交让木叶绿素荧光特性的研究

Chlorophyll fluorescence characteristics of Daphniphyllum macropodum

对不同季节交让木叶片叶绿素荧光参数的日变化进行了测定。结果表明,交让木各叶绿素荧光参数在春季和秋季的日变化幅度小。夏季8:00～18:00,F0(最小荧光)和NPQ(非光化学淬灭系数)呈现先升后降的规律,最大值分别出现在12:00和14:00,而Fm(最大荧光)、Fm′(光适应下的最大荧光)、Fv(可变荧光)、Fv/Fm(PSⅡ最大光能转换效率)、Fm/F0(电子传递效率)、Fv/F0(PSⅡ潜在活性)则呈现先降后升的规律,12:00出现最小值。冬季8:00～16:00,F0日变化幅度较小,而Fm、Fm′、Fv、Fv/Fm、Fm/F0、Fv/F0的日变化则呈现先升后降的单峰曲线,最大值出现在12:00～14:00之间,而NPQ在一天中的变化情况则正好相反,最小值出现在12:00～14:00。春季和秋季的Fv/Fm、Fm/F0和Fv/F0明显高于夏季和冬季,表明交让木在春季和秋季叶片PSⅡ光能转化效率、电子传递效率和潜在活性都明显高于夏季和冬季。交让木夏季和冬季叶片的NPQ参数明显高于春季和秋季,表明交让木叶片在夏季和冬季吸收的光能有较大比例用于耗散而保护自身的光合机构。

The daily changes of chlorophyll fluorescence parameters of Daphniphyllum macropodum in different seasons were studied in this paper.The results indicated that the daily change range of every chlorophyll fluorescence parameter in spring and autumn was small.The values of F0（minimal fluorescence）and NPQ（non-photochemical quenching）from 8：00 to 18：00 in summer presented a ascending-descending trend and the highest value was at 12：00 and 14：00 respectively,but the values of Fm（maximal fluorescence）,Fm′（actual maximal fluorescence）,Fv（variable fluorescence）,Fv/Fm（optimal/maximal photochemical efficiency of PSⅡ）,Fm/F0（electron transfer rate）and Fv/F0（potential activity of PSⅡ） from 8：00 to 18：00 in summer obviously showed a descending-ascending trends,and the lowest values were at 12：00.The daily change of F0in winter was small,but the values of Fm,Fm′,Fv,Fv/Fm,Fm/F0 and Fv/F0 from 8：00 to 16：00 in winter,however,presented single peak and the highest value was between 12：00 and 14：00.The daily change trend of NPQ in winter,however,was contrary to those parameters mentioned above and the lowest value was between 12：00 and 14：00.The fact that the values of Fv/Fm,Fm/F0and Fv/F0in spring and autumn were obviously higher than those in summer and winter showed that the maximal photochemical efficiency,the electron transfer rate and the potential activity of PSⅡin spring and autumn were more effective.On the contrary,the values of NPQ in winter and summer were obviously higher than those in spring and autumn,indicating that higher proportion of light energy absorbed in winter and summer was used to avoid the destruction of photosynthetic tissue through hot dissipation.