落叶阔叶林释放异戊二烯的研究

Emission of Isoprene from Deciduous Forest

生物释放的烯烃是全球气候变化和温室效应研究的重要内容之一。本研究在国内首次测定了华北落叶阔叶林内１０种乔、灌木的异戊二稀释放率，分别在０—１．２８μｇ·ｇ－１·ｈ－１之间。探讨了林内异戊二烯的时空分布规律。发现高释放树种辽东栎的异戊二稀释放率呈昼夜周期性变化，在１４∶００达到１．９２μｇ·ｇ－１·ｈ－１，夜晚几乎降为０。对各环境因子进行排序：光照与异戊二稀释放率的关系最为密切（ｒ＝０．８６５０）。利用Ｂｏｗｅｎ比法，估测落叶阔叶林内异成二烯释放通量约为４８００μｇ·ｍ－２·ｈ－１。本研究采用ＧＣ－ＰＩＤ仪可直接分析未经处理的空气样。

A measurment of isoprene emission from deciduousforest was finished in North China. Three groupswere classified according to their isoprene emissionrates. The high emission species,Liaodong Oak, wasfound to have an obvious variation from day tonight. There were the maximum emission raters(1.92μg/g·h) at 14: 00 and the minimum (-0) at2: 00. In several environmental factors, light hassignificant correlation (r = 0. 86 ) with the emissionrates of Liaodong Oak. Factors could be ranked bythe following order in terms of the degrees of theirimpacts on plant emission: light > leaf temperature> ambient temperature > humidity. In deciduousbroadleaf forest, the concentration of isoprenevaried from 13.6 ×10-6 to 26.7 ×10 -6 with timeand height. By the energy balance ratio method,theflux of isoprene above canopy was about 4800 g/(m2·h ) in the morning. This research collected anew gas analysis system. Using GC-PID gas chasechromatograph, the untreated air samples could bemeasured directly.