金钟藤叶绿素荧光特征初探

The Characteristics of Chlorophyll Fluorescence in Merremia boisiana

利用叶绿素荧光技术初步观测了金钟藤在不同作用光下的光合生理特征,并对其离体叶片在低温、高温及脱水胁迫下的光能利用状况作了比较。结果显示,随着作用光强的增加,叶片Fv'/Fm'、qP和ΦPSⅡ呈下降趋势,qN和NPQ表现为上升。离体叶片在5℃处理6h后,其Fv'/Fm'、qP和ΦPSⅡ高于25℃和45℃处理的,而NPQ在5℃和45℃处理6h后明显低于对照(25℃),qN则略有降低。离体叶片脱水胁迫12h后,仍有一定的光能转化能力,但脱水24h和36h后,qP、ΦPSⅡ、qN、NPQ都明显下降。这表明金钟藤对于环境因子,如光强、温度及水分的变化具有较强的适应性,这可能是其在森林中能快速蔓延扩散的一个重要原因。

Merremia boisiana （Gagnep.） V. Ooststr. （Convolvulaceae） is an invasive plant that newly appeared in a forest plantation near Guangzhou. The photosynthesis characteristic observed by using chlorophyll fluorescence technique in this plant was examined under different actinic lights, and the light utilization was measured in detached leaves under different stress of low or high temperatures and dehydration. The results showed that the chlorophyll fluorescence parameters Fv＇/Fm＇, qP and ΦPSⅡ decreased with the increase of actinic light intensity, but qN and NPQ increased. When detached leaves were treated for 6 hours at 5 ℃, the Fv＇/Fm＇, qP and ΦPSⅡ were higher than those at 25℃ and 45℃. However, if detached leaves were treated for 6 hours at 5℃ and 45℃, the NPQ was evidently lower than those at 25 ℃ （control）, and the qN reduced a little. Being dehydrated for 12 hours, the detached leaves still had certain ability of light energy conversion. Whereas the values of qP, ΦPSⅡ, qN and NPQ were significantly decreased after the leaves were dehydrated for 24 and 36 hours. It is shown that Merremia boisiana has strong adaptability to different light intensity, temperature and water conditions, which may be an important cause of its rapid dispersal in forests.