南极衣藻对黑暗和低温的适应与恢复

Survival and Recovery of Antarctic Chlamydomonas sp.from Darkness and Low Temperature

作为南极海区重要的初级生产者和藻华物种,南极冰藻生长过程中必须忍受长期的黑暗和寒冷。为探讨南极冰藻对黑暗和低温的适应及恢复能力,选择南极冰藻重要物种——衣藻为对象,研究低温和黑暗对其生长、运动状态、叶绿素a含量、颗粒有机碳含量以及光量子收益的影响。结果表明,低温和黑暗均暂时抑制了衣藻细胞的生长和叶绿素浓度,降低了细胞的运动速率,但是衣藻细胞的光合作用能力和颗粒有机碳含量保持稳定。低温和黑暗的协同作用对衣藻生长的影响最显著,但细胞的Fv/Fm及POC含量不受影响。一旦恢复适宜温度和光照,衣藻迅速恢复生长,细胞游动再次活跃,生物量和光合作用效率提高。"内稳态"策略保证南极冰藻具有高度的适应和恢复能力,从而度过南极海区漫长的黑暗和寒冷等极限条件。

The ice algae are considered as one of important primary producers and bloom species in the Antarctic sea.It must subject to prolonged darkness and freezing temperature in the austral winter.We examined the response of growth,swimming,chlorophyll a,POC and maximum quantum yield of Chlamydomonas sp.-dominated ice algae assemblages to prolonged periods of darkness and freezing in this paper.The research showed that low temperature and darkness decreased the growth and biomass of ice algae,while photosynthetic capacity and POC of the alga were not affected.The combined effects of darkness and freezing significantly affected the growth,swimming and chlorophyll a,however,insignificantly influenced the POC and Fv/Fm.The alga quickly resumed growth and swimming upon returning to optimal irradiance and temperature,which also increased the Fv/Fm of PSII in ice algae.Taken together,homeostasis provided ice algae the abilities to survive and initiate growth quickly after freezing and darkness,and partly explained its repeated dominance in the South Sea.