Sensitivity of photosystem 2 of Antarctic lichens to high irradiance stress:: Fluorometric study of fruticose (Usnea antarctica) and foliose (Umbilicaria decussata) species
Sensitivity of photosystem 2 of Antarctic lichens to high irradiance stress:: Fluorometric study of fruticose (Usnea antarctica) and foliose (Umbilicaria decussata) species
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DOI：
10.1023/b:phot.0000027513.90599.ad
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发表时间：
2003-01-01
期刊：
影响因子：
2.7
通讯作者：
Hájek, J
中科院分区：
文献类型：
--
作者：
Barták, M;Vráblíková, H;Hájek, J
在实验室条件下，对采集于南极海洋（乔治王岛）的两种地衣进行了过量辐照下光系统2（PS2）的响应研究。在5 ℃下，通过调制荧光计使用叶绿素（Chl）荧光诱导曲线并辅以猝灭机制分析，在完全水合的地衣菌体上测量响应。叶绿素荧光参数[即可变叶绿素荧光与最大叶绿素荧光的比值（Fv/FM）、PS 2光化学反应的量子产率（Phi（2））、猝灭系数]在暴露于高辐照之前和之后多次进行评估，以确定光抑制的程度、快速和缓慢的恢复阶段。强光照（2 000 mumol m（-2）s（-1））引起的光抑制程度较高，尤其是灌木状的松萝（Usneaanarctica）比叶状的石脐（Umbilicariadecussata）地衣高。光抑制的快速恢复期与PS2的调节机制相对应，在U. decussata和Phi（2）比U.光抑制处理后40 min内，抗肿瘤药和F-V/F-M和Phi（2）。随后是一个持续数小时的缓慢阶段，相当于修复和再合成过程。光抑制处理后，非光化学猝灭（NPQ）的恢复速度更快，更明显的U。decussata比U.南极洲NPQ的快恢复（q（E））和慢恢复（q（T+1））组分的恢复率在两种鱼之间存在显著差异。
Two lichen species collected in maritime Antarctica (King George Island) were exposed under laboratory conditions to excess irradiance to evaluate the response of photosystem 2 (PS2). The response was measured on fully hydrated lichen thalli at 5 C by means of a modulated fluorometer using chlorophyll (Chl) fluorescence induction curve supplemented with analysis of quenching mechanisms. Chl fluorescence parameters [i.e. ratio of variable to maximum Chl fluorescence (Fv/FM), quantum yield of PS2 photochemical reactions (Phi(2)), quenching coefficients] were evaluated before and several times after exposition to high irradiance in order to characterise the extent of photoinhibition, fast and slow phase of recovery. Strong irradiance (2 000 mumol m(-2) s(-1)) caused high degree of photoinhibition, particularly higher in fruticose (Usnea antarctica) than in foliose (Umbilicaria decussata) lichen species. Fast phase of recovery from photoinhibition, corresponding to regulatory mechanisms of PS2, was more apparent in U. decussata and Phi(2) than in U. antarctica and F-V/F-M and Phi(2) within 40 min after photoinhibitory treatment. It was followed by a slow phase lasting several hours, corresponding to repair and re-synthesis processes. After photoinhibitory treatment, recovery of non-photochemical quenching (NPQ) was faster and more pronounced in U. decussata than in U. antarctica. Significant differences were found between the two species in the rate of recovery in fast- (q(E)) and slow-recovering (q(T+1)) component of NPQ.