叶黄素循环和光呼吸对生姜光抑制破坏的防御作用

田间生姜的光呼吸速率随光强的增加而升高，随季节和生长期的进展而降低，其日变化进程基本与ＰＦＤ同步，峰值一般出现在１０：００－１２：００；遮荫可明显降低Ｐｒ。用Ｐｒ抑制抑制Ｐｒ后光抑制加重，光化学效率和光合速率降低。

Role of the Xanthophyll Cycle and Photorespiration in Protecting the Photosynthetic Apparatus of Ginger Leaves from Photoinhibitory Damage

Using a HPLG and a portable ADC photosynthetic gas analysis system,we observed the seasonal and diurnal changes of photorespiration (Pr) and xanthophyll (L) cycle in ginger leaves under field conditions so as to understand the role of L and Pr in defending leaves against photoinhibitory damage.The results were as follows:the seasonal and diurnal changes of Pr and L of ginger leaves were marked,Pr in 14,August was higher than that in 29,September.Pr showed a diurnal change in response to PFD,and its peak was around 10:00~ 12:00.Pr declined with increasing shade extent.The L cycle showed a diurnal variation in response to PFD,xanthophyll cycle pool (A+Z+V) and its key component (A+Z) increased during mid-day period,and its peak was around 12:00.The content of A+Z and the size of xanthophyll cycle pool in different months showed a trend of 14/8>29/9>1/7.The content of A+Z+V and A+Z reduced as increase of shade.The above results illustrated that Pr and xanthophyll cycle had a positive role in dissipating excessive light energy and in protecting photosynthetic apparatus of ginger leaves from mid-day high light stress.