Steyn W J, Wand S J E, Holcroft D M, Jacobs G
Department of Horticultural Science, University of Stellenbosch, Private BagXI, 7602 Matieland, South Africa.
Department of Horticulture, Michigan State University, East Lansing, MI 48824-1325, USA.
New Phytol. 2002 Sep;155(3):349-361. doi: 10.1046/j.1469-8137.2002.00482.x.
The function of anthocyanins in green, vegetative tissues has always been a contentious issue. Here we evaluate their proposed photoprotective function since recent findings have shown that anthocyanins reduce photoinhibition and photobleaching of chlorophyll under light stress conditions. Anthocyanins generally accumulate in peripheral tissues exposed to high irradiance, although there are some exceptions (e.g. accumulation in abaxial leaf tissues and in obligatory shade plants) and accumulation is usually transient. Anthocyanin accumulation requires light and generally coincides with periods of high excitation pressure and increased potential for photo-oxidative damage due to an imbalance between light capture, CO assimilation and carbohydrate utilization (e.g. greening of developing tissues, senescence and adverse environmental conditions). Light attenuation by anthocyanin may help to re-establish this balance and so reduce the risk of photo-oxidative damage. Although it has been suggested that anthocyanins may act as antioxidants, the association between anthocyanins and oxidative stress appears to relate to the ability of anthocyanins to reduce excitation pressure and, hence, the potential for oxidative damage. The various aspects of anthocyanin induction and pigmentation presented here are compatible with, and support, the proposed general role of anthocyanins as photoprotective light screens in vegetative tissues.
花青素在绿色营养组织中的功能一直是个有争议的问题。在此，我们评估它们所提出的光保护功能，因为最近的研究结果表明，花青素在光胁迫条件下可减少叶绿素的光抑制和光漂白。花青素通常积累在暴露于高辐照度的外周组织中，不过也有一些例外情况（例如在叶片背面组织和专性阴生植物中的积累），并且积累通常是短暂的。花青素的积累需要光照，并且通常与高激发压力时期以及由于光捕获、CO同化和碳水化合物利用之间的不平衡（例如发育中组织的变绿、衰老和不利的环境条件）而导致的光氧化损伤可能性增加相吻合。花青素引起的光衰减可能有助于重新建立这种平衡，从而降低光氧化损伤的风险。尽管有人提出花青素可能作为抗氧化剂起作用，但花青素与氧化应激之间的关联似乎与花青素降低激发压力的能力有关，因此也与氧化损伤的可能性有关。这里介绍的花青素诱导和色素沉着的各个方面与花青素作为营养组织中的光保护光屏的一般作用的提议相符，并提供了支持。
