短期干旱胁迫对马尾松排放挥发性有机物的影响

为探究干旱环境对BVOCs排放的影响，应用动态封闭式采样系统和热脱附-气相色谱-飞行质谱仪，对短期干旱胁迫作用下马尾松的BVOCs排放进行了实验室测量，定量分析BVOCs排放速率和排放组成的变化.结果表明，干旱胁迫时异戊二烯的排放受到抑制，排放速率降低约50%；单萜烯和倍半萜烯的排放水平增强，排放速率分别为137.85和0.98μg/（m²·h），是未受胁迫时的2.9和2.0倍.除反式-α-香柠檬烯外，干旱胁迫促进各单萜烯和倍半萜烯化合物的排放，是未受胁迫时的1.3~42.4倍，其中3-蒈烯排放的响应最敏感，α-葑烯、α-水芹烯和石竹烯的响应最弱.干旱胁迫时单萜烯和倍半萜烯的排放组成有所变化，但主导的化合物种类不变，单萜烯以α-蒎烯、香桧烯和β-蒎烯为主，占比分别为48%、17%和17%；倍半萜烯以石竹烯和长叶烯为主，占比分别为57%和34%.

Impact of short-term drought stress on volatile organic compounds emissions from Pinus massoniana

To explore the impact of drought on BVOC emissions, dynamic enclosure system and TD-GC-TOFMS were used to conduct laboratory measurements of BVOC emission from Pinus massoniana under short-term drought stress. The changes in emission rates and composition were analyzed quantitatively. The results showed that emission of isoprene was inhibited under drought stress, with a drop of around 50% in emission rate. Monoterpene and sesquiterpene emission rates were enhanced to 137.85 μg/(m²·h) and 0.98 μg/(m²·h) which were 2.9 and 2.0 times as high as those without stress, respectively. Except trans-α-bergamotene, emissions of all the detected monoterpene and sesquiterpene compounds were promoted under drought stress. Those emission rates were 1.3~42.4 times as high as those without stress. Among them, 3-carene emission had the most sensitive response to drought stress, while α-fenchene, α-phellandrene, and trans-caryophyllene had the lowest sensitivity. Under drought stress, the emission compositions of monoterpene and sesquiterpene were changed, but the dominant compounds remained the same. The main components of monoterpene were α-pinene, sabinene, and β-pinene, accounting for 48%, 17%, and 17% in the total monoterpene emissions, respectively. Trans-caryophyllene and longifolene dominated sesquiterpene emissions with contributions of 57% and 34%, respectively.