Abstract: Two rice varieties, cv. Chugoko 91 (japonica, moderately salt sensitive) and cv. 83-51 (indica, salt sensitive),were grown in Espino cultural solution for 12-16 days after 3 days of germination (day/night temperature was 32℃/20℃ and PPF was about 600 μmol/m²s). Rice seedlings were pre-treated with 0.1% NaCl for 8 days before being subjected to 0.3% NaCl stress. Results showed that during the period of salt treatment, the dry weight increase velocity of rice seedlings using 0.1% NaCl pre-treatment was 17% and 47% greater than those without 0.1% NaCl pre-treatment in two varieties, respectively. The activities of superoxide dismutase and catalase were stimulated by 0.1 % NaCl pre-treatment,so they remained a higher level when subjected to 0.3% NaCl treatment compared to those without 0. 1 % NaCl pre-treatment. Although peroxidase activity, the content of malonyldialdehyde (MDA). production of lipid peroxidation and Na+ content increased slowly in rice seedlings during 8 days of 0.1% NaCl pre-treatment, the increase rate of them was much lower during subsequent salt stress and thus made them in lower level. Furthermore, K⁺ content decreased during both 0.1% NaCl pre-treatment and 0.3% NaCl treatment, while changing range during 0.3% NaCl treatment was less in seedling pretreated with 0.1 % NaCl than those without 0.1% NaCl pre-treatment. These results suggested that pre-treatment using low concentration of salt could improve the ability of defence system in rice seedlings and prevent them from salt injuries induced by active oxygen, thus enhanced salt tolerance of rice.

Key words: lipid peroxidation, low concentration salt pre-treatment, salt tolerance, superoxide dismutase

摘要： 研究了幼苗期低盐锻炼对水稻耐盐能力的影响。中国91和83-51幼苗经低盐(0.1% NaCl)锻炼后可降低盐处理(0.3% NaCl)对其生长的抑制; 低盐刺激叶片超氧化物歧化酶和过氧化氢酶活性升高,从而在盐胁迫时保持较高活性;虽然低盐也使过氧化物酶活性、丙二醛含量以及Na+含量有一定程度的增加,但在盐胁迫时其增加速率明显减慢而低于未经低盐锻炼的苗株；相反，低盐锻炼时K+含量有所下降，但在盐胁迫时其下降幅度低于未经低盐锻炼的植株，至处理结束,两者水平接近。结果表明,幼苗期采用低盐锻炼的方法可以增强水稻的耐盐能力, 这与低盐锻炼可在一定程度上增强地上部组织内清除活性氧的防护系统能力, 使其在随后的盐胁迫过程中由活性氧诱导脂质过氧化作用产生的盐渍伤害减轻有关

关键词: 耐盐性, 低盐锻炼, 超氧化物歧化酶, 脂质过氧化作用