低温胁迫对甜菜抗氧化系统的影响

旨在研究低温胁迫对甜菜细胞膜过氧化及抗氧化系统的影响,并为研究其他植物的抗寒性生理机制提供参考依据。以甜菜品种‘KWS9147'为实验材料,采用水培方式栽培,设置了4℃的低温处理(L)和25℃的室温对照(CK),测定低温处理前后甜菜叶片中丙二醛(MDA)含量和抗氧化系统酶活性的变化。结果表明,低温胁迫会对细胞膜造成损害并促使抗氧化系统产生防御作用,甜菜低温胁迫处理1天后与对照组对比,丙二醛(MDA)含量和抗氧化系统酶活性发生了显著的变化,丙二醛(MDA)的含量增加了31.32%,总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)及过氧化氢酶(CAT)活性显著上升,分别上升了10.74%、4倍、2.22倍、32.85%、和2.56倍。综上,甜菜在低温胁迫下抗氧化能力提高,从而清除活性氧自由基(ROS)的积累,减缓细胞膜脂过氧化对细胞造成的伤害。

Effect of Low Temperature Stress on the Antioxidant System of Sugar Beet

The aims of this study are to investigate the effects of low temperature stress on cell membrane peroxidation and antioxidant system in sugar beet, and provide reference for studying physiological mechanism of cold resistance in other plants. Sugar beet variety ‘KWS9147' was selected as the experimental material and cultivated in hydroponic culture. The low temperature (4℃) was used as stress treatment (L) and the room temperature (25℃) was used as control (CK). The changes of malondialdehyde (MDA) content and antioxidant system enzyme activity in sugar beet leaves before and after low temperature treatment were measured. The results showed that low temperature stress damaged the cell membrane and promoted the defense role of the antioxidant system. Compared with CK, the content of malondialdehyde (MDA) and the enzyme activity of the antioxidant system changed significantly 1 day after low temperature stress. The content of MDA increased by 31.32%, and the activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), peroxidase (POD), ascorbic acid peroxidase (APX) and catalase (CAT) increased significantly by 10.74%, 4 times, 2.22 times, 32.85% and 2.56 times, respectively. In summary, the antioxidant capacity of sugar beet was improved for scavenging the accumulation of reactive oxygen free radicals (ROS) and alleviating membrane damage caused by membrane lipid peroxidation under low temperature stress.