镉对紫花苜蓿种子萌发等生理特性的影响

Effect of Cd^(2+) on physiological characteristics of alfalfa

以阿尔冈金(Algonquin)和新疆大叶(M. sativa L. cv. xinjiangdaye)种子为试验材料,研究了0~5mg/L浓度的Cd2+处理对其种子生理特性的影响。结果表明:低浓度和高浓度的Cd2+对二者种子的发芽势和发芽率均有抑制作用,而中间浓度却有促进作用,呈现"下降-回升-下降"的现象;发芽指数和活力指数,均随着Cd2+浓度的增大而下降;与对照相比,随Cd2+处理浓度的增大,阿尔冈金和新疆大叶的下胚轴、根长、苗长、地上部分鲜重、地下部分鲜重都随之降低,但新疆大叶降低的幅度更大一些;随着Cd2+处理浓度的升高,阿尔冈金和新疆大叶的脯氨酸、电解质泄漏率、丙二醛(MDA)含量都随之增大;但在同浓度的Cd2+处理下:幼苗叶片中的脯氨酸含量:新疆大叶>阿尔冈金;电解质泄漏率:新疆大叶<阿尔冈金;丙二醛(MDA):新疆大叶<阿尔冈金。试验表明,优良牧草紫花苜蓿的两个品种中,阿尔冈金对Cd2+胁迫的耐受能力要强于新疆大叶。

With an experiment, the effect of Cd^2＋ for 0 - 5 mg/L on physiological characteristics of alfalfa varieties Algonquin and Xinjiangdaye was studied. The results show that the Cd^2＋ treatment at lower concentration and at higher concentration can decrease the germination rates and the germination vigor, the middle Cd^2＋ treatment can increase the germination rates and the germination vigor. It is shown that ＂decreasing-increasing- decreasing＂. With the Cd^2＋ treatment increasing, the germination index and vitality index were decreasing, hypocotyl length, root length, shoot length, fresh weight on and under ground were decreasing. With the Cd^2＋ treatment increasing, proline contents, permeability of plasmalemma and MDA contents were increasing. With the same Cd^2＋ treatment, proline contents： Xinjiangdaye is higher than Algonquin;permeability of plasmalemma：Xinjiangdaye is lower than Algonquin; MDA contents： Xinjiangdaye is lower than Algonquin. The experiment may suggest that Algonquin is stronger to resist against Cd^2＋ stress than Xinjiangdaye.