濒危植物长序榆(Ulmus elongata)幼苗叶绿素荧光特性的初步研究

用Li-6400XT便携式光合作用仪对濒危植物长序榆幼苗的各叶绿素荧光参数的日变化和快速光响应曲线进行了测定。结果发现,光系统Ⅱ(PSⅡ)的实际光化学效率(ΦPSⅡ)、电子传递速率(ETR)在整个白天阶段较稳定,下午18:00显著下降。光化学淬灭(qP)先增大后减小。非光化学淬灭(NPQ)呈现出与光化学淬灭(qP)相反的变化趋势,中午最低,说明长序榆幼苗光能利用率较高。快速光曲线表明实际光化学效率(ΦPSⅡ)和光化学淬灭(qP)随着光合有效辐射(PAR)的增大而减小,电子传递速率(ETR)和非光化学淬灭(NPQ)随着光合有效辐射(PAR)的增大而增大。使用幂函数能够很好的拟合实际光化学效率(ΦPSⅡ)和电子传递速率(ETR)随光强的变化,而对数函数能较好的拟合实际光化学淬灭(qP)和非光化学淬灭(NPQ)随光强的变化。

Preliminary Studies on chlorophyll fluorescence characteristics of endangered plant Ulmus elongata seedlings

Diurnal variations of chlorophyll fluorescence parameters and rapid light curves of endangered plant Ulmus elongata seedlings were determined by using Li-6400XT portable PhOtosynthesis system. The results showed that the actual photochemical efficiency（φPSⅡ）, electron transport rate（ETR）of photosystem Ⅱ （PSⅡ）were stable throughout the daytime, and decreased significantly at 18：00 pm. Photochemical quenching （qP）increased firstly at morning and then decreased after midday, non-photochemical quenching （NPQ）showed the opposite changes, the minimum at noon, indicating that the light use efficiency of Ulrn~ elongata seedlings were high. The rapid hght curves showed that actual photochemical efficiency（φPSⅡ） and photochemical quenching （qP）decreased while the photosynthetic active radiation （PAR）increased, electron transport rate （ETR）and non-photochemical quenching （NPQ）increased while the photosynthetic active radiation （PAR）increased. The power function could fit well the actual photochemical efficiency （φPSⅡ）and electron transport rate （ETR）with the light intensity changes, while the logarithmic function could fit well the actual photochemical quenching （qP）and non-photochemical quenching（NPQ）.