拟南芥叶黄素缺失突变体叶绿素荧光猝灭的特性

The Feature of Chlorophyll Fluorescence Quenching in Xanthophyll-deficient Mutants of Arabidopsis thaliana

研究了 3个叶黄素组分缺失的拟南芥核基因突变体 ,npq1(缺乏玉米黄质Z和单环氧玉米黄质A)、lut2(缺乏lutein)和lut2 npq1(双突变体 ,同时缺Z和lutein) ,及其对照野生型 (WT)在强光诱导下叶绿素荧光猝灭的特性 .与WT相比 ,3个突变体的叶绿素a/b没有明显的差异 ,Fv/Fm 则有不同幅度的增加 ,缺乏lutein的突变体lut2 和lut2 npq1的叶黄素循环库 (V +A +Z)显著增大 .缺乏Z的突变体npq1和lut2 npq1在强光下 ,荧光的非光化学猝灭 (NPQ)的诱导受到明显抑制 ,lut2 的NPQ形成也受到部分抑制 .强光处理 9min后 ,3个突变体和WT的NPQ大小顺序为WT >lut2 >npq1>npq1 lut2 .强光诱导过程中突变体的光化学猝灭 (qP)都小于WT .强光下突变体显示较弱的抗光抑制能力 ,其抗光抑制能力的强弱顺序为 :WT >lut2 >npq1>lut2 npq1.结果表明叶黄素循环不但与NPQ的形成直接相关也与

The chlorophyll fluorescence quenching in leaves of wildtype (WT) and three nuclear mutants of Arabidopsis thaliana including npq(1) ( lutein-replete and violaxanthin deepoxidase-deficient), lut(2) ( lutein-deficient) and lut(2)-npq(1) (double mutant) under high light condition was characterized. There was no obvious difference in ratio of Chl a/b between mutants and wildtype, while F-v/F-m in mutants increased to some extents. The total xanthophyll pool (V + A + Z) increased significantly in lutein-deficient mutants (lut2 and lut(2)-npq(1)). The NPQ induction by high light was markedly inhibited in lut(2)-npq(1) and npq(1), but showed less inhibition in lut2. The trend of NPQ value in mutants and WT exposed to PPFD during high light illumination of 2 000 mumol . m(-2). s(-1) for 1 similar to 9 min was WT > lut(2) > npq(1) > lut(2)-npq(1). qP in all three mutants decreased in comparison with wildtype. Three xanthophyll-dificient mutants exhibited less resistance to photoinhibition than the WT. The sequence of tolerance to photoinhibition was the same as the changes in NPQ among WT and mutants (WT > lut(2) > npq(1) > lut(2)-npq(1)). The results indicated that xanthophyll cycle was related not only directly to NPQ formation, but also to qP.