一种定量测定水稻根系氧化力的新方法

根系氧化力大小与根表铁膜数量密切相关，铁膜以Fe3+ 形态为主。本文根据水稻根表铁膜数量，探讨了一种测定水稻根系氧化力的新方法。首先，在水稻根系所在溶液中加入定量硫酸亚铁(Fe2+)，处理1天后，水稻根系将一部分Fe2+ 氧化成Fe3+，剩余Fe2+ 用H2O2滴定，得滴定值A。然后，用H2O2滴定没有种植水稻的硫酸亚铁溶液，得滴定值B。根据不种植与种植水稻H2O2的消耗量，滴定值之差(B-A)，即为水稻根系氧化力。该方法要求Fe2+ 浓度大于0.8 mmol/L，过氧化氢消耗量与Fe2+ 浓度成正比(R2 = 0.999 2)。测定过程中，应先加显色剂邻菲罗啉，然后加入磷酸。该方法在不损伤水稻根系情况下可定量测定水稻根系氧化力。

A Novel Method for Quantifying Oxidizing Capacity of Rice (Oryza sativa L.) Roots

Root oxidizing ability is the requisite for the formation of iron plaque on roots surface. Fe3+ is a major form in the iron plaque. Therefore, according to the quantity of iron plaque on roots surface, this paper explored a novel method for quantifying the oxidizing capacity of rice roots. First of all, added quantitative ferrous sulfate (Fe2+) into the culture solution, rice roots would oxidized parts of Fe2+ to Fe3+ after 1 d, remaining Fe2+ in the culture solution was titrated with H2O2, the titration value was A. Then, H2O2 titrated Fe2+ of culture solution without cultivation rice seedlings, the titration value was B. The difference of H2O2 titration value (B-A) was named Root oxidizing ability. This method required: Fe2+ concentration was more than 0.8 mmol/L, H2O2 consumption was proportional to Fe2+ (R2 = 0.999 2). During the determining process, the culture solution was added 1, 10-Phenanthroline monohydrate as colour-display reagent firstly, then added phosphoric acid. This method could quantitatively determine oxidizing capacity of rice roots which were not damaged.