外源亚精胺对PEG胁迫下燕麦幼苗生长及部分生理特性的影响

为探讨外源亚精胺(Spd)对燕麦幼苗生长和抗旱性的影响,选用燕麦品种坝莜1号为材料,以PEG-6000模拟水分胁迫,采用砂培法研究了叶面喷施不同浓度(0.3、0.6、0.9和1.2mmol·L~(-1))外源Spd后燕麦幼苗生长、活性氧代谢、抗氧化酶活性及非酶抗氧化剂和渗透调节物质含量的变化。结果表明,PEG胁迫显著抑制了燕麦幼苗生长。在PEG胁迫下,与只喷施蒸馏水的对照相比,0.6mmol·L~(-1) Spd处理对燕麦幼苗根系活力、抗坏血酸(ASA)含量和抗坏血酸过氧化酶(APX)活性具有显著的促进作用;喷施0.9mmol·L~(-1)外源Spd明显提高了燕麦幼苗的株高、根长、生物量积累,抑制了O_2~-·、H_2O_2和膜脂过氧化产物MDA的生成,增强了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和谷胱甘肽还原酶(GR)的活性,降低了游离氨基酸含量,促进了脯氨酸、可溶性糖和可溶性蛋白的积累,维持了较高的渗透调节能力;1.2mmol·L~(-1)外源Spd处理后幼苗生长、抗氧化能力和渗透调节作用出现下降趋势。综合来看,在PEG胁迫下,叶面喷施0.9mmol·L~(-1)Spd可通过提高幼苗抗氧化和渗透能力,维持生物膜系统的稳定,减轻渗透胁迫对幼苗的伤害,促进生长和增强抗旱性。

Effect of Extraneous Spermidine on Growth and some Physiological Characteristics in Oat Seedlings under PEG Stress

In order to explore the effects of different concentrations of extraneous spermidine(Spd) on the drought resistance of oat seedling,under water stress simulated by PEG-6000,"Bayou 1" ,an oat variety,was used as the material with sand culture methods under different concentrations of extraneous spermidine (0.3 mmol·L-1, 0.6 mmol·L-1, 0.9 mmol·L-1, and 1.2 mmol·L-1)to study its effects on oat seedling growth, reactive oxygen species metabolism and the content of antioxidant enzymes and osmotic regulation substances.The results showed that osmotic stress significantly inhibited the growth of oat seedlings.Exogenous Spd with concentration of 0.6 mmol·L-1 application significantly promoted root activity, ASA and APX contents of oat seedlings.Exogenous Spd with concentration of 0.9 mmol·L-1 application significantly increased plant height, root length and biomass accumulation, but inhabited the formation of O-·2, H2O2 and MDA and induced to enhance the activities of SOD, CAT, POD and GR in antioxidant system.Moreover, the total amount of free amino acid was reduced and the accumulation of proline, soluble sugar and soluble protein of organic solutes were promoted, and finally maintained a high osmotic buffer and adjustment capability.Exogenous Spd with concentration of 1.2 mmol·L-1 application showed a decreasing trend in physiological responses.According to the physiological and biochemical indices, under water stress, extraneous 0.9 mmol·L-1 Spd could protect the stability of the biological membrane system through the promotion of anti-oxidase activity and ascorbic acid (ASA), glutathione (GSH) content.The damage caused by water stress was reduced, while the drought resistance of oat seedlings was enhanced.