铜在鸭跖草细胞内的分布和化学形态研究

运用差速离心法和化学试剂逐步提取法分析了Cu在鸭跖草Commelina communis根、茎、叶的亚细胞分布及贮存形态.结果表明,细胞壁是鸭跖草根中Cu结合的主要位点,其次为含核糖核蛋白体的细胞溶质部分,而在叶中,Cu主要分布在含核糖核蛋白体的细胞溶质部分中,其次分布在含细胞壁部分;茎中,随着外界Cu浓度的提高,Cu向细胞壁部分的分配减少,而向含核糖核蛋白体的细胞溶质部分的分配增加.根、茎、叶中细胞核、叶绿体和线粒体等细胞器结合Cu量较少.在各种形态铜中,根部以去离子水提取态占优势,茎部和叶部,以去离子水和乙醇两种提取态占优势,其它结合形态的Cu在根中比例较低,在茎、叶中所占的比例有所增加,显示鸭跖草体内Cu的分布特征和形态特征与其耐性和富集Cu有密切联系.

Subcellular Distribution and Chemical Forms of Cu in Commelina communis

The differential centrifugation technique and sequential chemical extraction method were used to study the subcellular distribution and the chemical forms of Cu in the roots, leaves and stems of Commelina communis. The results showed that most of Cu was bound to the cell wall of roots under different Cu concentration in solution. For the leaves, however, Cu was mainly distributed in the soluble fraction.In the stems, increasing Cu supply reduced the percentage of Cu in the cell wall fraction, and increased the mount of Cu in the soluble fraction.Little Cu was found in the cell organelle fraction.For the chemical forms, water extractable Cu predominated in roots, whereas ethanol extractable Cu and water extractable Cu were the main forms in leaves and stems. Other forms such as acetic acid HCl and NaCl extractable Cu were low in roots but high in leaves and stems. The subcellular location of Cu and the chemical forms of Cu has tight relationship with resistance and accumulation in plant.