以玉米品种农大108为试验材料，当玉米幼苗2叶1心时，一部分在常温下（25℃/18℃）培养，另一部分在低温下（10℃/4℃）培养，以叶片喷施0.4 mmol/L亚精胺为处理组，喷施蒸馏水为对照组，研究亚精胺在玉米幼苗冷胁迫过程中的作用。结果表明，低温胁迫抑制了幼苗生长，加剧了叶片中超氧自由基和过氧化氢的产生，提高了膜脂过氧化水平，降低了叶绿素含量。叶片喷施亚精胺，显著缓解了冷胁迫导致的生长抑制、叶绿素含量下降、活性氧积累和膜脂过氧化，提高了幼苗可溶性糖和脯氨酸含量，使抗氧化酶活性显著提高。此外，亚精胺处理提高了冷胁迫条件下幼苗热激蛋白HSP70和HSP90的mRNA和蛋白表达水平。结果表明，外源亚精胺能提高玉米幼苗的抗寒性。

Spermidine(Spd) is an important plant growth regulator and plays a vital role in the environmental stress tolerance of crops. In this study, maize seedling was sprayed with 0.4 mmol/L spermidine on the two leaves and one heart leaf stage as the treatment group and distilled water as the control group. The effects of Spd against chilling stress were investigated in maize seedlings. Low temperature treatment inhibited seedling growth, while the production of superoxide radical(O₂^.-) and hydrogen peroxide(H₂O₂) and the level of membrane lipid peroxidation were increased, and the content of chlorophyll was decreased in chilled maize leaves. However, leaves spraying with Spd markedly alleviated chilling stress-induced growth inhibition, chlorophyll content decrease, ROS accumulation and membrane lipid peroxidation. The content of soluble sugar and proline in seedlings was increased.The antioxidant enzymes avtivities were significantly enhanced in Spd supplied seedlings under chilling condition. In addition, we found that spermidine treatment increased mRNA and protein expression levels of heat shock proteins HSP70 and HSP90 in seedlings under cold stress. In conclusion, exogenous spermidine could improve the cold resistance of maize seedling.

江苏高校优势学科建设工程三期资助项目