大叶冬青叶片叶绿素荧光特性研究

Chlorophyll fluorescence characteristics of Ilex latifolia

对大叶冬青叶片主要叶绿素荧光参数的季节日变化进行了测定。结果表明,所测定的几个叶绿素荧光参数在春季和秋季的日变幅小。Fm、Fm′、Fv、Fv/Fm、Fm/F0、Fv/F0在夏季8：00~18：00呈现明显先降后升的规律,其最低值出现在14：00左右,而NPQ则呈现先升后降的规律,其最高值出现在12：00左右。Fm、Fm′、Fv、Fv/Fm、Fm/F0、Fv/F0在冬季一天中的变化呈先升后降的单峰曲线,其最高值出现在14：00左右,而NPQ在一天中的变化情况则正好相反,其最低值出现在14：00左右。冬夏季节的Fv/Fm、Fm/F0和Fv/F0显著低于春秋季节,表明大叶冬青冬夏季节叶片PSⅡ反应中心电子传递效率和潜在活性显著低于春秋季节。NPQ参数在冬季和夏季显著高于春秋季节,表明大叶冬青在冬季和夏季吸收的光能有更大比例用于耗散而保护自身的光合机构。相关分析表明,NPQ在春、夏和秋季与其大气相对湿度呈显著负相关,与气温和光照呈显著正相关,而在冬季则与其气温呈显著负相关。夏季的Fm/F0、Fv/F0、Fv/Fm与其气温和光照呈显著负相关,而与大气相对湿度呈显著正相关。

Abstract： The diurnal changes of chlorophyll fluorescence parameters ofllex latifolia in different seasons were studied in this paper. As results, the daily change range of every chlorophyll fluorescence measured in spring and autumn was smaller than that in summer and winter. In summer, the values of Fm （maximal fluorescence）, Fro＇ （actual maximal fluorescence）, Fv （variable fluorescence）, Fv/Fm （optimal/maximal photochemical efficiency of PS II）, Fm/Fo （electron transfer rate）, and FdFo （potential activity of PS II ） from 8：00 to 18：00 obviously showed a descend- ing-ascending trend with the lowest value occurred at about 14：00, but the value of NPQ （non- photochemical quenching） from 8：00 to 18：00 in summer obviously presented a ascending-descending trend and the highest value was detected at about 12：00. The daily change of Fm, Fm＇, Fv, Fv/Fm, Fm/Fo, and Fv/Fo in winter appeared to be a sin- gle peak and the highest value appeared at about 14：00. The daily change trend of NPQ in winter, however, was con- trary to those parameters mentioned above and the lowest value appeared at about 14：00. The value ofFv/Fm, Fm/Fo, and Fv/Fo in spring and autumn were obviously higher than those in summer and winter, indicating that the electron transfer rate and potential activity of PS II in spring and autumn were higher than those in summer and winter. On the contrary, the value of NPQ in winter and summer was obviously higher than that in spring and autumn, which showed that higher proportion of light energy absorbed from the sun in winter and summer were used for avoiding the destruction of photosynthetic tissue through hot dissipation. In spring, summer, and autumn, a closely positive and negative correlation was found between the value of NPQ and the value of illumination and air moisture, respec- tively. In summer, there was a close negative correlation between the value ofFm/Fo, Fv/Fo, and F.,/Fm and the value of air temperature and illumination, respectively. However, the correlation between the value of Fm/F0, Fv/F0, and Fv/Fm and the value of air moisturewas distinctly positive in summer season.