| Larch (Larix spp.) are the main afforestation tree species in Northeast and Inner Mongolia, which is often affected by defoliation plantation pine moth(Dendrolimus superans),serious harm to gypsy moth(Lymantria dispar)and other pests.Four years Larix olgensis seedlings as experimental materials were used to test the effects of different jasmonic acid (JA) and Methyl jasmonate(MeJA)treatments on the induced tree resistance against insect attacks in this study. Three concentrations of JA or MeJA(1,0.1 and 0.01mmol/L)were sprayed respectively on the whole larch seedling or on part of the seedling plant,and their effects on enzyme activity of following major defense proteins were measured,and their effects on Lymantria dispar growth and development.Analysis determined using Jasmonates local processing on Larix olgensis insect resistance induced systemic effects,For larch forest pest management control measures that to take economic,simple,easy to operate,ecological security,provide a scientific basis and theoretical foundation.The main results are as follows:1. Temporal variation of Larix olgensis defense protein activity induced by local spraying of exogenous JAWith local spraying exogenous jasmonic acid of Larix olgensis,can be induced to increase its defense protein activity(P<0.05),and the difference was significant.and induction effect of spraying were similar.By 0.1,1mmol/L concentration JA induced resistance in 1-10d,in 15-25d induced resistance was significantly lower than that of inducing effect of concentration of 0.01mmol/L(P<0.05).High concentration of JA,can be rapidly induced in Larix olgensis produce strong chemical defense capability,low concentration of JA induced chemical defense of Larix olgensis speed is relatively slow,but the effective duration was longer than that of high concentration of JA induced effect.2. Effects of local spraying exogenous JA induced growth and reproduction of Lymantria disparLocal spraying exogenous JA induced Larix olgensis can effectively inhibit the Lymantria dispar growth and reproduction,and the inhibition effect with whole plant spraying is similar.Feeding Larix olgensis was induced by 0.1 and 1mmol/L JA local or whole plant spraying,the Lymantria dispar larvae survival rate,3-6 instar larvae weight,male and female pupa weight and amount of eggs were significantly lower than those of the control (P<0.05),Feeding Larix olgensis was induced by 0.01 mmol/L JA local or whole plant spraying,the gypsy moth survival rate,the 3 and 4 instar larvae weight have not significant difference compared with the control (P>0.05),and the 5 and 6 instar larva weight,male and female pupa weight were significantly lower than the control (P<0.05),In addition,feeding 0.01 mmol/LJA local spraying of Larix olgensis,gypsy mothfecundity was significantly lower than the control (P<0.05).The rapid growth of Lymantria dispar was inhibited at high concentration,further explain high concentration of JA can rapid induction of Larix olgensis defense,low concentration of JA induced defense responses of Larix olgensis speed is relatively slow.3. Temporal variation of Larix olgensis defense protein activity induced by local spraying of exogenous MeJALarix olgensis was reduced by exogenous MeJA of local spraying,the untreated needle SOD,TI and CI activity were significantly higher than that of the control (P<0.05), whih the treated needle and whole spraying have not significant difference (P>0.05), PPO and PAL activity was significantly higher than that of the control (P<0.05), but significantly lower than that of the whole spraying and the treated needle (P<0.05).That MeJA local spraying can enhance of Larix olgensis defense protein activity induced by the system, but the effect is lower than that of the whole spraying induced.3 the concentration of MeJA can induced in needles of Larix olgensis defense protein activity were significantly higher than those of control (P<0.05), 1mmol/L of MeJA can effectively induce SOD,PAL and TI activity enhance,the induction effect is better than that of O.Olmmol/L (P<0.05),on PAL the effect is better than that of 0.1mmol/L induced (P<0.05);0.1 and 0.01mmol/L MeJA induced increase on PPO activity, induced effect is better than that of 1mmol/L significantly (P<0.05).3 the concentration of MeJA can induced CI activity was significantly increased, the difference was not significant (P>0.05). Description of Larix olgensis needles of different defense proteins have different response to concentration of MeJA,0.1 and 1mmol/L MeJA induced by showed better effect. Induction effect of 3 concentration of MeJA on the defense protein activity in Larix olgensis needles at least up to 20 days.4. Effects of local spraying exogenous MeJA induced growth and reproduction of Lymantria disparFeeding by 3 concentration of MeJA local spraying induced Larix olgensis, Lymantria dispar 3-6 instar larvae weight, survival rate, and the female pupa weight and fecundity of adult had reduced in varying degrees, in the same concentration of methyl jasmonate local spraying have not significant difference with whole spraying. By lmmol/L MeJA induced, gypsy moth survival rate,3-5 nstar larvae weight, pupa weight and fecundity were significantly lower than the control (P<0.05), in addition,1mmol/L MeJA local spraying induced, gypsy moth female pupa weight also significantly lower than those of the control (P<0.05); By 0.1mmol/L MeJA induced, gypsy moth larvae survival rate,3-6 instar larvae weight,male and female pupa weight and fecundity were significantly lower than those of the control (P<0.05); By 0.01mmol/L MeJA local spraying induced, gypsy moth fecundity was significantly lower than the control (P<0.05).0.1 and lmmol/L MeJA induced Larix olgensis can significantly inhibit Lymantria dispar growth and reproduction, and the inhibition effect is better than that of 0.01mmol/L, further suggesting that 0.1 and 1mmol/L MeJA had a better effect on the inducing Larix olgensis defense response.5. Comparison of local spraying of exogenous jasmonic acid and methyl jasmonate onresistance induction effects of Larix olgensisLocal spraying of exogenous 0.1mmol/L jasmonic acid and methyl jasmonate could induce that with defense of the protease activity was improved in needles of Larix olgensis, and significantly inhibited the larvae growth and reproduction of Lymantria dispar. Local spraying of 0.lmmol/L of MeJA induced enhancement of Larix olgensis in needles of PPO and CI activity is better than that of induced by local spraying of 0.1mmol/L JA(P<0.05). Compared with induced by local spraying of 0.1mmol/L JA. induced by local spraying of 0. lmmol/L MeJA after, the Lymantria dispar 5-6 instar larvae weight, male and female pupa weight and female fecundity decreased and volume were 22.4%,18.5%,11.6%,32.1% and29.2%.To sum up, the local application of exogenous JA and MeJA could induce enhancement of resistance to the system of Larix olgensis,and inhibition of Lymantria dispar growth and reproductive capacity, and the induction effect with similar to the whole plant spraying.0.1 and 1mmol/L JA and MeJA on Larix olgensis defense reaction showed induction effect better, while the local spraying of 0.1mmol/L MeJA induced effect is better than that of local application of 0.1mmol/L JA. Therefore, in pest control practice, harm suggested the use of 0.1mmol/L MeJA local spraying to control forest of Lymantria dispar. |
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