外源药剂处理对玉米叶黄素循环与非辐射能量耗散的影响

EFFECT OF EXTERNAL REAGENTS ON THE XANTHOPHYLL CYCLE AND NON-RADIATIVE ENERGY DISSIPATION IN LEAVES OF MAIZE

摘要:

利用AsA、DTT和NADPH溶液处理离体玉米叶片,对其叶黄素循环和非辐射能量耗散都可产生一定的影响。20 mmol/L AsA可促进紫黄质(V)向单环氧玉米黄质(A)至玉米黄质(Z)的转化,NPQ值和Fv/Fm均相应增加,但是生成的Z在强光下(＞650μmol m^-2s^-1)很容易达到饱和。5 mmol/L DTT可明显抑制Z的增加,但对A的影响很小,同时玉米叶片的NPQ值和Fv/Fm均显著下降。0.5 mmol/L NADPH也可抑制玉米叶片中V向Z和A的转化,但是强光可以明显减轻这种作用,而且对应的NPQ值和Fv/Fm均与Z含量同步下降。总体上来看,这三种处理均通过改变玉米叶片中Z和A的含量来影响其非辐射能量耗散,而对总叶黄素库的大小影响很弱。

Abstract:

When detached leaves of maize (Zea mays L.) were treated with AsA, NADPH and DTT solution, the xanthophyll cycle and non-radiative energy dissipation (NRD) all changed correspondingly in certain degree. 20 mmol/L AsA could markedly promote the deepoxidation of violaxanthin (V) to zeaxanthin (Z) via antheraxanthin (A), the non-photochemical quenching (NPQ) value and Fv/Fm both apparently increased, but Z is easily to be saturated under high light (>650 μmol m^-2s^-1). 5 mmol/L DTT inhibited the formation of Z significantly，and slightly affected A content．In the same condition．the NPQ value and Fv/Fm of maize leaves all rapidly decreased．0.5 mmol/L NADPH also inhibited the transformation of V to Z， but this effect was reduced under hight 1ight condition．The corresponding NPQ value and Fv/Fm all decreased following the decrease of Z．In summary，this three kinds of treatments all affected the NRD through changing the contents of Z and A，but not the size of xanthophyll pool．