镉在不同类型蕹菜(Ipomoea aquatica Forsk.)中的积累及其化学形态和分子分布  

Accumulation,chemical forms and molecular distribution of Cd in two water spinach genotypes

作　　者：王俊丽[1] 任建国[2] 

机构地区：[1]贵阳医学院公共卫生学院,贵阳550004 [2]贵阳医学院医学生物工程系,贵阳550004

出　　处：《生态学杂志》2014年第6期1594-1600,共7页Chinese Journal of Ecology

基　　金：贵州省三地联合项目(施中药科合专项(2012)6号);贵阳医学院科学基金项目(2012003);广东省高校"千百十"人才工程科研基金资助

摘　　要：采用水培幼苗试验研究不同蕹菜品种（＂台湾308＂和＂强坤青骨＂）Cd的积累及其化学形态和分子分布。结果表明,1.0 mg·L-1Cd浓度处理下,＂台湾308＂和＂强坤青骨＂叶、茎、根Cd含量分别为3.17、3.55、39.1和2.06、2.35、33.5 mg·kg^-1;5.0 mg·L-1Cd浓度处理下,＂台湾308＂和＂强坤青骨＂叶、茎、根Cd含量分别为3.75、4.15、55.8和2.68、3.43、83.7 mg·kg^-1。2个蕹菜品种Cd化学结合形态研究表明,叶中以乙醇提取态为主,茎、根中以乙醇和氯化钠提取态为主。＂台湾308＂叶、茎、根中活性较强的水提取态Cd所占比例均明显高于＂强坤青骨＂,而醋酸和盐酸提取态Cd所占比例均明显低于＂强坤青骨＂。Cd处理水平和蕹菜品种类型对体内Cd化学结合形态均有一定影响,在根中表现尤为明显。分子分布结果表明,蕹菜叶片可溶部分中的Cd大部分与高分子量化合物和小分子量物质相配合,而根中可溶部分的Cd主要与植物螯合肽（PCs）和分子量为10-20 kDa的蛋白质结合。＂强坤青骨＂根系中Cd与PCs配合的组分（Cd-PCs）含量小于＂台湾308＂,降低了Cd向地上部转运的可能性,进而成为其地上部分Cd含量较低的原因之一。Accumulation,chemical form and molecular distribution of Cd in two water spinach varieties,viz. Taiwan308 and Qiangkunqinggu were studied with a hydroponic experiment. The results showed that Cd concentrations in leaves,stems and roots of Taiwan308 were 3. 17,3. 55,39. 1 mg·kg^-1,respectively,which were significantly higher than those of 2.06,2.35,33.5mg·kg^-1correspondingly for Qiangkunqinggu at the treatment of Cd 1. 0 mg·L- 1. Cd concentrations in leaves and stems of Taiwan308 were 3. 75 and 4. 15 mg·kg^-1respectively,which were significantly higher than those of 2. 68 and 3. 43 mg·kg^-1correspondingly in Qiangkunqinggu at the treatment of 5. 0 mg·L^- 1Cd,while Cd concentration in roots of Taiwan308 was55. 8 mg·kg^-1,and obviously less than that of 83.7 mg·kg^-1in Qiangkunqinggu. The results of Cd chemical forms showed that ethanol-extractable Cd was dominant in the leaves,while in the stems and roots,the main forms were ethanol-extractable and NaCl-extractable Cd in the two water spinach varieties. Compared with Qiangkunqinggu in leaves,stems and roots,Taiwan308 had a higher proportion of more mobile H2O-extractable Cd,but a lower proportion of less dissoluble HAc-extractable and HCl-extractable Cd. The levels of Cd concentration and the varieties of water spinach had obvious effects on Cd chemical forms in vivo,especially in roots. The results of Cd molecular distribution showed that the majority of soluble Cd in leaves was bounded to low and high molecular weight components,while in roots Cd was bounded to phytochelatins（ PCs） and some proteins of 10- 20 kDa. The concentration of Cd-PCs in roots of Qiangkunqinggu was lower than that of Taiwan308,which would decrease the Cd translocation from root to aboveground part,finally leading to the lower concentration of the edible parts.

关 键 词：镉 蕹菜 化学形态 分子分布 

分 类 号：X173[环境科学与工程—环境科学]