Effects Of Exotic MeSA, Leafhopper-damaging And Mechanically Piercing On The Volatile Ingredients And PAL, PPO Activity In Tea Shoots

In this dissertation, it is studied that the effect of exotic methyl salicylate (MeSA), damaging by tea green leafhopper (TGLD), and mechanically piercing (MP) on the activity of Phenylalanine ammonia lyase (PAL) and polyphenoloxidase (PPO), as well as the volatiles from the tender tea shoots. The main results follow as:1 The activity of PAL and PPO fluctuates periodically in a whole day. The activity of PAL takes on 2 peaks, occurring around 12 : 00 and 18 : 00. The least activity of PAL around occurs 6 : 00. The activity of PPO has a maximum and a minimum, occurring 16 : 00 and 4 : 00, respectively.2 Both TGLD and MP obviously affect the change in enzyme actovity of PAL in a day. After MP, the activity of PAL descend rapidly, falling to the minimum 10 h later, decreasing by 30.699%. Then the activity gradually rise, surpassing the activity value of PAL in CK 22 h, increasing by 20.565 %. After damaging by tea green leafhopper, the activity of PAL gradually rise, and rising to the maximum 8 h later;then the activity descend fluctuated, falling to the minimum around 6 : 00 next day. Compared with the natural change in enzyme activity in a day in tea shoot, the minimum activity value occur after 4 h by damage by tea green leafhopper, descending 12.984%;on the other hand, after damaging by tea green leafhopper, the activity value increase, and the maximum activity value occur after 22 h by damage by tea green leafhopper, increasing by 9.328%. Therefore, the activity of PAL in tea shoot damade by leafhopper fluctuate not as acutely as that in the natural change in enzyme activity in a day in tea shoot.3 Both TGLD and MP also affect obviously the change in enzyme activity of PPO in a day. After 6 h the activity of PPO in tea shoots damaded by tea green leafhopper take on a big raise, then increase fluctuated, and rise to the minimum around 0 : 00 next day. After that, the activity of PPO enter the next the fluctuating cycle. That affect of MP on the activity of PPO in tea shoot is different from that of TGLD. After mechanically piercing, the activity of PPO rise, and reach the bigger value 6 h later;then descend, and fall to the minimum 12 h later;increase fluctuatedly again.4 Exotic MeSA induce the acticity of PAL to increase. Among three dosages, the 400 μl gave the the strongest inducement to PAL. On the 1st, 2nd, 3rd and 4th day after treatment by 400 μl MeSA, the activity of PAL surpass that of CK by 3.68%, 25.30%, 21.23% and 27.03%, respectively. The treat methods are spraying and exposing. However, the inducing effect by spraying is stronger than that by exposing (P< 0.05) in the first day and the second day;however, the significant difference between the inducing effect by spraying and the inducing effect by exposing do not exist in the third day and the fourth day.Similarly, the exotic MeSA also induce the change in the activity of PPO in tea shoots. Among three dosages by exposure, the activity of PPO tend to decrease accompanied by the increasing of dosage, butdo not reach the significant level of P < 0.05. But after treatment by MeSA exposing, the acitivity of PPO in tea shoots always increase. As to the experiments in Beilun tea gardens in Ningbo City, the first, the second, the third and the fourth day after treatment by MeSA exposing, the activity of PPO surpass that of CK by 33.66%, 38.33%, 34.85% and 20.99%, respectively. During the spaying experiment, the exotic MeSA restrain the activity of PPO, furthermore, the restrain effect strengthen accompanied by the increasing of dosage.5 Both MP and the exotic MeSA affect the composition and the content of the volatiles of tea shoots. The ingredients in volatiles from tea shoots by MP are more than those in CK tea shoots. Compared to the volatile composition of CK tea shoots, Ethylacetate,l-Penten-3-ol, Heptanal, 1-Hexanol, [Z]-3-Hexen-1 -ol, 1 -Octanol,[Z]-Hexanoic acid,3-hexenyl ster,Nonanol,3-Cyclohexene-1 -methanol, [E]-2,6-octadienal,3,7-dimethyl, Benzyl alcohol, Nonanoic acid,methyl ester,[Z]-Butanoic acid,3-hexenyl ester are not detected in the volatiles of MP tea shoots;However, Indole.lH-Indazole, Pentenal,Ethanol,[Z]-2-Penten-l-ol are added. But the contents of those ingredients, both CK tea shoots and MP tea shoots hold, increase after treatment by MP.The quality and the quantity of the volatile compounds from tea shoots by MeSA exposuring obviously differ from those of CK. Compared to the volatile composition of CK tea shoots, beta-Myrcene/2-Hexenal,[Z]-2-Penten-1 -ol,Nonanal, Cyclohexanol,[Z]-2,6-octadien-1 -ol,3,7-dimethyl, Phenyethyl alcohol, l,6,10-Dodecatrien-3-ol,3,7,ll-trimethy, Heptanoic acid,methyl ester are detected in MeSA exposuring tea shoots, however, l-Penten-3-ol, Heptanal, Furan,2,5-dihydro,Hexanoic acid,3-hexenyl ster,[Z],3-Hexen-ol,[E], Pentanediol, 4-Hexen-l-ol,acetate are not detected in MeSA exposuring tea shoots. MeSA exposuring can raise the contents of MeSA,[E]-2-Hexenal, l,6-octadien-3-ol,3,7-dimethyl and so on.To sum up, under the inducement of exotic MeSA, or being damaged by tea green leafhopper, the content of MeSA in tea shoots increase. It propose that MeSA is an important defence signal molecules.