干旱和镉复合胁迫对紫花苜蓿种子萌发的影响

Interactive Effects of Drought and Cadmium Stresses on Seed Germination of Alfalfa(Medicago sativa L.)

为了探究干旱和镉胁迫对紫花苜蓿种子萌发的影响,本实验以‘中苜强’紫花苜蓿种子为实验材料,研究在不同胁迫浓度镉(0, 1, 5, 10, 50, 100, 200 mg/L)和PEG (0%, 5%, 10%, 15%, 20%, 25%, 30%)以及复合胁迫(Cd, 2.5~25.0 mg/L;PEG, 2.5%~12.5%)下种子萌发的情况。结果表明:(1)在单一镉胁迫下,当浓度≥100 mg/L时对种子的萌发有明显的抑制作用;(2)在单一PEG诱导的干旱胁迫下,浓度高于10%时对种子萌发有明显的抑制作用;(3)在镉/干旱复合胁迫下,Cd^(2+)和PEG尽管未达到单因素胁迫浓度条件却对紫花苜蓿种子的萌发产生了明显的抑制作用,且随着它们各自浓度的增加,抑制作用逐渐增强。本实验结果可为六盘水和其他遭受重金属镉和干旱共同发生地区的植物种子萌发提供理论基础和借鉴意义。

To explore the effect of polyethylene glycol(PEG)-induced drought and cadmium(Cd)stresses on seed germination of alfalfa(Medicago sativa L.),in this experiment,alfalfa seed of'medium-strong'was used as the expe-rimental material.First measured the seed germination,germination potential,germination index and vigor index at the different concentrations of Cd^(2+)(0,1,5,10,50,100,200 mg/L)and PEG(0%,5%,10%,15%,20%,25%,30%).And then,the interactive effects of Cd^(2+)(2.5~25.0 mg/L)and PEG(2.5%~12.5%)on seed germination also analy-zed.The results showed that:(1)The seed germination of alfalfa was apparently inhibited under 100 mg/L and hig-her concentration of Cd 2+;(2)When the concentration of PEGwashigher than 10%,the valuesoffour germination indexes apparently decreased;(3)Interactive effects of PEG and Cd stress were very obvious even if the seeds of al-falfa were not exposed to their stress concentrations.The higher of the respective concentration of PEG and Cd 2+,the stronger of inhibitory effects on seed germination.These results will provide a theoretical basis and reference for plant seed germination in Liupanshui and other areas suffering from heavy metal cadmium and drought stresses.