我国西北地区夏季油松挥发物成分日变化及其影响因子研究

Diurnal variation and influencing factors of volatile organic compounds from Pinus tabuliformis in summer in Northwest area of China

【目的】探究我国西北地区夏季油松挥发物的主要成分、日变化规律及其影响因子,为构建生态保健型城市森林和人们合理选择游憩时间提供参考依据。【方法】于7月上、中、下旬选择晴朗无风的天气,连续3d在08:30,10:00,11:30,13:00,14:30,16:00和17:30,采用动态顶空吸附法采集样品,用气相色谱-质谱(GC-MS)联用技术对油松释放的挥发性有机物(VOCs)进行鉴定,分析其日变化动态;同时利用LI-6400XT光合仪测定其净光合速率、气孔导度、蒸腾速率并记录温度、湿度和光照强度,分析油松总挥发物(TVOC)含量与上述光合生理指标和气象因子的相关性。【结果】(1)油松挥发物成分包括8类62种,对人体健康有益的萜烯类化合物是其主要挥发物成分。(2)夏季油松总挥发物含量日变化曲线呈"两峰三谷"型:13:00和16:00出现高峰,08:30、14:30和17:30出现低谷;一天中,对人体健康有益的萜烯类成分含量下午高于上午,对人体有害的芳香烃化合物主要出现在08:30-10:00和13:00-14:30,但含量较低。(3)温度高、湿度低且光照强时油松释放的挥发物总量较大,反之挥发物总量较小;净光合速率、气孔导度及蒸腾速率的日变化规律与总挥发物含量的日变化一致性较强;总挥发物含量变化与温度、光照和湿度的相关性不显著,与气孔导度相关性显著,与净光合速率和蒸腾速率相关性极显著。【结论】夏季一天不同时段中,由于气象因子改变引起油松生理活动发生变化,进而导致其释放的总挥发物量不同,具体成分及相对含量也存在一定差异,但各时段主要成分皆为萜烯类化合物。

【Objective】Components,diurnal variation and influencing factors of volatile organic compounds（VOCs）fromPinus tabuliformis in summer in northwest area of China were analyzed to provide theoretical basis for selecting ecological trees for urban greening and choosing suitable recreational time.【Method】VOCs from Pinus tabuliformis in summer were collected by dynamic headspace air-circulation method at 08：30,10：00,11：30,13：00,14：30,16：00and 17：30in 3sunny and windless days in early,middle and late July,respectively.Samples were identified using gas chromatography-mass spectrometer（GCMS）to analyze their diurnal changes.Physiological characteristics including net photosynthetic rate,stomatal conductance and transpiration rate and meteorological factors including temperature,humidity and illumination were also measured to analyze correlation between total VOCs（TVOC）and influencing factors.【Result】（1）There were 62 kinds of VOCs belonging to 8categories emitted from Pinus tabuliformis,among which terpenes were the main component.（2）The diurnal variation of TVOC appeared in a shape of＂two peaks and three vales＂with peaks at 13：00and 16：00and vales at 08：30,14：30and 17：30.The content of terpenes in the afternoon was higher than that in the morning,and aromatic compounds were low with peak values at 08：30-10：00and 13：00-14：30.（3）TVOC from Pinus tabuliformis was high when temperature was high,illumination was strong and humidity was low.The diurnal variation of TVOC accorded with that of net photosynthetic rate,stomatal conductance and transpiration rate.The correlation between TVOC and meteorological factors was not significant.TVOC was significantly correlated with stomatal conductance and very significantly correlated with net photosynthetic rate and transpiration rate.【Conclusion】Due to change in physiological activity of Pinus tabuliformis caused by meteorological conditions in summer day,concentrations and components of TVOC varied significantly.Terpenes were the main components for all periods.