Sensitivity of Laminariales zoospores from Helgoland (North Sea) to ultraviolet and photosynthetically active radiation: implications for depth distribution and seasonal reproduction
Sensitivity of Laminariales zoospores from Helgoland (North Sea) to ultraviolet and photosynthetically active radiation: implications for depth distribution and seasonal reproduction
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赫尔戈兰岛（北海）海带目游动孢子对紫外线和光合有效辐射的敏感性：对深度分布和季节性繁殖的影响
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Ansgar Gruber
中科院分区：
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作者：
M. Roleda;C. Wiencke;D. Hanelt;W. Poll;Ansgar Gruber
黑尔戈兰(北海)海带种类的深度分布以海带发生在上潮下带为特征，而L则不同。甘蔗和L。中、下胸下区以金丝桃亚科为主。海带在夏季是可育的，而其他两种在秋/冬都是可育的。为测定指甲游动孢子繁殖体光敏感度，L。甘蔗和L。在实验室条件下，对金丝桃进行了不同时间的光合有效辐射(PAR；400-700 nm)、PAR+UVA辐射(UVAR；320-400 nm)和PAR+UVAR+UVB辐射(UVBR；280-320 nm)的照射。测定了辐照后PSII的最适量子效率和DNA损伤。随后，在暗白光下培养2、3d后，测定其光合作用效率的恢复、DNA损伤修复以及发芽率。所有植物的光合作用效率在20 mmol光子m~(-2)S~(-1)PAR时就已经受到光抑制，而紫外线辐射对光抑制有显著的附加作用。PAR+UVA+UVB照射4h以上和PAR+UVA照射8h以上，所有菌种的PSII功能均有恢复，但孢子未见恢复。以环丁烷嘧啶二聚体(CPDS)表示的UVB对DNA的损伤量随暴露时间的延长而增加，以潮下L的孢子损伤最大。相对其他两种的金丝桃属。在弱白光下，所有物种在2d后都能观察到表明DNA损伤修复的CPD显着去除，尤其是潮下上层L的孢子。数字。因此，有效的DNA损伤修复和PSII损伤的恢复有助于萌发的成功，而对暴露于UVBR 16h的孢子则不起作用。L游动孢子悬浮液的紫外吸收。洋地黄既基于游动孢子本身的吸收，也基于介质中的渗出物。相比之下，L对游动孢子悬浮液的吸收。甘蔗和L。金丝桃主要基于介质中渗出物的吸收。研究表明，游动孢子对UVR的敏感性与游动孢子的季节产生量有关，也与大型孢子体的垂直分布格局有关。
Depth distribution of kelp species in Helgoland (North Sea) is characterized by occurrence of Laminaria digitata in the upper sublittoral, whereas L . saccharina and L . hyperborea dominate the mid and lower sublittoral region. Laminaria digitata is fertile in summer whereas both other species are fertile in autumn/winter. To determine the light sensitivity of the propagules, zoospores of L. digitata , L . saccharina and L . hyperborea were exposed in the laboratory to different exposure times of photosynthetically active radiation (PAR; 400‐700 nm), PAR + UVA radiation (UVAR; 320‐400 nm) and PAR + UVAR + UVB radiation (UVBR; 280‐320 nm). Optimum quantum yield of PSII and DNA damage were measured after exposure. Subsequently, recovery of photosynthetic efficiency and DNA damage repair, as well as germination rate were measured after 2 and 3 d cultivation in dim white light. Photosynthetic efficiency of all species was photoinhibited already at 20 m mol photons m - 2 s - 1 PAR, whereas UV radiation (UVR) had a significant additional effect on photoinhibition. Recovery of the PSII function was observed in all species but not in spores exposed to irradiation longer than 4 h of PAR + UVA + UVB and 8 h of PAR + UVA. The amount of UVB-induced DNA damage measured as cyclobutane‐pyrimidine dimers (CPDs) increased with exposure time and highest damage was detected in the spores of lower subtidal L . hyperborea relative to the other two species. Significant removal of CPDs indicating repair of DNA damage was observed in all species after 2 d in low white light especially in the spores of upper subtidal L . digitata . Therefore, efficient DNA damage repair and recovery of PSII damage contributed to the germination success but not in spores exposed to 16 h of UVBR. UV absorption of zoospore suspension in L . digitata is based both on the absorption by the zoospores itself as well as by exudates in the medium. In contrast, the absorption of the zoospore suspension in L . saccharina and L . hyperborea is based predominantly on the absorption by the exudates in the medium. This study indicates that UVR sensitivity of zoospores is related to the seasonal zoospore production as well as the vertical distribution pattern of the large sporophytes.