外源水杨酸对低温胁迫下烤烟幼苗生理特性的影响

Effects of Exogenous Salicylic Acid on Physiological Characteristicsof Flue-Cured Tobacco Seedlings under Low Temperature Stress

为揭示外源水杨酸对提高烤烟幼苗抗低温能力的生理效应,以云烟87为供试品种,运用人工气候培养箱模拟4℃低温,设置不同浓度(0、0.6、0.8、1.0和1.2mmol/L)水杨酸对烤烟幼苗连续3d进行叶面喷施预处理,随后进行连续5d的低温处理,以25℃、喷施蒸馏水作为对照,测定烤烟幼苗活性氧代谢、抗氧化酶活性、渗透调节物质含量和根系活力的影响。结果表明,低温胁迫下烤烟幼苗活性氧增加,膜脂过氧化程度加剧,抑制幼苗的生长发育。而外源水杨酸能够明显提高低温胁迫下烤烟幼苗的抗氧化酶活性,增加渗透调节物质含量,降低O^(-)_(2)·产生速率和MDA积累量,缓解低温胁迫对烤烟幼苗的损伤,增强其抗低温能力。

In order to reveal the physiological effects of exogenous salicylic acid on improving the low temperature resistance of flue-cured tobacco seedlings,Yunyan 87 was used as the material,and artificial climate incubator was used to simulate 4℃ low temperature.Different concentrations(0,0.6,0.8,1.0 and 1.2mmol/L)of salicylic acid were set up to pretreatment on flue-cured tobacco seedlings for three days,followed by five days of low temperature treatment.With 25℃ and spraying distilled water as control,the effects of active oxygen metabolism,antioxidant enzyme activity,osmotic adjustment substance content and root activity of flue-cured tobacco seedlings were measured.The results showed that,under low temperature stress,the reactive oxygen species of flue-cured tobacco seedlings increased,and the degree of membrane lipid peroxidation increased,which inhibited the growth and development of seedlings.Exogenous salicylic acid could significantly improve the antioxidant enzyme activity of flue-cured tobacco seedlings under low temperature stress,increase the content of osmotic adjustment substances,reduce the O^(-)_(2)·production rate and MDA accumulation,alleviate the damage of low temperature stress on flue-cured tobacco seedlings,and enhance their low temperature resistance.