Releasing Variation And Effects On Airborne Microbes Of Volatile Organic Compounds From Osmanthus Fragrans

In order to research the composition, dynamic variation and effects on the growth of airbornemicroorganisms of the volatile organic compounds (VOCs) from Osmanthus fragrans, the scientificdatas were provided to landscape application of O. fragrans from the perspective of chemical ecology.With multidisplinary methods, phyto-chemecology, physiological plant ecology and microbiology, wecould analyze the composition and dynamic variation of VOCs in fresh flowers and leaves of four O.fragrans cultivar groups, O. fragrans Luteus Group, O. fragrans Albus Group, O. fragrans AurantiacusGroup, O. fragrans Siji Group, were analyzed using dynamic headspace collecting and TDS-GC-MS.The numbers of airborne microorganisms (bacteria, fungi, actinomycetes) in different months in thestands of O. fragrans varieties were investigated using the method of natural sedimentation, and thebacteriostasis experiment of extraction liquid from leaves of O. fragrans and VOCs monocase werestudied. The results were as follows:1. The composition and diurnal variations of VOCs in fresh flowers of four O. fragrans cultivargroups was analyzed. Results showed that the major VOCs were terpenoids in differet time of day, O.fragrans Luteus Group(Relative content96.54%), O. fragrans Albus Group(83.97%) and O. fragransSiji Group(85.79%)in the highest level at12:00, O. fragrans Aurantiacus Group(91.51%) in the highestlevel at14:00. the major terpenoids were as follows: β-pinene, D-limonene,(E)-β-ocimene,(Z)-β-ocimene,(E)-linalool oxide, β-linalool, α-Ionone, and β-Ionone in O. fragrans Luteus Group andO. fragrans Siji Group; β-Pinene,(Z)-β-ocimene,(E)-linalool oxide,(Z)-linalool oxide, α-Ionone, andβ-Ionone in O. fragrans Albus Group; β-pinene, D-limonene,(Z)-β-ocimene,(E)-β-ocimene,(E)-linalool oxide,(Z)-linalool oxide, β-linalool in O. fragrans Aurantiacus Group.(Z)-acetate-3-hexen-1-ol(6.9%) were also higher in four O. fragrans varieties.2. The composition and seasonal variations of VOCs in leaves of four O. fragrans cultivar groupswere analyzed. Results indicated that the major VOCs were aldehydes compounds in spring, whichmainly include Hexanal, Benzaldehyde, Octanal, Nonanal, and Decanal, more than30%in the VOCs ofthe total content; more than30%in the major VOCs were (Z)-acetate-3-hexen-1-ol of ester compoundsin summer and autumn; besides, more than20%in the VOCs were aldehydes compounds in O. fragransLuteus Group and O. fragrans Siji Group in autumn, and the relative content of aldehydes compoundsmore than ester compounds in O. fragrans Aurantiacus Group. VOCs constituents and relative contentfrom the different leaves of O. fragrans varieties in different seasons were different.3. The numbers of airborne microorganisms in the stands of four O. fragrans cultivar groups weredynamically variational in different months all years. In March, May, July, September, November, andJanuary, the numbers of bacteria in the stands of O. fragrans Luteus Group were reduced by46.60%,48.28%,67.64%,34.61%,26.00%, and31.00%(P<0.01), respectively, compared with the control ofopen ground, and the numbers of bacteria in the stands of three other O. fragrans cultivar groups alsowere reduced in different months, compared with the control of open ground. In March, July, September,and January, the numbers of fungi in the stands of O. fragrans Luteus Group were reduced by33.50%, 38.84%,34.13%, and59.34%(P<0.01), respectively, compared with the control of open ground. Thenumbers of actinomycetes in the stands of four O. fragrans cultivar groups were significantly reduced.The extraction liquid from leaves of four O. fragrans cultivar groups could inhibit the growth ofairborne microorganisms, inhibitory ability of bacteria and actinomycetes was enhanced correspondingto the increase of extraction liquid concentration. The concentration of20mg/ml inhibited the bacteriabetween70%and90%, inhibited the actinomycetes get to100%. Different concentrations of extractionliquid inhibited the fungi were significantly different. The concentration of0.2%monomers ofD-limonene and β-pinene could inhibit the growth of bacteria and fungi, and β-pinene could inhibit thegrowth of actinomycetes. The different concentration of Ocimene could inhibit the growth of airbornemicroorganisms. The concentration of0.1%and0.2%of Nonanal, Decanal and Benzaldehyde couldsignificantly inhibit the growth of airborne microorganisms.