Growth form defines physiological photoprotective capacity in intertidal benthic diatoms
Growth form defines physiological photoprotective capacity in intertidal benthic diatoms
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DOI：
10.1038/ismej.2014.105
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发表时间：
2015-01-01
期刊：
影响因子：
11
通讯作者：
Lavaud, Johann
中科院分区：
文献类型：
--
作者：
Barnett, Alexandre;Meleder, Vona;Lavaud, Johann
在潮间带海洋沉积物中，其特征是快速波动和经常极端的光照条件，初级生产往往是由硅藻主导。对沉积物中15种底栖硅藻的生理特征进行了比较分析，这些硅藻分属于4种主要的形态生长型（epipelon，EPL）、运动型（motile epipsammon，EPM-M）、非运动型（non-motile epipsammon，EPM-NM）和典型浮游生物（tychoplankton，TYCHO）。我们的分析揭示了生长形式和光保护能力之间的明确关系，并确定了快速调节生理光保护性状（即，非光化学猝灭（NPQ）和叶黄素循环（XC））作为定义这些硅藻的功能性光响应的关键性状。EPM-NM和运动型EPL分别显示最高和最低NPQ，EPM-M显示中间值。与EPL一样，TYCHO的NPQ较低，无论它们是在底栖条件下生长还是在水生条件下生长，反映了对弱光环境的适应。因此，我们的研究结果提供了第一个实验证据之间存在的权衡行为（运动）和生理光保护机制（NPQ和XC）在四个主要的潮间带底栖硅藻生长形式使用unialgae文化。值得注意的是，虽然运动仅限于针羽状硅藻分支，针羽状物种，它采用了非运动epipsammic或tychoacetonic生活方式，显示这些生长形式的典型的生理光保护反应。这一观察结果强调了生长形式的重要性，而不是系统发育的相关性作为塑造底栖硅藻的生理光保护能力的主要决定因素。
In intertidal marine sediments, characterized by rapidly fluctuating and often extreme light conditions, primary production is frequently dominated by diatoms. We performed a comparative analysis of photophysiological traits in 15 marine benthic diatom species belonging to the four major morphological growth forms (epipelon (EPL), motile epipsammon (EPM-M) and non-motile epipsammon (EPM-NM) and tychoplankton (TYCHO)) found in these sediments. Our analyses revealed a clear relationship between growth form and photoprotective capacity, and identified fast regulatory physiological photoprotective traits (that is, non-photochemical quenching (NPQ) and the xanthophyll cycle (XC)) as key traits defining the functional light response of these diatoms. EPM-NM and motile EPL showed the highest and lowest NPQ, respectively, with EPM-M showing intermediate values. Like EPL, TYCHO had low NPQ, irrespective of whether they were grown in benthic or planktonic conditions, reflecting an adaptation to a low light environment. Our results thus provide the first experimental evidence for the existence of a trade-off between behavioural (motility) and physiological photoprotective mechanisms (NPQ and the XC) in the four major intertidal benthic diatoms growth forms using unialgal cultures. Remarkably, although motility is restricted to the raphid pennate diatom clade, raphid pennate species, which have adopted a non-motile epipsammic or a tychoplanktonic life style, display the physiological photoprotective response typical of these growth forms. This observation underscores the importance of growth form and not phylogenetic relatedness as the prime determinant shaping the physiological photoprotective capacity of benthic diatoms.