铅镉胁迫下马齿苋的种子萌发和幼苗生理响应

以马齿苋为试验材料，通过水培法研究马齿苋在铅、镉单一胁迫下种子萌发及幼苗生理指标的影响。结果表明：低浓度的铅胁迫对马齿苋种子萌发影响不大，但高浓度则显著抑制其种子萌发，2 000 mg/L铅处理下失去萌发能力；镉胁迫下则表现为低浓度促进高浓度抑制。随着铅胁迫浓度的升高，马齿苋体内可溶性蛋白、可溶性糖、游离脯氨酸含量和超氧化物歧化酶、过氧化物酶、过氧化氢酶活性下降；而随着镉胁迫浓度的升高，渗透调节物质含量和抗氧化酶活性则呈先升高后降低的趋势。

Response of Pb and Cd on Seed Germination and Seedling Physiologica of Portulaca oleracea

Using Portulaca oleracea as experimental plant, through the hydroponic experiments,the seed germination and seedling physiological indexes under Pb, Cd stress were studied. The results showed that low concentration of Pb treatment had little effect on the seed germination, while severely inhibited under higher Pb concentrations, when the treatment dosage of Pb reached to 2 000 mg/L, seeds lose their germination power. Moreover, low concentration of Cd treatment promoted seed germination, while higher concentration of Cd inhibited seed germination.With the increasing of the Cd concentration,contents of soluble protein, soluble sugar,free proline and activity of SOD, POD, CAT of P. oleracea decline significantly. However, with the increasing of the Cd concentration, the osmotic substances and anti-oxidative enzyme activity increased first and then declined.