Häder Donat-P, Richter Peter R, Villafañe Virginia E, Helbling E Walter
Neue Str. 9, 91096 Möhrendorf, Germany.
Friedrich-Alexander Universität, Department Biologie, Lehrstuhl für Zellbiologie, AG für Gravitationsbiologie, Staudtstr. 5, 90158 Erlangen, Germany.
J Photochem Photobiol B. 2014 Sep 5;138:273-81. doi: 10.1016/j.jphotobiol.2014.05.020. Epub 2014 Jun 17.
In the wake of global climate change, phytoplankton productivity and species composition is expected to change due to altered external conditions such as temperature, nutrient accessibility, pH and exposure to solar visible (PAR) and ultraviolet radiation (UVR). The previous light history is also of importance for the performance of phytoplankton cells. In order to assess the combined impacts of UVR and temperature on the dinoflagellate Gymnodinium chlorophorum we analyzed the effective photochemical quantum yield (Y), relative electron transport rate vs. irradiance curves (rETR vs. I), percentage of motile cells and swimming velocity. Cells were grown at three different temperatures (15, 20 and 25 °C) and two PAR intensities: low light (LL, 100 μmol photons m(-2) s(-1)) and high light (HL, 250 μmol photons m(-2) s(-1)). Pre-acclimated cells were then exposed to either PAR only (P), PAR+UV-A (PA) or PAR+UV-A+UV-B (PAB) radiation at two different irradiances, followed by a recovery period in darkness. The Y decreased during exposure, being least inhibited in P and most in PAB treatments. Inhibition was higher and recovery slower in LL-grown cells than in HL-grown cells at 15° and 20 °C, but the opposite occurred at 25 °C, when exposed to high irradiances. Maximal values of rETR were determined at t0 as compared to the different (before and after exposure) radiation treatments. The effects of temperature and UVR on rETR were antagonistic in LL-grown cells (i.e., less UVR inhibition at higher temperature), while it was synergistic in HL cells. Swimming velocity and percentage of motile cells were not affected at all tested temperatures and exposure regimes, independent of the light history. Our results indicate that, depending on the previous light history, increased temperature and UVR as predicted under climate change conditions, can have different interactions thus conditioning the photosynthetic response of G. chlorophorum.
在全球气候变化的背景下，由于诸如温度、养分可利用性、pH值以及暴露于太阳可见光（PAR）和紫外线辐射（UVR）等外部条件的改变，浮游植物的生产力和物种组成预计将会发生变化。先前的光照历史对浮游植物细胞的表现也很重要。为了评估UVR和温度对裸甲藻（Gymnodinium chlorophorum）的综合影响，我们分析了有效光化学量子产率（Y）、相对电子传递速率与辐照度曲线（rETR与I）、活动细胞百分比和游动速度。细胞在三种不同温度（15、20和25°C）和两种PAR强度下培养：低光（LL，100 μmol光子 m(-2) s(-1)）和高光（HL，250 μmol光子 m(-2) s(-1)）。然后，预先适应的细胞在两种不同辐照度下暴露于仅PAR（P）、PAR+UV-A（PA）或PAR+UV-A+UV-B（PAB）辐射，随后在黑暗中恢复一段时间。暴露期间Y下降，在P处理中抑制最小，在PAB处理中抑制最大。在15°和20°C时，LL培养的细胞比HL培养的细胞抑制更高且恢复更慢，但在25°C暴露于高辐照度时情况相反。与不同的（暴露前后）辐射处理相比，在t0时确定rETR的最大值。温度和UVR对rETR的影响在LL培养的细胞中是拮抗的（即，在较高温度下UVR抑制较小），而在HL细胞中是协同的。在所有测试温度和暴露条件下，游动速度和活动细胞百分比均不受影响，与光照历史无关。我们的结果表明，根据先前的光照历史，气候变化条件下预测的温度升高和UVR增加可能具有不同的相互作用，从而影响裸甲藻的光合反应。
Zotero 插件