不同条件下香蕉幼苗对环境羟自由基水平的影响

在人工可控环境中,以香蕉幼苗在不同光强、不同温度、不同酸碱度条件下光系统Ⅱ叶绿素荧光参数的变化衡量香蕉幼苗光合特性的变化,同时测量培养环境中羟自由基水平以评价植物生长对环境羟自由基水平的影响。结果显示：香蕉幼苗生长的环境中羟自由基水平明显高于没有植物生长的同样环境,表明植物的生长可提高环境的羟自由基水平。环境条件变化引起香蕉幼苗叶片光系统Ⅱ叶绿素荧光参数发生明显变化,高光强、极端温度和极端酸碱条件下的叶绿素荧光参数变化显示幼苗不同程度的光抑制,同时也伴随环境中羟自由基水平的升高,二者具有一定程度的相关性。本研究证明了大气中羟自由基水平受植物生长状态的影响,指出植物生长状态与环境中羟自由基水平的密切关系,为研究大气中羟自由基水平的演变机制提供了依据。

Effect of Banana Seedlings on Hydroxyl Radical Content in Ambient Air under Different Environmental Conditions

Chlorophyll fluorescence and hydroxyl radical（·OH） content in ambient air were measured in banana seedlings growing in closed incubators in which light intensity,temperature,acidity and alkalinity were controlled.The correlation between changes in photosynthetic characters and ·OH content in ambient air was studied under different environmental conditions.Results showed that the level of ·OH was obviously higher in the incubator growing banana seedlings than in the incubators without growing plants,which indicated that the level of ·OH in ambient air could be improved by growing plants in it.Chlorophyll fluorescence parameters changed obviously under different culture conditions.Stronger light intensity,extreme cold and hot temperature,excessive acidity or alkalinity indicating different degrees of photo-inhibition in different culture conditions,suggesting a strong correlation between the level of photo-inhibition and ·OH content in ambient air.We also found that the level of ·OH increased with the degree of photo-inhibition.The affect of the plants on the level of ·OH was confirmed,and the strong correlation between the level of ·OH and the growth status of the plants was demonstrated.Further studies on the evolvement mechanism for ·OH in the atmosphere are recommended.