Study On The Rapid Induced Resistance And Chemical Signals From Pinus Massoniana

Dendrolimus punctatus Walker is the most known pest of Pinus massoniana and Pinus elliottii tree species in Southern China. Its occurrence is cyclical. This dissertation has emphasized on the physiological and biochemical changes of the rapid induced resistance and identification of signals from Pinus massoniana, which may lay the foundation in understanding the stress reaction mechanisms and scientific basis for an effective ecological management of D. punctatus Walker.Volatile organic compounds (VOCs) from P. massoniana and P. elliottii under different growth environments were collected using dynamic headspace collection methods and identified by TCT-GC/MS.The results indicated that terpenes were the dominant VOCs released from P. massioniana and P. elliotii, in which a-pinene and β-pinene covered 80% of total VOCs. The ratio of α-pinene to β-pinene was 4:1 in Pinus massoniana and 1:2 in Pinus elliottiia. Oxygenated VOCs and the others were less abundant. The relative contents of Limonene, β-phellandrene, β-caryophyllene and Germacrene D were significantly higher in P. elliottii than in P. massoniana, which resulted in the differences of chemical fingerprint of the two host plants odor.The emission of major VOCs followed a diurnal cycle with release rates increased during the light period and decreased during the dark period. As temperature rose and humidity decreased, the emission rate of VOCs increased.The result of VOCs from P. massioniana in woodland indicated that different damage mode and degrees considerably influenced the changes of induced volatile products from leaves. Although volatile substances were highly released earlier in artificially-damaged (AD) leaves, they were significantly less...