Exposed red (anthocyanic) leaves of Quercus coccifera display shade characteristics
Exposed red (anthocyanic) leaves of Quercus coccifera display shade characteristics
复制标题
DOI：
10.1071/fp02226
复制
发表时间：
2003-01-01
影响因子：
3
通讯作者：
Drinia, A
中科院分区：
文献类型：
--
作者：
Manetas, Y;Petropoulou, Y;Drinia, A
由于花青素的存在，一些植物的幼叶会暂时呈红色，成熟后花青素就会消失。我们研究了这样的假设：花青素引起的光衰减可能导致红叶光合机制的遮荫适应。我们利用了栎树暴露的幼叶花青素水平的种内差异。因此，比较了同一年龄的幼绿叶和红叶的光合和光保护特性，这些幼叶是从占据相同栖息地的相应表型中取样的。红叶表现出多种遮光特性，如叶片较薄、叶绿素 a/b 比率较低以及叶黄素循环成分和 β-胡萝卜素水平较低。此外，虽然两种叶子的叶绿素面积水平相同，但这些色素被排除在表皮下花青素细胞层之外，导致有效叶肉厚度进一步减少，叶绿素密度增加。因此，红叶具有较高的绝对叶绿素荧光信号。尽管有这些明显的遮荫特征，红叶在温和的实验室条件下不太容易受到光抑制，并且在田间黎明前表现出稍微但显着更高的 PS II 光化学效率。在两种表型的成熟绿叶中，所有上述测量参数均未发现差异。结果证实了光适应假说，并且也与花青素的光保护功能相一致。
Young leaves in some plants are transiently red due to the presence of anthocyanins, which disappear upon maturation. We investigated the hypothesis that light attenuation by anthocyanins may lead to a shade acclimation of the photosynthetic machinery in red leaves. We took advantage of the intra-species variation in anthocyanin levels of young, exposed leaves of Quercus coccifera. Thus, photosynthetic and photoprotective characteristics were compared in young green and red leaves of the same age, sampled from the corresponding phenotypes occupying the same habitat. Red leaves displayed several shade attributes like thinner laminae, lower Chl a/b ratios and lower levels of the xanthophyll cycle components and beta-carotene. In addition, although both leaf kinds had the same area based levels of chlorophylls, these pigments were excluded from the sub-epidermic anthocyanic cell layers, leading to a further reduction of effective mesophyll thickness and an increase in chlorophyll density. Accordingly, red leaves had higher absolute chlorophyll fluorescence signals. In spite of these apparent shade characters, red leaves were less prone to photoinhibition under mild laboratory conditions and displayed slightly but significantly higher PS II photochemical efficiencies at pre-dawn in the field. No differences in all the above measured parameters were found in mature green leaves of the two phenotypes. The results confirm the light acclimation hypothesis and are also compatible with a photoprotective function of anthocyanins.