耐寒与不耐寒玉米生物膜膜脂差热分析研究

DIFFERENTIAL THERMAL ANALYSIS OF THE BIOMEMBRANES OF CHILLING-SENSITIVE AND CHILLING-TOLERANT CORN GENOTYPES

对耐寒与不耐寒玉米进行差热分析表明,耐寒玉米品种相变温度较低,不耐寒品种较高。不耐寒品种膜脂脂肪酸不饱和指数低,耐寒品种则较高,并具有较高的亚油酸<棕榈酸比值。25℃培养的玉米幼苗膜脂脂肪酸含量的变化无明显规律性,品种间亦无明显差异,但经低温处理后,两类品种脂肪酸不饱和度都有增加,与品种的耐寒性也有一定的联系。

Differential thermal analysis(DTA)of a chilling-sensitive corngenotype and a chilling-tolerant genotype showed that the transition tem-perature of the chilling-tolerant corn was lower than that of the chilli-ng-sensitive corn.The weight per cent composition of unsaturated memb-vance fatty acids between the two genotypes appeared to be substantiallydifferent,the indices of unsaturation of the membrane fatty acids of thesensitive genotype being lower than those of the tolerant genotype.Higher linoleic acid:palmitic acid ratios were observed in the sens-itive genotype:No consistency,however,was noticed in the fluctuationsof the membrane fatty acids of the corn seedlings kept at 25℃,and nomarked differences between the varieties were found.After chilling trea-tments,the portion of unsaturated fatty acids increased in both varieties,which seemed to be related to their resistance to cold stress.