High light stress in the kelp Ecklonia cava
High light stress in the kelp Ecklonia cava
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DOI：
10.1016/j.aquabot.2004.01.011
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发表时间：
2004-06-01
期刊：
影响因子：
1.8
通讯作者：
Kawai, H
中科院分区：
文献类型：
--
作者：
Altamirano, M;Murakami, A;Kawai, H
研究了不同发育阶段和生活史阶段的Ecklonia cava（实验室培养的配子体和幼孢子体以及原位收集的老孢子体）对强光胁迫的适应性。利用脉冲幅度调制（PAM）荧光法测定了PSII叶绿素a的最佳量子效率（F-v/F-m）、光合效率（a）和容量（ETRmax）的变化，研究了各阶段的抑制和恢复动力学。经过2小时的高辐照度（500 mumol m（-2）s（-1）PAR），半小叶簇的配子体没有强调，而孢子体发生严重的光抑制（65%），与不同的发展阶段。在老孢子体中，抑制和恢复（昏暗的光线条件下，10 mumol m（-2）s（-1）PAR）动力学比年轻孢子体快，表示从两个时期的对数拟合估计的参数m的值。此外，与年轻孢子体相比，老孢子体的α和ETRmax几乎没有变化。因此，老年孢子体可能发生动态光抑制，而年轻孢子体可能发生慢性光抑制和光损伤。不同发育阶段的形态特征和生理光适应能力的差异可以解释它们对强光敏感性的差异。密集的丛状形态可以自我遮蔽，保护配子体的内细胞免受强光胁迫。具有较高色素含量的老孢子体的薄壁组织结构可能比年轻孢子体的不太复杂的结构提供更多的保护。然而，预处理条件的差异也可以解释这种差异。(C)2004 Elsevier B. V.保留所有权利。
Acclimation to high light stress was studied in different developmental and life-history stages of Ecklonia cava (gametophytes and young sporophytes cultivated in the laboratory and old sporophytes collected in situ). Changes in optimal quantum yield (F-v/F-m), photosynthetic efficiency (a) and capacity (ETRmax), measured by pulse amplitude modulation (PAM) fluorometry of chlorophyll a of PSII, were studied in order to investigate the inhibition and recovery kinetics of each stage. After 2 h in high irradiance (500 mumol m(-2) s(-1) PAR), hemiglobular tufts of gametophytes were not stressed, whereas sporophytes underwent severe photoinhibition (65%), with differences depending on the developmental stage. In old sporophytes, inhibition and recovery (dim light conditions, 10 mumol m(-2) s(-1) PAR) kinetics were faster than in young sporophytes, as denoted the values of the parameter m estimated from the logarithmic fittings of both periods. Furthermore, alpha and ETRmax of old sporophytes hardly changed compared to those of young sporophytes. Therefore, dynamic photoinhibition may occur in old sporophytes, but chronic photoinhibition with photodamage in young ones. Morphological features and physiological light acclimation differences among these stages may explain the differences in sensitivity to high irradiance. Dense tuft-like morphology may self-shade and protect inner cells of gametophytes against high light stress. The parenchymatous structure of old sporophytes with higher pigment contents may offer more protection against high irradiance than the less complex structure of young sporophytes. However, differences in the pre-treatment conditions may also explain this difference. (C) 2004 Elsevier B.V. All rights reserved.