Fig. 1.

Scanning electron micrographs (A, B and C) and energy-dispersive X-ray analysis (EDAX) (D, E and F) of precipitates formed on rice (Koshihikari) roots in hydroponic culture supplemented with iron or aluminium. (A) Rice was grown in Kimura B nutrient solution (pH 4·5) containing 30 mg L⁻¹Fe(II)-EDTA for 6 d (Method I). (B) Rice was pre-treated with a solution (pH 4·5) containing 30·0 mg L⁻¹ FeSO₄ for 12 h (Method II). (C) Rice was not pre-treated with iron but was exposed for 24 h to 0·5 mm CaCl₂ solution (pH 4·5) containing 50 μm AlCl₃. (D), (E) and (F) correspond to (A), (B) and (C), respectively. These micrographs are representative of the general morphology and image.