【摘要】 为探究低温胁迫下提高烟草耐寒性的苗期外施水杨酸适宜浓度，以NC82为试材，研究11℃低温胁迫后，烟苗在农艺性状、抗氧化酶活性、活性氧代谢等若干生理指标的变化。结果表明：外施水杨酸浓度为1 mmol/L时，相比常温对照处理干物质积累、根系活力及叶绿素含量的降幅最小，而活性氧代谢指标的增幅最小；外施1 mmol/L SA处理后烟苗在前期抗氧化酶活性增幅最大而后期降幅最小。以低温胁迫8 d的各生理生化指标值进行耐寒性评价，耐寒性由强到弱依次为1 mmol/L>0.5 mmol/L>1.5 mmol/L>2 mmol/L>CK₀;综上所述，外施水杨酸浓度1 mmol/L处理对NC82品种的缓解效果最佳，显著降低了低温胁迫后引起的膜脂过氧化程度，提升抗氧化酶活性，减轻了低温胁迫对细胞膜的伤害。更多还原

【Abstract】 To select an appropriate concentration of salicylic acid to improve the cold tolerance of tobacco seedlings under low temperature stress, this study treated the seedlings of tobacco ‘NC82’ subjected to low temperature(11 ℃), with different concentrations of salicylic acid and determined various physiological indices of tobacco seedlings, such as agronomic traits, antioxidant enzyme activity, and active oxygenmetabolism.The results showed that after treatment with 1 mmol/L salicylic acid, the dry matter, root activity, and chlorophyll content of the seedlings were obviously reduced compared to the control, and the active oxygen metabolism was the lowest; the antioxidant enzyme activity showed an increasing trend in the early stage whereas it decreased in the later stage. Cold tolerance was evaluated by analyzing physiological and biochemical indices after seedlings were subjected to low temperature stress for 8 days. The results showed that salicylic acid concentration affected cold tolerance, and seedlings treated with 1 mmol/L salicylic acid showed the highest cold tolerance, followed by 0.5 mmol/L, 1.5 mmol, and 2 mmol/L salicylic acid, and CK. In conclusion, salicylic acid treatment at a concentration of 1 mmol/L had the optimal mitigating effect on tobacco ‘NC82’, which reduced the degree of membrane lipid peroxidation induced by cold stress, increased the activity of antioxidant enzymes, and mitigated the damage to cell membranes caused by cold stress.更多还原