Hu Yan-Bo, Zheng Gui-Ying, Wang Jing-Ying, Ao Hong, Sun Guang-Yu
College of Life Science, Northeast Forestry University, Harbin 150040.
Ying Yong Sheng Tai Xue Bao. 2010 Feb;21(2):300-5.
Taking the seedlings of mulberry (Morus alba) variety Menggusang as test materials, and by using chlorophyll fluorescence technique, this paper studied the effects of irradiance transition on the leaf active photochemical efficiency (phi(PS II)), apparent electron transport rate (ETR), and non-photochemical quenching (NPQ) under different light conditions, and analyzed the changes of three components of NPQ. When the irradiance was transferred from dark or weak light to sunlight, the photosynthetic quantum efficiency of full-light leaves was higher than that of weak-light leaves, the inducible time responses of full-light leaves' Psi(PS II) and ETR were faster to reach steady state as compared to those of week-light leaves', and the induction of full-light leaves' NPQ had a trend of rapid increase in the first two minutes and slow decrease subsequently. The state transitional quenching component (q(T)) of full-light leaves under high light condition made up 18% of the total non-photochemical quenching (NPQ), whereas the q(T) of weak-light leaves only amounted to 7% of NPQ, which meant that the mulberry leaves under full-light condition could adapt to the changes of light intensity by means of higher efficiency of photosynthetic quantum and greater contribution to the adjustment of light energy between photosystem I (PS I ) and photosystem II (PS II), compared to the leaves under weak-light condition.
以桑品种勐果桑的幼苗为试验材料，运用叶绿素荧光技术，研究了不同光照条件下光强转变对叶片活性光化学效率（φ(PS II)）、表观电子传递速率（ETR）和非光化学猝灭（NPQ）的影响，并分析了NPQ三个组分的变化。当光强从黑暗或弱光转变为阳光时，全光照叶片的光合量子效率高于弱光照叶片，全光照叶片的Ψ(PS II)和ETR的诱导时间响应比弱光照叶片更快达到稳态，且全光照叶片NPQ的诱导在前两分钟有快速增加的趋势，随后缓慢下降。高光条件下全光照叶片的状态转换猝灭组分（q(T)）占总非光化学猝灭（NPQ）的18%，而弱光照叶片的q(T)仅占NPQ的7%，这意味着与弱光照条件下的叶片相比，全光照条件下的桑叶能够通过更高的光合量子效率以及对光系统I（PS I）和光系统II（PS II）之间光能调节的更大贡献来适应光强变化。
