Comparison of the photosynthetic characteristics of two Isochrysis galbana strains under high light
Comparison of the photosynthetic characteristics of two Isochrysis galbana strains under high light
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DOI：
10.1515/bot-2014-0056
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发表时间：
2014-12
期刊：
影响因子：
2.2
通讯作者：
Litao Zhang;Ling Li;Jianguo Liu
中科院分区：
文献类型：
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作者：
Litao Zhang;Ling Li;Jianguo Liu
摘要通过比较高光下海洋微藻等chrysis galbana菌株IOAC724S和IOAC683S的光合特性，探讨了微藻等chrysis galbana的光保护机制。IOAC724S和IOAC683S的rDNA ITS区域在Neighbor-Joining树中紧密聚集，表明两个品系在遗传上非常相似。调节光系统能量耗散（NPQ）和PSI循环电子流动（CEF-I）可以保护光合机构免受光损伤。强光下，IOAC724S和IOAC683S的NPQ和cef - 1无显著差异。两株NPQ均很低，cef - 1维持在较高水平。说明NPQ的强度不足以耗散多余的激发能，cef - 1可能起到保护光合器官免受光损伤的作用。光合线性电子流较低，但PSII内的替代电子流（AEF-II）在IOAC724S中显著高于IOAC683S。IOAC724S中较高的AEF-II有效地去除了多余的激发能，从而保护了光合机构，这可以从PSII不受调节的能量耗散的量子产率值和IOAC724S中较低的过氧化氢含量中看出。
Abstract The photoprotection mechanisms in the marine microalga Isochrysis galbana were examined by comparing the photosynthetic characteristics in two I. galbana strains IOAC724S and IOAC683S under high light. The rDNA ITS regions of IOAC724S and IOAC683S were closely clustered in the Neighbor-Joining tree, suggesting that the two strains are very similar to each other genetically. Regulated energy dissipation in photosystem (PS) II (NPQ) and cyclic electron flow with PSI (CEF-I) can protect the photosynthetic apparatus against photodamage. There were no significant differences in NPQ and CEF-I between IOAC724S and IOAC683S under high light. In both strains, NPQ was very low, and CEF-I was maintained at a high level. This suggested that NPQ was not strong enough to dissipate the excess excitation energy, and CEF-I might protect the photosynthetic apparatus against photodamage in I. galbana. Photosynthetic linear electron flow was lower, but the alternative electron flow within PSII (AEF-II) was significantly higher in IOAC724S than in IOAC683S. The higher AEF-II in IOAC724S efficiently removed excess excitation energy, thereby, protecting the photosynthetic apparatus, as indicated by the lower value of quantum yield of the nonregulated energy dissipation of PSII and the lower content of hydrogen peroxide in IOAC724S.