依赖叶黄素循环的非辐射能量耗散在防御珊瑚树叶片光抑制破坏中的作用

Role of the Xanthophyll Cycle Dependent Radiationless Energy Dissipation in Protection Against Photoinhibitory Damage in Sweet Viburnum (Viburnum odoratissimum)

使用脉冲调制荧光仪观测了珊瑚树叶片光合作用的光抑制发生与恢复过程中几个主要荧光参数(初始荧光F_0,可变荧光与最大荧光之比F_v/F_M和非光化学荧光猝灭q_E及其快组分 q_(E—fast)、慢组分 q(E—slow))的变化,以探讨非光化学荧光猝灭不同组分的作用。 强光(约 1500μmol photons m^(-2) s^(-1))照射叶片使F_0、F_V/F_M和q_(E—fast)降低.q_(E—slow)和q_E增高。NH_4Cl处理使 F_V/F_M降低的幅度和q_E提高的幅度都增加。DTT处理使q_E水平和q_(E—slow)增加的幅度降低,而F_0和稳态荧光水平增加,强光下降低了的F_V/F_M在弱光下不易恢复。NaF处理对这些荧光参数都没有明显的影响。

Using a Hansatech ModulatedFluorometer (MK Ⅱ) we observed thechanges in main fluoreesence parame-ters such as initial fluoreseence F_0, ra-tio of variable fluoreseence to maximalfluoreseence F_v /F_M, and fast compo-nent q_(E-fast) and slow component q_(E-slow) ofnon-photochemical flureseence quench-ing q_E in sweet viburnum leaves duringphotoinhibition of photosynthesis underintense light and successive recoveryunder weak light in order to explore therelative roles of the different compo-nents of q_E in protection against photo-inhibition damage. Illumination with intense light ofabout 1500 umol m^(-2)s^(-1) caused de-creascs in F_0, F_V/F_M and q_(E-fast), andincreases in q_(E-slow) and q_E (from Fig. 1to Fig. 5). NH_4C1 treatment extendedthe extents of both q_(E-slow) increase andF_V/F_M, decrease under intense light(Fig. 1, 2). DTT treatment led to de-creased q_E and deminished extent of0_(E-slow) increase, increased levels of F_0and steady state fluorescence, and slowrecovery under weak light of decreasedF_V/F_M after intense light (Fig. 3, 4).NaF treatment had no significant effecton these fluorescence parameters (Fig.5). The results indicate that of non-photochemical fluorescence quenchingthe slow component related to zeaxan-thin--dependent radiationless energy dis-sipation has a more important role thanthe fast component related to \pH-de-pendent radiationless energy dissipa-tion, but the intermediate componentrelated to state transition of light-har-vesting chlorophyll protein complex ofphotosystem Ⅱ has no role in the pro-tection against photoinhibitory damageof photosynthetic apparatus.