Photoprotective role of rhodoxanthin during cold acclimation in Cryptomeria japonica
Photoprotective role of rhodoxanthin during cold acclimation in Cryptomeria japonica
复制标题
DOI：
10.1046/j.1365-3040.2003.01008.x
复制
发表时间：
2003-05-01
影响因子：
7.3
通讯作者：
Mukai, Y
中科院分区：
文献类型：
--
作者：
Han, Q;Shinohara, K;Mukai, Y
研究的作用，在长期适应低温，我们监测的色素组成，光合作用，叶绿素荧光和水平的核酮糖-1，5-二磷酸羧化酶/加氧酶（Rubisco）的野生型和突变形式的柳杉针叶的季节性变化。在冬季，紫紫红质积累在野生型植物的阳光照射的针叶，但不是在突变体。两种植物的叶绿素含量在冬季均呈下降趋势。相反，在这两种情况下，叶黄素循环池的水平增加。在冬季的突变体的池的水平是野生型的两倍，在叶绿素的基础上，即使在两者的水平在夏季是相似的。如玉米黄质（Z）和花药黄质（A）的持续升高水平所表明的，紫松果黄素的合成可能由光抑制条件触发。在野生型和突变体中，固定CO2的量子效率（phi），光合能力，光系统II（PSII）的光化学效率，光化学猝灭和Rubisco水平在夏季相似。然而，所有这些值的野生型高于那些在冬季的突变体。在冬季，突变体的非光化学猝灭（NPQ）迅速增加，即使在弱光条件下，由于高持续水平的Z和A。相比之下，在野生型中，Z经由A转化为紫紫红质阻止了NPQ的快速增加以维持相对高的phi水平。这些结果表明，紫紫红质可能在长期适应寒冷中发挥重要的光保护作用。相对于叶黄素循环池水平的紫球藻黄质的量的动态调节可能起作用以维持光吸收、光合作用和由于冬季过量吸收的光而引起的能量的热耗散之间的适当平衡。
To examine the role of rhodoxanthin in long-term acclimation to low temperatures, we monitored seasonal changes in pigment composition, photosynthesis, chlorophyll fluorescence and the level of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in needles of wild-type and mutant forms of Cryptomeria japonica. In winter, rhodoxanthin accumulated in sun-exposed needles of wild-type plants, but not in those of the mutant. The level of chlorophyll decreased in both types of plant in winter. In contrast, the level of the xanthophyll cycle pool increased in both cases. The level of the pool in the mutant was twice that in the wild type in winter, on a Chl basis, even though the levels in both were similar in summer. The synthesis of rhodoxanthin might be triggered by photo-inhibitory conditions, as suggested by the sustained elevated levels of zeaxanthin (Z) and antheraxanthin (A). In the wild type and the mutant, the quantum yield of CO2 fixation (phi), the photosynthetic capacity, the photochemical efficiency of photosystem II (PSII), the photochemical quenching and the level of Rubisco in summer were similar. However, all these values for the wild type were higher than those for the mutant in winter. The non-photochemical quenching (NPQ) in the mutant in winter increased rapidly even under low light conditions due to the high sustained levels of Z and A. In contrast, in the wild type, the conversion of Z via A to rhodoxanthin prevented the rapid increase in NPQ to maintain the relatively high level of phi. These findings suggest that rhodoxanthin might play an important photoprotective role in long-term acclimation to cold. The dynamic regulation of the amount of rhodoxanthin relative to the level of the xanthophyll cycle pool might act to maintain an appropriate balance between light absorption, photosynthesis and the thermal dissipation of energy due to excess absorbed light in winter.