HCL method for Fe²⁺ estimation to resolve iron chlorosis in plants

Abstract

The equation dictates that acid solutions should not cause reduction of Fe³⁺ during extraction of Fe²⁺ from plants and provide the possibility to preferentially extract Fe²⁺. Both in vitro and in vivo extraction of Fe²⁺ with 1N HCl did not cause reduction of Fe³⁺. Two g chopped fresh plant was reacted with 0.5 to 1.5N HCl and 1:5 to 1:10 tissue:extractant ratios for 24 h. The Fe²⁺ and Fe³⁺ in buffered filterates (pH 3.0) were determined with 1–10 o‐phenanthroline (o‐Ph). 1N HCl and 1:10 ratio resolved better the Fe²⁺ differences between green and iron‐chlorotic plants. Fe²⁺ iron in chlorotic as compared to non‐chlorotic leaves of different crops was 30 to 82%. This method resolved better or equally good, the visible iron chlorosis in plants, compared to o‐Ph method and is much cheaper. The method also eliminates the inherent error arising from extraction of pigments.

Key words:

• Acid fraction
• active iron
• chlorophyll
• Fe²⁺‐Fe³⁺ ‐iron
• Ferroin
• reduction
• in vivo
• in vitro
• iron chlorosis