关键词: 挥发物, 组分, 暴发, β-蒎烯, (+)-3-蒈烯

Abstract:

【Objective】 Dendrolimus punctatus is the most serious pest of coniferous forest in China, and it mainly damages Masson pine (Pinus massoniana), a dominant and local native tree species that is widely distributed in south China. It was found that the outbreak of D. punctatus is regular, and according to different outbreak frequencies of D. punctatus, the Masson pine forest were differentiate into non-outbreak area, occasional outbreak area, and frequent outbreak area. However, the function of physiological characters of Masson pine from different area during D. punctatus outbreak was unclear. Plant volatiles are important byproduct of trees and can mediate many important ecological processes. 【Method】 To test the needle volatile emission characters of Masson pine at different area, and explore the correlations between needle volatile emission and D. punctatus out break frequency, we selected three classical D. punctatus outbreak area, non-outbreak area in Baiyun tree farm, occasional outbreak area in QingShan tree farm, and frequent outbreak area in Shaoping tree farm, to identify and compare the composition of their needle volatiles. All these tree farms are located at Pingxiang City, Guangxi Province, China. 【Resuts】 Our results indicated that the volatiles of Masson pine needles are mainly composed of S-α-pinene, R-α-pinene, myrcene, R-β-Pinene, S-β-pinene, (+)-3-carene, α-terpinene, (+)-limonene, (-)-limonene, γ-terpinene. However, the component ratio of these volatiles from non-outbreak area in Bai Yun tree farm, occasional outbreak area in Qing Shan tree farm, and frequent outbreak area in Shao Ping tree farm are significantly different. According to the emission characters, these volatiles are distinguished into four types. The first type includes R-α-pinene and myrcene, whose emission quantities are negatively correlated to the outbreak frequencies of D. punctatus; the second type includes S-β-pinene, γ-terpinene, and (+)-3-carene, and reverse to the first type, the emission quantities of these volatiles are positively correlated to the outbreak frequencies of D. punctatus; the third type includes R-β-Pinene and (+)-limonene, whose emission quantities are significantly different among different areas, but not correlated to the outbreak frequencies of D. punctatus; the last type, including S-α-pinene, (-)-limonene, and α-terpinene didn't show significant differences among different areas. 【Conclution】 Combining our results with previous researches about behavior response of D. punctatus to different pine needles volatiles, we deduced that the compositions of pine needle volatile chemicals may influence the outbreak of D. punctatus. Furthermore, natural enemies are important controlling factors of Dendrolimus, the attractive effect of pine needle volatiles may be different among different areas, we mean that the volatile mixtures from non-outbreak area in Bai Yun tree farm and occasional outbreak area in Qingshan tree farm may attract more natural enemies of D. punctatus, and then influence the outbreak of D. punctatus. These results provided solid bases for further usages of plant volatiles to repel D. punctatus or attract their natural enemies.

Key words: volatiles, composition, outbreak, β-pinene, (+)-3-carene