高等植物对甲醇的释放和利用

植物可向大气中释放一种挥发性的有机气体——甲醇,同时对这种气体可加以利用。在详细阐述甲醇的产生、释放和可能的代谢机制的基础上,通过不同浓度的甲醇溶液喷施牡丹叶片,测定其对光合作用过程及叶绿素荧光参数变化的影响。结果表明,光合作用有较大改善:光合速率明显提高,气孔导度增加,叶内CO2浓度也有一定幅度改善。叶绿素荧光参数(qN和NPQ)以及电子传递速率(ETR)发生较大改变;Fm/Fo,Fv/Fo和ΦPSII的下降可能与甲醇对牡丹叶片的双向效应(促进性和毒性)有关,这取决于喷施的浓度、次数和时间。初步的结果显示:甲醇提高光合作用速率的同时,并没有伴随光合效率和机能的改善和提高。期间的气孔导度和胞内CO2浓度的提高以及非辐射能耗散(qN和NPQ)和光呼吸的降低可能是牡丹叶片光合作用速率提高的主要原因。

Emission and utilization of methanol in higher plants

Methanol, as one of the major volatile organic compounds (VOCs) found in the atmosphere, has been proved to be emitted from leaves of most plant species. The formation, emission and metabolism of methanol in higher plants were reviewed in this paper. Photosynthetic processes and chlorophyll a fluorescence parameters were measured on peony leaves treated with different methanol concentrations. The primary results revealed that photosynthesis was greatly improved by methanol, as indicated by higher photosynthetic rates and stomata conductance (GS). Strikingly different patterns were observed for photochemical quenching (qP), non-photochemical quenching (qN and NPQ), and electron transport rate (ETR). Decreases in Fm/Fo, Fv/Fo and φPSⅡ caused by methanol revealed dual effect of methanol (stimulation or inhibition) on the peony leaves, which were determined by the concentration of methanol and time duration. The data suggested that methanol can not only serve as carbon source, but also regulate energy distribution and dissipation, especially for non-photochemical quenching and photorespiration.