铬在芹菜中的累积、亚细胞分布及化学形态分析

采用盆栽试验,研究了Cr6+处理对美国西芹和日本西芹铬总累积量及器官中铬亚细胞分布和化学形态的影响。结果表明,对照处理（0mg·kg-1 Cr6+）芹菜根部和地上部铬在亚细胞中分布为：F3（可溶部分）＞F2（细胞器及膜部分）＞F1（细胞壁及残渣）;40mg·kg-1Cr6+处理为：F1＞F3＞F2,细胞壁(F1)是铬在芹菜细胞内的主要结合位点。芹菜根部和地上部铬化学形态以醋酸提取态占优势,NaCl和HCl提取态也占较大比例。60mg·kg-1Cr6+处理下2个品种芹菜地上部和根部铬含量均极显著增加（P＜001）;相同浓度铬处理下,铬含量和总积累量为：根＞叶＞茎,日本西芹各器官中铬含量和总累积量相对高于美国西芹。2个芹菜品种对铬的吸收均以根部为主要滞留器官,以细胞壁部位为主要的亚细胞分布区域,铬在芹菜体内以难溶性磷酸盐类、蛋白结合态类和草酸盐类为主要化学形态存在形式。

ACCUMULATION,SUBCELLULAR DISTRIBUTION AND CHEMICAL FORM OF CHROMIUM IN CELERY(Apium graveolens L.)

Pot experiment was taken to study the effects of different concentrations of Cr6+ treatments on biomass, accumulation, subcellular distribution and chemical form in two genotypes of celery. The results showed that Cr distribution in subcellular of roots and shoots of control sample was in the order of F3 (soluble fraction) > F2 (cell organs and membrane) > F1 (cell wall and residue), and in sample under 40mg·kg-1 Cr 6+ treatment the order was F1 > F3 > F2, and cell wall was the main Cr combined site in celery. Different distribution ratio of chromium was found in different extraction media, acetic acid extractable-Cr were dominant in both roots and shoots, the amount of chromium extracted by NaCl and HCl were also considerable. Furthermore, the exposure to Cr6+ (60 mg·kg-1) caused markedly increase of chromium content in both roots and shoots(P<001). Under the same concentration of Cr treatment, the contents and accumulated amounts of chromium were in the order of root>leave >stem, and chromium content in Japanese celery was a little higher than that in American celery. It is concluded that chromium was mainly retention in roots, and adsorption in cell wall, existence in the chemical forms of insoluble phosphate, protein|binding and oxalate in two tested genotypes of celery.