure the healthy and sustainable development of forestry.2-year-old L kaempferi seedlings were selected from Changlinggang Forest Farm in Ensch,different concentrations of exogenous jasmonic acid and methyl jasmonate were applied to detect the temporal changes of various defense proteins activities in the needles of L kaempferi,and to explore the effect of exogenous jasmonic acid and methyl jasmonate on the induced resistance to L kaempferi.The main results were as follows:1.Temporal changes of protective enzymes activities in needles of L kaempferi treated with exogenous jasmonic acidThe activities of POD and CAT in L kaempferi needles were significantly increased by spraying jasmonic acid,and the activities of POD and CAT increased at first and then decreased.The activity of both protective enzymes reached the peak 3-5days after spraying,and the effect of 0.1 mmol·L^-1jasmonic acid spraying was the best and the activity lasted the longest.2.Temporal changes of defense enzymes activities in needles of L kaempferi treated with exogenous jasmonic acidThe activities of PAL and PPO increased significantly in the needles of L kaempferi treated with jasmonic acid,and showed a trend of increasing at first and then decreasing.The activity of PAL reached its peak on the 3rd day after spraying jasmonic acid,and then showed a decreasing trend.The effect of 0.1 mmol·L^-1jasmonic acid was the best and the enzyme activity lasted the longest.0.01 mmol·L^-1jasmonic acid was the most effective and the activity of PPO was the longest.3.Temporal changes of protective enzymes activities in needles of L kaempferi treated with exogenous methyl jasmonateSpraying methyl jasmonate increased the activities of POD and CAT in L kaempferi leaves significantly,and the activities increased at first and then decreased.The activity of both protective enzymes reached a peak at about 3-5 days after spraying,and then showed a decreasing trend.0.01 mmol·L^-1methyl jasmonate was the most effective and the activity of POD was the longest.0.1 mmol·L^-1methyl jasmonate was the most effective and the activity of CAT was the longest.4.Temporal changes of defense enzyme activities in needles of L kaempferi treated with exogenous methyl jasmonateAfter spraying methyl jasmonate,the activities of PAL and PPO increased significantly in the needles of L kaempferi,and the activities of PAL and PPO increased and then decreased.The activity of methyl jasmonate reached the peak on the 3rd day after spraying,and then showed a decreasing trend.Among them,0.01mmol·L^-1methyl jasmonate spraying had the best induction effect on PAL and PPO and the longest duration of enzyme activity.