Tb(Ⅲ)对辣根叶片膜脂脂肪酸构成的影响

EFFECT OF Tb(Ⅲ)ON PLASMA MEMBRANE FATTY ACIDS COMPOSITION IN HORSERADISH LEAVES

以辣根为材料,研究叶面喷洒Tb(Ⅲ)对辣根叶片膜脂脂肪酸构成的影响.结果表明,5mg·l-1和60mg·l-1Tb(Ⅲ)均能增加膜脂饱和脂肪酸的百分含量,而降低不饱和脂肪酸含量,尤其是亚麻酸,但5mg·l-1Tb(Ⅲ)未能改变不饱和度指数,60mg·l-1Tb(Ⅲ)使不饱和度指数显著降低.同时,Tb(Ⅲ)使辣根叶片HRP活性降低,膜脂发生过氧化,表现为MDA含量增加.因此,Tb(Ⅲ)处理下膜脂脂肪酸的变化与Tb(Ⅲ)诱导的自由基升高有关,且在所有脂肪酸中,亚麻酸在稀土对膜脂脂肪酸影响中贡献最大.

Effect of Tb （Ⅲ ） on plasma membrane fatty acids composition in horseradish leaves by foliage spray was investigated in this paper. The results show that there is a increase in the content of saturated fatty acids of plasma membrane in the horseradish leaves treated with 5 mg · l^-1 and 60 mg · l^-1 Tb （Ⅲ ）, and a decrease in the content of unsaturated fatty acids of plasma membrane, especially linolenic acid （ 18： 3） . Moreover, 5 mg· l^-1 Tb（Ⅲ） can not change the index of unsaturated fatty acids （IUFA）, while 60 mg · l^-1 Tb（Ⅲ） makes IUFA decrease. Furthermore, the increase in the content of MDA and decrease in the activity of HRP in horseradish leaves treated with Tb（Ⅲ） are observed. Therefore, we can conclude that the change in plasma membrane fatty acids is related with the increase in the content of free radicals induced by Tb （Ⅲ）. Moreover, 18： 3, is the most important fatty acid contributing to the effect of rare earth on plasma membrane fatty acids amongst all fatty acids.