镧对酸雨胁迫下水稻萌发种子POD与质膜透性动态变化的影响

EFFECT OF LANTHANUM ON POD AND MEMBRANE PERMEABILITY OF RICE UNDER ACID RAIN STRESS

采用模拟酸雨和镧复合处理水稻(O.sativao)种子,测定不同酸雨胁迫强度下镧对种子质膜透性(E%)和过氧化物酶(POD)活性的影响.结果表明,用pH4.0和pH2.5的酸雨连续胁迫7d,随着胁迫时间的增加,水稻种子的质膜透性呈现先减小后逐渐增大再减小的趋势,过氧化物酶(POD)活性一直保持升高的趋势.经镧处理后,水稻种子的质膜透性变小,POD活性有所增高.而在第5天和第3天,pH=2.5和pH=4.0酸雨胁迫下的水稻种子换用隔夜自来水培养,使得其质膜透性有所减少,过氧化物酶活性得以回升.镧对种子的萌发具有一定的防护效应,减轻了酸雨对萌发期间的伤害程度,增强了种子抗酸雨的能力.

To explore if rare earth element lanthanum could protect from the damage of the germination of rice seed under different acid rain stresses, the activity of peroxidase （POD） and the membrane permeability were investigated. Two simulated acid rain （SAR） solutions of pH 2. 5 and 4. 0, and neutral solution as control group were used in this study. Rice seeds pretreated with lanthanum were placed in culture dishes and kept at the normal temperature, in which each treatment group involved three dishes and each dish received 50 seeds. During germination, seeds were exposed to simulated acid rain that was replaced everyday to keep a certain pH. The results showed that under the stress of constant acid rain （ pH = 4. 0 and pH = 2. 5 ） for 7 days, with the increasing stress time, the change trend in the membrane permeability of the rice seeds were followed the order ： ＂ increase-decrease-increase＂ . And the activity of POD was increased during all the time. The membrane permeability of the rice seeds was decrease and the activity of POD of rice seed treated with lanthanum were increased compared with that of only stress of acid rain. When cultivated with control solution instead of acid rain （ pH = 2.5 and pH = 4. 0） after 5 days, the membrane permeability was decreased, and the activity of POD were increased compared with that of stress of acid rain for 7 days. The results in this study showed that lanthanum could alleviate the damage of acid rain to germination of rice seeds by increasing the ability to repair by themselves of the rice seeds.