南极冰藻Chlamydomonas sp.ICE-L的抗盐性

Salt resistance of Antarctic ice microalga Chlamydomonas sp.

以南极冰藻(Chlamydomonassp.)为材料对其抗盐性进行研究,结果表明,冰藻在盐度33下生长良好,在盐度66和99也有较大的生长量,盐度132下也能生存,可以维持原有的生物量,而盐度165对冰藻则是致命的,仅能存活8 d;常温藻(Chlamydomonas monadina)仅能在盐度小于99时生存。由此可以看出,南极藻类较常温藻可抗更高的盐度。同时测定了与盐度变化相关的膜系统变化,与常温藻相比,南极冰藻中的超氧化物歧化酶(SOD)、丙二醛(MDA)和脯氨酸含量较高,而膜透性较低;经盐度99胁迫后,以上4种生化指标都升高。本研究初步结论为,超氧化物歧化酶、丙二醛、脯氨酸和膜透性对南极冰藻的抗盐性研究均有较好的指导意义。这项研究旨为南极冰藻抗盐机理研究提供基础依据。[中国水产科学,2006,13(1):73-78]

Antarctic ice microalgae can survive and thrive in channels or pores with high salinity water in Antarctic ice layer. In this study, Antarctic ice microalga Chlamydomonas sp. ICE-L, isolated from Antarctic sea ice samples collected in 18th Chinese Antarctic expedition during 2001/2002, was used as studied material. The resistance of Chlamydomonas sp. ICE-L to different salinity was determined with mesophilic microalga Chlamydomonas monadina as control, and the results showed that two species of microalgae could both grow normally at salinity 33. Chlamydomonas sp. ICE-L grew slowly at the beginning, but increased quickly after 6 days and got to the maximal growth on the 14th day, when the cell density was 1.8 ×10^7 mL^-1. Mesophilic microalga C. monadina grew quickly, and its exponential growth phase was from the second day to the sixth day of culture, when the change of cell density was slightly. At salinities 66 and 99, the growth curves of ice microalga were alike. After the adaptation of 8 - 10 days in high salinity, Chlamydomonas sp. ICE-L began to grow rapidly, and got to maximal density on the 14th day. For mesophilic microalga C. monadina, the exponential growth phase were from the second day to the 8th day and from the 6th day to the 12th day respectively at salinities 66 and 99, and their maximal density were 1067 mL^-1 and 0.85×10^7 mL^-1 respectively on the 12th day. The density of Chlamydomonas sp. ICE-L almost did not change at salinity 132, maintained at about 5 ×10^7 mL^- 1. However, the salinity 132 was fatal to mesophilic microalga with no livable cell after the 6th day. Both ice and mesophilic microalga could not survive at the salinity of 165, and all cells were bleached and dead on the 8th and the 6th days respectively. This study indicates Antarctic ice microalgae were tested in a wider range of resistance to high salinity. At the same time, some biochemical changes in Chlamydomonas sp. ICE-L related to salinity resistance were also determined. The contents of Superoxide Dismutase （SOD）, Malondialdehyde （MDA） and proline in Antarctic ice microalga were higher than those in mesophilic microalga, while the cell membrane permeability was lower. At high salinity pressure of 99, the contents of SOD, MDA and proline increased, and the same to cell membrane permeability. So the conclusion is that the contents of SOD, MDA, proline and the cell membrane permeability can indicate the salt resistance of Antarctic ice microalga.