硅/砷比对水稻剑叶和根系中砷亚细胞分布的影响

Subcellular distribution of arsenic in flag leaf and root of rice with different ratios of silicon to arsenic

以水稻品种‘Italica carolina’为试验材料,分别生长在含有As^(Ⅲ)和As~Ⅴ介质中3 d,采用营养液培养方法和亚细胞组分分级技术,研究了不同硅/砷比对水稻剑叶和根中砷亚细胞分布特征的影响。结果显示,水稻无论生长在As^(Ⅲ)或As~Ⅴ条件下,根系和剑叶亚细胞不同组分中砷含量顺序为:胞液>细胞壁>细胞器。从水稻根中砷的亚细胞分布来看,As^(Ⅲ)培养条件下加硅明显降低了根系砷在亚细胞组分中的分布,且硅/砷比10:1时根细胞器和胞液中砷的含量最低;而在As~Ⅴ培养条件下,仅硅/砷比200:1处理显著降低了根系胞液组分中的砷含量(P<0.05)。从水稻剑叶中砷的亚细胞分布来看,As^(Ⅲ)培养条件下硅/砷比10:1显著降低了胞液和细胞壁中的砷含量(P<0.05)且达到了最低值,而细胞器中砷含量在硅/砷比1:1时达到最低;As~Ⅴ培养条件下,不同硅/砷比并没有明显影响砷在剑叶中的亚细胞分布。

A hydroponic experiment was conducted to investigate subcellular distribution of arsenic（As） in flag leaf and root of rice（‘Italica carolina＇） exposed to As^（Ⅲ） and As~Ⅴ solutions with different ratios of silicon（Si） to arsenic for 3 days. Results showed that regardless of whether As^（Ⅲ） or As~Ⅴ was supplied to rice, As concentrations in different fractions of root and flag leaf followed the same pattern： cytoplasmic supernatantcell wallorganelle. When supplied with As^（Ⅲ）, As concentrations in subcellular fractions of roots were significantly decreased by Si addition, with lowest concentrations of As in cytoplasmic supernatant and organelle fractions of roots with Si/As at 10：1. Whereas, when suppllied with As~Ⅴ, only at Si/As 200：1 dramatically reduced the As concentration in cytoplasmic supernatant of root（P〈0.05）. For the subcellular distribution of arsenic in rice flag leaves, when supplied with As^（Ⅲ）, the As concentrations in cytoplasmic supernatant and cell wall reduced signifi-cantly with Si/As at 10：1（P〈0.05） and reached the minimum level, while lowest As concentration in organelle parts of leaves were found at Si/As 1：1. However, there was no significant effect on subcellular distribution of arsenic in flag leaves when As~Ⅴ supplied in the nutrient solution.