北方白菜型冬油菜的膜脂脂肪酸组分和ATPase活性对温度的响应

为了解北方白菜型冬油菜膜脂脂肪酸和ATPase活性与抗寒性的关系,以抗寒性强的冬油菜品种陇油7号和抗寒性弱的品种天油2号为材料,研究了不同温度处理(25°C、10°C、2°C、–5°C)后叶片和根系膜脂脂肪酸组分和ATPase酶活性的变化。结果表明,低温胁迫下2个冬油菜品种叶片和根系膜脂脂肪酸组分相同,叶片中不饱和脂肪酸以亚麻酸为主,根系不饱和脂肪酸以亚油酸为主。随处理温度的降低,2个冬油菜品种叶片不饱和脂肪酸含量呈先降低(10°C,2°C)后增加(–5°C)的趋势;陇油7号根中不饱和脂肪酸含量逐步增加,天油2号则逐步降低;在低温条件下(2°C,–5°C),陇油7号膜脂U/S比值、IUFA值高于天油2号;ATPase活性表现为陇油7号逐渐高于天油2号。说明2个冬油菜品种的膜脂在低温响应上存在一定差异,低温下不饱和脂肪酸含量和ATPase活性的提高是强抗寒冬油菜品种在北方旱寒区严酷环境条件下能安全越冬的重要原因。

Response of Membrane Fatty Acid Composition and ATPase Activity in Brassica rapa L. to Temperature in North China

Brassica rapa L. cultivars Longyou 7 (cold tolerant) and Tianyou 2 (cold sensitive) were used to investigate the variations of membrane fatty acid composition and ATPase activity at the temperatures of 25°C, 10°C, 2°C, and –5°C. There was the same membrane fatty acid composition in leaf and root of two cultivars under temperature stresses, with linolenic acid as the main component of unsaturated fatty acid in leaf, but linoleic acid in root. With decrease of treatment temperatures, the content of unsaturated fatty acid in leaf initially decreased at 10°Cand 2°C, then increased at –5°C.The content of unsaturated fatty acid rose up gradually in root of Longyou 7, but reduced in Tianyou 2. At low temperature(2°C, –5°C), the ratio of U/S and IUFA in Longyou 7 were significantly higher than those in Tianyou 2.The activity of ATPase was gradually increased in Longyou 7 than in Tianyou 2. It suggested there are differences in membrane lipids in response to temperature for two winter rapeseed cultivars, the increase of unsaturated fatty acid content and ATPase activity is the main cause sustaining winter rapeseed cultivars to overwinter.