镉离子胁迫下钙镁离子对水稻种子萌发期耐镉性的影响

Effects of Calcium and Magnesium Ions on Cadmium Tolerance in Rice Seed Germination under Cadmium Ion Stress

以西南地区主栽水稻品种Q优6号为材料,采用温室发芽试验,研究Cd^2+胁迫下Ca^2+、Mg^2+对水稻发芽率、生长量及根芽中镉含量的影响。结果表明:在1 mg·kg-1 Cd 2+浓度(简称1 Cd)胁迫下,随着Ca^2+浓度的增加,水稻发芽率、发芽指数逐渐增加,随着Mg^2+浓度的增加,水稻发芽率、发芽指数逐渐降低;在2 mg·kg^-1 Cd^2+浓度(简称2 Cd)胁迫下,Ca 2+使水稻发芽率、发芽指数均提高22.53%,随着Mg^2+浓度的增加,水稻发芽率、发芽指数先降低后增加。在1 Cd胁迫下,随着Ca^2+浓度的增加,水稻生物量逐渐增加,在2 Cd胁迫下,随着Ca^2+浓度的增加,水稻生物量逐渐降低;在1 Cd胁迫下,Mg^2+对水稻生物量生长的强弱关系为1 Cd+3 Mg>1 Cd+1 Mg>1 Cd+2 Mg;在2 Cd胁迫下,随着Mg 2+浓度的增加,水稻生物量逐渐增加。在1 Cd胁迫下,随着Ca^2+、Mg^2+浓度的增加水稻根系中Cd的含量先增加后降低,水稻芽中Cd含量均呈降低趋势;在2 Cd胁迫下,水稻根芽中Cd的含量均随着Ca^2+、Mg^2+浓度的增加而降低。因此,Cd^2+胁迫下添加Ca^2+、Mg^2+能够增加水稻发芽率、发芽指数、活力指数,增强水稻种子萌发期生物量与生长量,降低根系与芽中Cd的含量。

In order to explore the effects of Ca^2+and Mg^2+on the cadmium tolerance of rice seed germination under the Cd 2+stress,the main cultivated rice cultivar Qyou 6 in southwest China was selected as experimental materials to investigate the effects of Ca^2+and Mg^2+on the germination rate,growth and cadmium accumulation in rice under the Cd^2+stress by greenhouse germination test.The results showed that under the stress of 1 mg·kg^-1 Cd^2+concentration(referred to as 1 Cd),the germination rate and germination index of rice increased gradually with the increase of Ca^2+concentration,while the germination rate and germination index of rice decreased gradually with the increase of Mg^2+concentration.And,under the stress of 2 mg·kg-1 Cd^2+concentration(referred to as 2 Cd),the germination rate and germination index of rice were both promoted by calcium ions by 22.53%.With the increase of Mg^2+concentration,the germination rate and germination index of rice decreased first and then increased.Under the stress of 1 Cd,the rice biomass gradually increased with the increase of Ca^2+concentration,while under the stress of 2 Cd,the rice biomass gradually decreased with the increase of Ca^2+concentration.In addition,under the stress of 1 Cd,the relationship of Mg 2+to the growth of rice biomass manifested as 1 Cd+3 Mg>1 Cd+1 Mg>1 Cd+2 Mg.Under the stress of 2 Cd,rice biomass gradually increased with the increase of Mg^2+concentration.Under the stress of 1 Cd,with the increase of Ca^2+and Mg^2+concentrations,the content of Cd in rice roots first increased and then decreased,and the content of Cd in rice buds showed a continuously decreasing trend.Simultaneously,under the stress of 2 Cd,the content of Cd in rice root buds decreased with the increase of Ca^2+and Mg^2+concentrations.Therefore,the addition of Ca^2+and Mg^2+under the stress of Cd^2+could increase the germination rate,germination index and vigor index of rice,enhance the biomass and growth of rice seeds during germination,and reduce the Cd content in roots and buds.