赤拟谷盗成虫为害对小麦挥发性物质的影响

Effect of Tribolium castaneum adults infestation on volatile compounds from stored wheat

为了明确害虫发生与储藏小麦挥发物的关系,采用顶空固相微萃取结合气质联用技术研究了起始虫口密度分别为0、6、12、18头/kg赤拟谷盗成虫为害小麦不同时间后挥发性物质种类、含量及成分的变化情况。结果表明:被赤拟谷盗成虫为害后的小麦挥发性物质主要为烃类、醇类、醛类、酸类、酯类和其他物质,小麦被为害20 d时出现了酮类物质;随着为害时间的延长,小麦挥发性物质总含量增加,烃类物质含量随虫口密度的增加先降低后升高,酸类物质含量先升高后降低,醇类和酯类物质含量降低,酮类物质含量略有升高,但变化不明显;不同初始虫口密度赤拟谷盗成虫为害后的小麦主要特征挥发性物质为棕榈酸异丙酯、2-正戊基呋喃、长叶烯、苯乙醛、丙位癸内酯、苯乙酮、2,5,5-三甲基-庚烷。研究结果为通过检测储粮环境挥发物变化预测害虫发生提供了科学依据。

Wheat is the world′s largest food crop, and about 40% of the world′s population consumes wheat as their daily food. As an indispensable energy source in human daily life, wheat is extremely vulnerable to stored grain pests during storage due to its rich nutrients and other characteristics. Tribolium castaneum(Herbst) is an important grain storage pest in the world, and it often occurs in grain processing and storage places such as wheat flour and rice. In the process of grain storage, it often secretes harmful metabolites, which discolors the grain, causes changes in the composition and content of volatiles in the environment, produces peculiar smell, reduces the quality of food, and causes huge economic losses. Therefore, how to minimize the damage of stored grain pests, reduce the post-harvest loss of grain, and ensure the safe storage of grain is an urgent problem that needs to be solved in the current world food security. In view of this, headspace solid-phase microextraction(SPME) and gas chromatography-mass spectrometry(GC-MS) were used to investigate the changes in the types, components, and contents of volatile substances in the grain storage environment damaged by T. castaneum with different times in this work. The changes of types, contents, and components of volatile substances from wheat infested by the initial population densities of 0, 6, 12 and 18 T. castaneum adults/kg were investigated, respectively. The results showed that the volatile substances of wheat infested by T. castaneum were hydrocarbons, alcohols, aldehydes, acids, esters, and other substances. Ketones appeared in wheat after 20 days of infestation. With the prolonging infestation time, the total contents of volatile substances from wheat increased, and the hydrocarbons gradually decreased first and then increased with increasing population density, while the acid substances first increased and then decreased, alcohol and ester substances decreased, ketone substances increased slightly, but the change was not obvious. The characteristic volatile substances of wheat infested by different initial densities of T. castaneum adults were isopropyl palmitate, 2-n-pentyl furan, longifolene and phenylacetaldehyde, N-decalactone, 2,5,5-trimethyl-heptane and n-hexanal. The research result provides a theoretical basis for predicting the occurrence of stored grain pests by detecting the changes of volatile substances in the stored grain environment. This study also lays a foundation for the future research on the tendency selection behavior of the adults of T. castaneum on the volatile constituents of wheat flour.