元宝枫、雪松挥发物释放的昼夜节律

Diurnal Rhythm of Emission of Volatile Compounds Emission from Acer truncatum and Cedrus deodara

【目的】元宝枫、雪松是华北地区常见的绿化树种,阔叶树和针叶树的典型代表,研究其挥发物释放规律并分析其对环境的影响,通过树种合理配置,科学指导绿地游憩林建设,创造更有利于人体健康的绿地环境。【方法】采用固相微萃取结合气质联用仪(SPME-GC-MS),选择生长健康的多年生元宝枫、雪松植株,摘取当年生向阳叶片与枝叶,在7月中旬从8:00—次日5:00,每隔3 h测定其挥发物成分与含量,同时同步测定植株生长环境的温度与湿度。采用SPSS软件对各数据进行整理分析。【结果】1)元宝枫叶片挥发物主要成分是C6,C8的酯、醇、醛和萜烯类化合物,乙酸叶醇酯、乙酸己酯、3-己烯醇、3-己烯醛和β-石竹烯约占挥发物总量的70.0%以上,使叶片呈现青叶香。各化合物的释放规律不同,主要成分C8酯类化合物释放高峰在14:00,低谷在5:00;C15倍半萜类化合物释放呈现"2峰2谷"型,高峰在17:00和5:00左右,低谷出现在8:00和23:00左右。相关分析表明,3-己烯醛与3-己烯醇极显著正相关,乙酸叶醇酯与3-己烯醛、3-己烯醇极显著负相关,其他挥发物间无显著相关。2)雪松枝叶挥发物主要是萜烯类物质,相对含量达84.0%以上,主要成分是α、β-蒎烯、β-月桂烯、D-柠檬烯、β-石竹烯、吉马烯D,使雪松枝叶呈现树脂香。各化合物的释放规律亦不同,大多数单萜物质如α、β-蒎烯、β-月桂烯、D-柠檬烯等,释放高峰在14:00左右,低谷出现在23:00—次日2:00;倍半萜类物质如β-石竹烯、吉马烯D释放高峰在17:00和2:00,23:00和5:00则达最低。相关分析表明,α、β-蒎烯、β-月桂烯、D-柠檬烯等4种单萜化合物相关性较高;β-石竹烯与吉马烯D极显著相关,与单萜无显著相关。3)挥发物的释放除具有昼夜节律外也受到外界环境的影响,相关分析表明,挥发物总峰面积与温度呈正相关,与相对湿度呈负相关。【结论】元宝枫叶片挥发物以C8的酯类为主,雪松枝叶挥发物以C10,C15的萜烯类为主,这与挥发物合成途径有关,各挥发物释放具有不同的昼夜节律性。通常在一定范围内随温度升高、相对湿度减小,挥发物释放量增加。

[Objective]Most volatiles released from green plants have significant physiological activity, such as regulating plant growth,enhancing its resistance,inhibiting the growth of air microorganisms,and also producing different influences on human physiology and psychology. Acer truncatum and Cedrus deodara are common urban greening tree species,typical representative of hardwoods and conifers in Northern China. In this paper,the diurnal rhythm of volatiles released from the two species was detected and the environmental impact of the volatiles was investigated,to provide scientific reference for the urban green space recreation construction by proper tree species configuration and create the green environment more conducive to human health. [Method]The sunward leaves and branches of perennial and heathy A. truncatum and C. deodara were collected,and the volatiles were measured by using the SPME-GC-MS technique every 3 hours from 8：00 to 5：00 in the mid July. At the same time the temperature and humidity of the environment were measured. The SPSS software was used to analyze the data. [Result]1） The C6 and C8 esters,alcohols,aldehydes and terpenes were the dominant components released from A. truncatum. The 3-hexenyl acetate,hexyl acetate,3-hexen-1-ol, 3-hexenal,and β-caryophyllene accounted for 70% of the total volatiles,which made leaves give up the green leaf fragrance. Different compounds had different release patterns. The C8 esters,a major volatile,had the releasing peak at 14：00 ,and the lowest releasing point at 5：00 . The C15 sesquiterpenes appeared two peaks and two valleys of the releases,the peaks were at 17：00 and 5：00,and the valleys were at 8：00 and 23：00,respectively. The correlation analysis showed that there was positive correlation between 3-hexen-1-ol and 3-hexenal,and negative correlations between 3-hexenyl acetate with 3-hexen-1-ol and 3-hexenal. No significant correlations were found between other compounds. 2 ） The volatiles of C. deodara leaves were mainly composed of terpenes which accounted for 84% of the total volatiles. The main components were α,β-pinene,β-myrcene,D-limonene,β-caryophyllene and Germacrene D,which made the branches and leaves give up resin odor. Most of monoterpenes,such as α,β-pinene,β-myrcene,and D-limonene,had their release peaks at 14：00,and the lowest release valleys occurred from 23：00 to 2：00. Most of sesquiterpenes,such asβ-caryophyllene,and Germacrene D,had their release peaks at 17：00 and 2：00,and the release valleys at 23：00 and 5：00. The correlation analysis indicated that there were positive correlations between α,β-pinene,β-myrcene and D-limonene,and positive correlation between β-caryophyllene and Germacrene D. However,no significant correlations were found between other monoterpenes and sesquiterpenes. 3 ） The volatile release was also influenced by environmental factors,except with diurnal rhythm. Total peak area of volatiles was positively correlated with temperature and negatively correlated with relative humidity. [Conclusion]The main components of the volatiles from A. truncatum were C8 esters, and the main components of volatiles from C. deodara were C10,C15 terpenes,which were related with volatiles synthesis pathway. Different compounds had different diurnal rhythms. The volatile emission rates increased with the temperature and declined with the relative humidity.