Roleda Michael Y, Campana Gabriela L, Wiencke Christian, Hanelt Dieter, Quartino Maria Liliana, Wulff Angela
Institute for Polar Ecology, Wischhofstraße 1-3, Bldg. 12, D-24148 Kiel, GermanyCONICET, Instituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaSection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, GermanyInstituto Antártico Argentino, Cerrito 1248 (C1010AAZ), CA de Buenos Aires, ArgentinaDepartment of Marine Ecology, Marine Botany, Gothenburg University, Box 461, SE 40530 Gothenburg, Sweden.
J Phycol. 2009 Jun;45(3):600-9. doi: 10.1111/j.1529-8817.2009.00691.x. Epub 2009 Jun 1.
The sensitivity of different life stages of the eulittoral green alga Urospora penicilliformis (Roth) Aresch. to ultraviolet radiation (UVR) was examined in the laboratory. Gametophytic filaments and propagules (zoospores and gametes) released from filaments were separately exposed to different fluence of radiation treatments consisting of PAR (P = 400-700 nm), PAR + ultraviolet A (UVA) (PA, UVA = 320-400 nm), and PAR + UVA + ultraviolet B (UVB) (PAB, UVB = 280-320 nm). Photophysiological indices (ETRmax , Ek , and α) derived from rapid light curves were measured in controls, while photosynthetic efficiency and amount of DNA lesions in terms of cyclobutane pyrimidine dimers (CPDs) were measured after exposure to radiation treatments and after recovery in low PAR; pigments of propagules were quantified after exposure treatment only. The photosynthetic conversion efficiency (α) and photosynthetic capacity (rETRmax ) were higher in gametophytes compared with the propagules. The propagules were slightly more sensitive to UVB-induced DNA damage; however, both life stages of the eulittoral inhabiting turf alga were not severely affected by the negative impacts of UVR. Exposure to a maximum of 8 h UVR caused mild effects on the photochemical efficiency of PSII and induced minimal DNA lesions in both the gametophytes and propagules. Pigment concentrations were not significantly different between PAR-exposed and PAR + UVR-exposed propagules. Our data showed that U. penicilliformis from the Antarctic is rather insensitive to the applied UVR. This amphi-equatorial species possesses different protective mechanisms that can cope with high UVR in cold-temperate waters of both hemispheres and in polar regions under conditions of increasing UVR as a consequence of further reduction of stratospheric ozone.
在实验室中检测了潮间带绿藻丝状硬毛藻（Urospora penicilliformis (Roth) Aresch.）不同生活阶段对紫外线辐射（UVR）的敏感性。将配子体丝状体以及从丝状体释放的繁殖体（游动孢子和配子）分别暴露于不同辐射通量处理下，这些处理包括光合有效辐射（PAR，P = 400 - 700 nm）、PAR + 紫外线A（UVA，UVA = 320 - 400 nm）以及PAR + UVA + 紫外线B（UVB，UVB = 280 - 320 nm）。在对照组中测量从快速光曲线得出的光生理指标（最大电子传递速率ETRmax、光补偿点Ek和光化学效率α），而在辐射处理后以及在低PAR下恢复后测量光合效率和以环丁烷嘧啶二聚体（CPD）表示的DNA损伤量；仅在暴露处理后对繁殖体的色素进行定量。与繁殖体相比，配子体的光合转化效率（α）和光合能力（rETRmax）更高。繁殖体对UVB诱导的DNA损伤稍更敏感；然而，这种潮间带丛生藻类的两个生活阶段均未受到UVR负面影响的严重影响。暴露于最长8小时的UVR对PSII的光化学效率产生轻微影响，并在配子体和繁殖体中诱导出最小程度的DNA损伤。暴露于PAR和暴露于PAR + UVR的繁殖体之间色素浓度没有显著差异。我们的数据表明，来自南极的丝状硬毛藻对所施加的UVR相当不敏感。这种泛赤道物种拥有不同的保护机制，能够在平流层臭氧进一步减少导致UVR增加的条件下，应对南北半球温带冷水域和极地地区的高UVR。
