外源亚精胺对盐胁迫下白刺幼苗叶片抗氧化酶系统的影响

为进一步阐明盐生植物白刺耐盐性与多胺的关系,通过水培试验研究了叶面喷施亚精胺(Spd)对不同浓度NaCl胁迫下西伯利亚白刺幼苗叶片丙二醛(MDA)和超氧阴离子(O2)产生速率,以及抗氧化物酶系统和根系活力的影响.结果表明:叶面喷施0.1 mmol·L1 Spd 5 d后,可显著提高100和200 mmol·L1 NaCl胁迫下白刺幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性以及根系活力,降低了叶片MDA含量和O2的产生速率；而在0、50、300 mmol·L-1 NaC1处理下,外施Spd对白刺幼苗叶片上述指标无显著影响.研究结果证实,在100～200 mmol·L-1 NaCl胁迫范围内,外施亚精胺可能通过增强体内保护酶活性来显著降低活性氧水平,有效减轻盐胁迫对盐生植物白刺幼苗造成的过氧化伤害,从而增强白刺对盐环境的适应性.

Effect of Exogenous Spermidine on Antioxidant Enzyme System in Leaves of Nitraria sibirica Pall.Seedlings under Salt Stress

To further elucidate the relationship of spermidine and salt tolerance of halophyte Nitraria sibirica Pall.,under different levels of salinity in hydroponics condition,we studied the effect of spermidine on malondialdehyde (MDA),superoxide anion (O^-·₂) and the antioxidant enzyme system in leaves of N.sibirica seedlings.The result showed that in treatment groups (100 mmol·L^-1 NaCl and 200 mmol·L ^-1 NaCl),the activities of superoxide dismutase (SOD),peroxidase (POD) and catalase (CAT) in leaves of N.sibirica seedlings and the activity of root system were significantly increased,while the content of the MDA and O^-·₂ in leaves were reduced in 5 d after foliage spray of spermidine (0.1 mmol·L^-1).In treatment groups (0,50 and 300 mmol·L ^-1 NaCl),there was no obvious effect on leaves of N.sibirica seedlings after treatment of exogenous spermidine.The results showed that under 100 mmol·L^-1 to 200 mmol·L ^-1 NaCl stress,exogenous spermidine can effectively reduce the injury to N.sibirica and enhance the adaptability in salt environment.