重金属对油菜种子萌发和胚根生长的影响

分析了Hg2 、Cd2 、Ni2 、Co2 、Zn2 5种重金属离子对油菜种子萌发和胚根伸长的影响,以及金属离子K 、Mg2 和Ca2 与重金属的交互作用。结果表明:(1)重金属对油菜种子萌发的抑制作用依次为Hg2 >Cd2 和Co2 >Ni2 >Zn2 ,而对胚根生长的毒害作用依次为Hg2 >Cd2 >Co2 >Ni2 >Zn2 。(2)萌发率为40%以上时,K 和Ca2 可以提高Ni2 、Zn2 和Co2 胁迫下油菜种子的萌发率,却进一步降低了Hg2 、Cd2 胁迫下种子的萌发;Mg2 可以提高Ni2 、Zn2 、Cd2 和Co2 胁迫下种子的萌发率,但对Hg2 毒害却没有缓解。(3)胚根伸长率达到60%以上时,K 和Mg2 增强了Ni2 、Hg2 、Cd2 和Co2 对胚根生长的抑制,而Ca2 则缓解了Zn2 、Ni2 和Co2 对胚根生长的抑制作用。研究结果对于重金属复合污染土壤中植物种子的萌发和定植具有理论和实践意义。

Effects of Heavy Metal Ions on Seeds Germination and Radicle Growth of Brassica napus

Heavy metals had different effects on seed germination and radicle growth.Toxicity of five types of heavy metal ions (Hg2 ,Cd2 ,Ni2 ,Co2 and Zn2 ) on the initial growth of Brassica napus and whether the application of K ,Mg2 and Ca2 could alleviate the effects of heavy metals on the seeds germination and radicle growth of B.napus were investigated.The results showed that radicle growth was more sensitive to heavy metals than seed germination.Zn2 was not very toxic to seed germination but was to radicle growth.Hg2 was the most toxic metal for plant growth and development.K and Ca2 slightly alleviated the toxicity of Ni2 ,Zn2 and Co2 to seed germination,while slightly increased the toxicity of Hg2 and Cd2 .Mg2 was effective to reduce the toxicity of Ni2 ,Zn2 ,Cd2 and Co2 on seed germination,but was not influence to Hg2 .The toxicity of Ni2 ,Hg2 ,Cd2 and Co2 on radicle growth was partially enhanced in the present of 5 mmol/L K and Mg2 while Ca2 partially restored the inhibition of Zn2 ,Ni2 and Co2 .The researches are helpful for further research on elucidating fundamental mechanism of heavy metal tolerance and cultivating plants on heavy-metal-contaminated soil.