作　　者： ; ; ; ; ; ;

机构地区： 北京林业大学生物科学与技术学院林木花卉遗传育种教育部重点实验室

出　　处： 《植物生理与分子生物学学报》 2005年第1期34-40,共7页

摘　　要： 对-20℃低温锻炼及脱锻炼过程中甜杨 (Populus suaveolens)幼苗的G6PDH、SOD和POD 活性、MDA含量和半致死温度(LT50)进行了测 定和分析。结果发现,低温锻炼在一定程度上提 高了幼苗6-磷酸葡萄糖脱氢酶(G6PDH)、SOD和 POD活性,降低了MDA含量和幼苗半致死温度 (LT50)。另外,将幼苗放回常温(脱锻炼)2 d能引 起幼苗的G6PDH、SOD和POD活性的显著下降, 并使LT50和MDA含量的迅速回升。结果表明,低 温锻炼中G6PDH活性的增加有助于SOD和POD活 性的提高,进而对幼苗的LT50和MDA含量的降低 有明显的促进作用,G6PDH可能参与了SOD和 POD活性的调节和抗冻性的低温诱导。 To explore the role of glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) in the enhancement of freezing resistance induced by freezing acclimation, G6PDH was purified from the leaves of 8-week-old Populus suaveolens cuttings. The G6PDH activity in the absence or the presence of reduced dithiothreitol (DTTred) were determined, and the changes in superoxide dismutase (SOD), peroxides (POD) and cytosolic G6PDH activities, malondial-dehyde (MDA) content as well as freezing resistance (expressed as LT50) of P. suaveolens cuttings during freezing acclimation at -20℃ were investigated. The results showed that the purified G6PDH was probably located in the cytosol of P. suaveolens. Freezing acclimation increased the activities of SOD, POD and cytosolic G6PDH, and decreased the MDA content and LT50 of cuttings, while 2 d of de-acclimation at 25℃ resulted in a decrease in SOD, POD and cytosolic G6PDH activities, and caused an increase in MDA content and LT50. The change in cytosolic G6PDH activity was found to be closely correlated to the levels of SOD, POD and MDA, and to the degree of freezing resistance of cuttings during freezing acclimation. It is suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation is related to the distinct increase in cytosolic G6PDH activity, which may be involved in the activation of SOD and POD, and the induction of freezing resistance of cuttings.

关 键 词： 甜杨 低温锻炼 抗冻性 半致死温度 磷酸葡萄糖脱氢酶

领　　域： [生物学]