Mechanisms of drought-induced dissipation of excitation energy in sun- and shade-adapted drought-tolerant mosses studied by fluorescence yield change and global and target analysis of fluorescence decay kinetics
Mechanisms of drought-induced dissipation of excitation energy in sun- and shade-adapted drought-tolerant mosses studied by fluorescence yield change and global and target analysis of fluorescence decay kinetics
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通过荧光产量变化和荧光衰减动力学的全局和目标分析研究耐光和荫蔽耐旱苔藓中干旱引起的激发能量耗散机制
DOI：
10.1007/s11120-017-0465-9
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发表时间：
2017
影响因子：
3.7
通讯作者：
Itoh Shigeru
中科院分区：
文献类型：
--
作者：
Yamakawa Hisanori;van Stokkum Ivo H. M.;Heber Ulrich;Itoh Shigeru
有些苔藓即使在干燥的情况下也能保持绿色并存活很长时间。研究了两种适应对比生态位的耐旱苔藓物种的过量激发能量的耗散机制：同一科的适应荫凉的Rhytidiadelphus squarrosus和适应阳光的Rhytidium rugosumin。 (1) 在潮湿条件下，光诱导的非光化学猝灭 (NPQ) 机制降低了两个物种的光系统 II (PSII) 荧光产量。 NPQ 范围在 R 中较低的照明强度下饱和。 squarrosus，表明 PSII 天线尺寸更大。 (2) 干燥降低了荧光强度，显着降低了 F0 水平，并缩短了两个 R 的总体荧光寿命。 squarrosusandR. rugosum，在室温下。 (3) 77 K 时，干燥强烈降低 PSII 荧光强度。 R 中这种减少幅度较小。 squarrosusthan inR。皱褶。 (4)全局和目标分析表明PSII在干燥条件下有两种不同的能量耗散机制：在适应阳光的R中，能量耗散到PSII核心中干燥形成的强荧光猝灭剂。 rugosum（A 型猝灭）和（5）在阴影适应 R 中的光捕获复合物/PSII 中的适度能量耗散。 squarrosus（B 型淬火）。这两种机制与两种苔藓的不同生态位相一致。
Some mosses stay green and survive long even under desiccation. Dissipation mechanisms of excess excitation energy were studied in two drought-tolerant moss species adapted to contrasting niches: shade-adaptedRhytidiadelphus squarrosusand sun-adaptedRhytidium rugosumin the same family. (1) Under wet conditions, a light-induced nonphotochemical quenching (NPQ) mechanism decreased the yield of photosystem II (PSII) fluorescence in both species. The NPQ extent saturated at a lower illumination intensity inR. squarrosus, suggesting a larger PSII antenna size. (2) Desiccation reduced the fluorescence intensities giving significantly lowerF0levels and shortened the overall fluorescence lifetimes in bothR. squarrosusandR. rugosum, at room temperature. (3) At 77 K, desiccation strongly reduced the PSII fluorescence intensity. This reduction was smaller inR. squarrosusthan inR. rugosum. (4) Global and target analysis indicated two different mechanisms of energy dissipation in PSII under desiccation: the energy dissipation to a desiccation-formed strong fluorescence quencher in the PSII core in sun-adaptedR. rugosum(type-A quenching) and (5) the moderate energy dissipation in the light-harvesting complex/PSII in shade-adaptedR. squarrosus(type-B quenching). The two mechanisms are consistent with the different ecological niches of the two mosses.