低温胁迫下脱落酸及合成抑制剂对甘蔗幼苗抗氧化系统的影响

以甘蔗品种桂糖28号为材料,在低温胁迫前12 h用脱落酸(ABA)及合成抑制剂钨酸钠处理甘蔗幼苗,然后于不同时间采集叶片及幼嫩根系样品,测定低温胁迫下丙二醛(MDA)含量、活性氧(ROS)水平、抗氧化酶活性的变化.结果表明:低温胁迫提高了甘蔗幼苗抗氧化酶的活性.ABA处理的甘蔗幼苗ABA含量提高;抗氧化保护酶过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)的活性提高;超氧阴离子自由基(O2-.)、过氧化氢(H2O2)及膜脂过氧化产物MDA含量下降;而ABA合成抑制剂钨酸钠处理的结果则与之相反.说明ABA及合成抑制剂钨酸钠处理对低温胁迫下甘蔗幼苗抗氧化保护系统具有重要的调节作用.ABA对低温胁迫下甘蔗抗寒性的增强可能与ABA对抗氧化保护系统的诱导密切相关.

Effects of Abscisic Acid and Its Biosynthesis Inhibitor on the Activities of Antioxidant System of Sugarcanes Treated by Cold Stress

The sugarcane variety GT28 was employed as materials in this experiment. The young seedlings were sprayed with abscisic acid (ABA) and its biosynthesis inhibitor, sodium tungstate, before 12 h of cold treatment. Leaf +1 and tender root samples were taken at different stages of cold treatment. Malondialdehyde (MDA) contents, active oxygen species (ROS) levels and the activities of antioxidant enzymes were determined during cold stress. The results showed that the activities of antioxidant enzymes increased under cold stress. After ABA application, the content of ABA and the activities of superoxide dismutase (SOD), ascorbic peroxidase (APX), catalase (CAT), peroxidase (POD) and glutathione reductase (GR) increased, while the contents of superoxide anion (O₂^-·), H₂O₂ and MDA decreased in sugarcane seedlings. But when treated by sodium tungstate application, the results were quite the contrary. It can be concluded that ABA and its biosynthesis inhibitor have an important regulatory role in the antioxidant protection system in sugarcane seedlings under cold stress. The cold resistance in sugarcane enhanced by ABA application under cold stress may be associated with the induction of antioxidant protection system.