Abstract:

Using TCT-GC-MS technique, the composition and relative contents of volatile compounds were analyzed in undamaged (control), insect-damaged (ID) and artificially-damaged (AD) leaves of Pinus massoniana in field at different times and levels of damage. The results showed that, although volatile substances were highly released earlier in AD leaves plants, they were significantly less abundant in AD than in ID leaves treatments. Also, the damage level considerably influenced the changes of induced volatile products from leaves. Compared with the control, the emission rate of camphene, β-pinene, phellandrene, caryophyllene and (E)-farnesene was high after 1 h in 25%～40% ID-affected leaves, whereas that of tricyclene, myrcene, camphene, β-pinene, phellandrene and caryophyllene reached its maximum after 24 h in 60%～75% ID-affected leaves. In the same manner, some volatile compounds in AD leaves treatment displayed their peak just after 1 h, but others after 24 h. AD and ID leaves at 25%～40% damage level did not exhibit an obvious regularity with time, however, in 60%～75% AD leaves, peaks of volatile substances were attained after 1 or 2 h. The results also showed that the relative contents of β_pinene increased and was higher in damaged than control plants. Β-pinene plays an important role in inducing insect resistance of P. massoniana trees.

Key words: Pinus massoniana, induce, volatile organic compounds, rapid changes