| Summary: | 碩士 === 國立中興大學 === 森林學系 === 92 === Some plants emit lots of biogenic volatile organic compounds (BVOCs）. Isoprene is one of the most abundant among them. Due to its high reactivity, isoprene plays an important role in air quality of our surroudings. Isoprene will rapidly react with NOx and produce ozone while irradiated with ultraviolet light. Ozone can be considered as a the secondary pollution, which harms the respiratory system of human beings and damages plants resulted in decreasing of crop yield. In order to reduce the concentration of ozone, it is necessary to decrease not only the amount of NOx emission, but also the amount of isoprene emission by plants. Therefore, it is felt importance to select some tree species having with its lower or non-emitting isoprene for the plantation of urban forest, industrial park forest and roadside planting.
This study was designed to disscuss independently the influence of light and temperature on isoprene emission from Eucalyptus citriodora Hook.. Photosynthetic system was used to measure CO2 fixation and stomatal conductance after enclosuring a single leaf. Solid-phase microextraction coupled to gas-chromatography/ mass spectrometry was used to monitor and identify isoprene emission. As the result, isoprene emission was increased with increasing light intensity from 200 to 1000μmol m-2s-1 as temperature fixed at 35℃,and increased with increasing temperature from 25 to 30℃ as light intensity fixed at 1000μmol m-2s-1. Isoprene emission was held at a constant rate with temperature from 30 to 35℃, and was increased with increasing temperature from 35 to 40℃ and reached its maxima at 40℃. As temperature over 40℃, isoprene emission was dropped rapidly.
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