The photoprotective role of epidermal anthocyanins and surface pubescence in young leaves of grapevine (Vitis vinifera)
The photoprotective role of epidermal anthocyanins and surface pubescence in young leaves of grapevine (Vitis vinifera)
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DOI：
10.1093/aob/mcl097
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发表时间：
2006-07-01
期刊：
影响因子：
4.2
通讯作者：
Karabourniotis, George
中科院分区：
文献类型：
--
作者：
Liakopoulos, Georgios;Nikolopoulos, Dimosthenis;Karabourniotis, George
背景和目的 根据品种的不同，葡萄幼叶表面可能是无毛绿色（“Soultanina”）或短暂具有花青素（“Siriki”）或柔毛（“Athiri”）。测试了花青素和柔毛作为光屏障对相应叶片提供光保护优势的假设，并评估了其作用的大小。方法在田间条件下对三个品种春季的幼叶进行了测量。测量光合气体交换和体内叶绿素荧光。通过 HPLC 分析光合色素和光保护色素。 主要结果 与无毛绿叶相比，花青素叶和短柔毛叶均具有更高的暗适应 PSII 光化学效率和净光合作用。在具有花青素或柔毛的叶子中，叶黄素循环组分与总叶绿素的比率以及叶黄素循环的中午脱环氧化状态比无毛的绿色叶子小得多。这些差异在柔毛叶子中更为明显，可能表明毛状体在减少光胁迫方面比表皮中的花青素更有效。 结论 光屏，尤其是柔毛形式的光屏，降低了光抑制的风险，同时允许叶子保持较小的叶黄素循环成分含量，并且较少依赖叶黄素循环能量耗散。这种光保护特征的组合，即减少光合装置的光子通量和降低叶黄素循环利用率，在应激条件下可能特别有利。
Background and Aims Depending on cultivar, surfaces of young leaves of Vitis vinifera may be glabrous-green ('Soultanina') or transiently have anthocyanins ('Siriki') or pubescence ('Athiri'). A test is made of the hypothesis that anthocyanins and pubescence act as light screens affording a photoprotective advantage to the corresponding leaves, and an assessment is made of the magnitude of their effect.Methods Measurements were made on young leaves of the three cultivars in spring under field conditions. Photosynthetic gas-exchange and in vivo chlorophyll fluorescence were measured. Photosynthetic and photoprotective pigments were analysed by HPLC.Key Results Compared with glabrous-green leaves, both anthocyanic and pubescent leaves had greater dark-adapted PSII photochemical efficiency and net photosynthesis. In leaves possessing either anthocyanins or pubescence, the ratio of xanthophyll cycle components to total chlorophyll, and mid-day de-epoxidation state of the xanthophyll cycle were considerably smaller, than in glabrous-green leaves. These differences were more evident in pubescent leaves, probably indicating that trichomes were more effective in decreasing light stress than anthocyanins in the epidermis.Conclusions Light screens, especially in the form of pubescence, decrease the risk of photoinhibition whilst allowing leaves to maintain a smaller content of xanthophyll cycle components and depend less on xanthophyll cycle energy dissipation. This combination of photoprotective features, i.e. decreased photon flux to the photosynthetic apparatus and lower xanthophyll cycle utilization rates may be particularly advantageous under stressful conditions.