铅、镉单一及复合污染对11个空心菜品种种子萌发和幼苗生长效应的影响

李富荣　朱娜　杨锐　杜应琼　王富华

摘 要 以11个品种的空心菜种子为研究对象，研究了不同浓度的铅、镉及其复合污染对不同空心菜种子萌发率、幼苗根长、苗高及生物量的影响，比较了不同处理对空心菜种子萌发和幼苗生长抑制效应的品种差异，旨在为重金属中轻度污染农田土壤栽培空心菜的品种选择及农产品质量安全保障提供参考。结果发现：铅、镉单一或复合污染对幼苗生长比种子萌发的抑制作用更明显，其中幼苗根生长对铅镉污染比种子萌发等指标更为敏感，因此将幼苗根生长作为评价重金属铅镉毒害的指标更为合理。随着铅、镉单一及铅镉复合污染浓度的加大，其对空心菜各品种幼苗生长的抑制作用也逐渐增大，且同样浓度下，铅镉复合污染往往比单一重金属污染的抑制率更高，说明铅镉污染存在协同效应。其中，对空心菜各指标的综合抑制效应在铅、镉单一污染下最高达48.78%和42.84%，而在铅镉复合污染时最高达59.73%。另外，不同品种对铅、镉污染的敏感性不同，通过比较，区分了3个耐铅镉污染品种和2个铅镉污染敏感品种。

关键词 铅；镉；空心菜；复合污染；种子萌发

中国分类号 S181 文献识别码 A

Abstract To screen suitable cultivars in heavy metal polluted agricultural soils and reduce the risk of pollutants entering the human diet from soils via agricultural products， the variations in inhibitory effects of simplex / combined Pb and Cd pollution on the seed germination and seedling growth of different Ipanoea aquatica cultivars were studied. The results showed that seedling growth reflected the effects of Pb and Cd pollution on I. aquatica even more than the seed germination. Among them， root growth which was the most sensitive to lead and cadmium pollution could be used as the important index to assess the toxic effect of heavy metal lead and cadmium. As heavy metal pollution concentrations increased， the inhibitory effect of simplex / combined Pb and Cd pollution on seedling growth of I. aquatica was strengthened. Additionally，under the same concentration of some heavy metal element，the combined pollution usually caused higher inhibition rates than the simplex pollution. It was suggested that there was a synergistic effect between lead and cadmium pollution. The maxmium comprehensive inhibitory effects of all parameters under simplex Pb and Cd pollution was 48.78% and 42.84%， respectively， while the maxmium value under combined pollution was 59.73%. Besides， different cultivars showed different sensitivity to lead and cadmium pollution. There were three cultivars to be considered as the tolerant cultivars to lead and cadmium pollution and two cultivars to be sensitive cultivars.

Key words Lead； Cadmium； Ipanoea aquatica； Combined pollution； Seed germination

doi 10.3969/j.issn.1000-2561.2015.11.006

铅（Pb）和镉（Cd）是环境中重要的有毒重金属，其所带来的环境污染问题和食品安全问题广受关注。铅作为对生态环境危害极大的重金属元素之一，进入土壤后不能被微生物降解，很难去除，对植物和动物都会产生较大的毒害[1-2]。而镉在土壤中的有效态比例较高，活性较强，很容易被作物吸收而污染食物鏈，危及人类健康[3]。……