Major Biogenic Volatile Organic Compounds Of Typical Submerged Macrophytes And The Effects Of Environmental Factors On These BVOCs Production

Biogenic Volatile Organic Compounds(BVOCs)are volatile organic compounds produced by plant metabolism.Due to their large emissions,high reactivity,participation in atmospheric chemical processes,and important physiological and ecological functions,it is of of great significance for studying on the global carbon cycle and regional atmospheric environmental quality.And researches on BVOCs have become to be a hot issue in biological sciences and atmospheric science.But so far,all the research on BVOCs is from terrestrial plants,little known is about the production and influence factors of aquatic plants,especially submerged BVOCs.In this study,the main types of BVOCs produced by common submerged plants and the effects of different environmental factors on the production of those BVOCs were studied by laboratory experiments and both qualitative and quantitative analysis methods using GC-MS.The main results are as follows:(1)36 major volatile organic compounds were detected in the 12 collected submerged plants,mainly composed of aldehydes,alcohols,ketones and other oxygenated organic compounds,such as hexanal,2-hexenal,b-ionone,b-cyclocitral,and so on.There were obvious differences in the main components of BVOCs produced by different submerged plants,but there was high similarity in BVOCs produced by the submerged plants of the same family or genus.(2)The results of the effects of different nutrient concentrations in water column on the BVOCs produced by Vallisneria natans showed that the nutrients in water column significantly affect the content of trans-2-hexenal and 2-pentylfuran produced in the V.natans.The content of BVOCs produced by V.natans at different growth stages varied significantly,which may be related to the functional redundancy of those BVOCs.The production amount of hexanal,phenylacetaldehyde,trans-2-pentenal,and benzaldehyde were higher throughout the growth cycle of V.natans.The analysis of principal components showed that the BVOCs produced by V.natans at the seedling stage in eutrophic environment and the decay stage in poor-nutrition environment was quite different from other groups.(3)As for the effects of light intensity on the production of BVOCs by V.natans,the results showed that different light conditions could significantly affect the content of2-n-pentylfuran,phenylacetaldehyde,nonanal,2,6-nonadienal,(2E,6Z)-and b-ionone produced by V.natans.As for the 2-n-pentylfuran and phenylacetaldehyde produced by V.natans,their content were significantly higher under the 40% shading condition than that under the 70% shading condition and that of the control group.This may be related to the adaptability of V.natans to light.Shading treatment reduced the total amount of BVOCs at the mature stage of V.natans,but increased the BVOCs produced at the seedling stage and the decay stage.generalized linear mode analyses showed thatthe dissolved oxygen and water temperature significantly affect the content of BVOCs produced by V.natans.(4)The experiment on the effects of temperature on the BVOCs produced by Potamogeton crispus showed that,the content of hexanal,phenylacetaldehyde,b-cyclocitral and b-ionone was higher than other volatile organic compounds,but the content of 1-penten-3-ol waslowest.Different growth stages had significant effects on the content of all BVOCs produced by P.crispus.The total amount of BVOCs produced under the four kinds of warming treatments at the seedling stage was higher than that of the control treatment;and the total amount of BVOCs produced under W treatment,H treatment and R treatment at mature stage was greater than that under the control treatment.Temperature had significant effects on the content of 1-penten-3-ol,hexanal,phenylacetaldehyde,trans-2-hexenal,and 2,6-Nonadienal,(2E,6Z)-produced by P.crispus.The W treatment,which simulated the extreme climatic events of making winter warm in southern China,had a greater impact on the content of such BVOCs.The possible reason may be that warming in winter and spring significantly affect the phenology of P.crispus.Correlation analysis and CCA analysis showed that there were significantly correlationship between p H,turbidity,electrical conductivity and the content of chlorophyll and the content of BVOCs produced by P.crispus.