Response of <i>Nostoc flagelliforme cell</i> to Hyperthermia Stress

Abstract

The effects of hyperthermia stress was studied in a terrestrial, drought-tolerant alga, Nostoc flagelliforme. The BG11 culture medium were used to culture Nostoc flagelliforme cell at different temperature conditions: 25°C, 35°C,45°Cand 55°C. The physiological and biochemical character of Nostoc flagelliforme cell, such as electrolyte leakage, the activities of superoxide dismutase(SOD), the content of malondialdehyde(MDA), proline(Pro), soluble protein and trehalose were tested after 8h, 12h, 16h and 24h treatment under 40μmol/m2/s. The results showed that: electrolyte leakage and malondialdehyde contents in Nostoc flagelliforme cell were higher under high temperature stress than those in the control group during high temperature stress. In the meanwhile SOD activity increased slightly under the high temperature stress, but were lower afterwards. The contents of Pro, soluble protein and trehalose increased under the moderately high-temperature stress, while declined under extremely high-temperature(55°C) stress.Therefore, it is proposed that the Nostoc flagelliforme cell had a certain extent resistance ability to the high-temperature, the osmotic adjustment function was stimulated, and the SOD activity was improved under certain high-temperature stress, but the Nostoc flagelliforme cell were damaged badly under extremely high-temperature(55°C) stress.