Studies in soil and plant manganese - III. The availability of higher oxides of manganese to oats

The availability of six higher oxides of manganese to oats grown in 1% agar nutrient-culture solution has been investigated under sterile and non-sterile conditions. All the oxides were available to the plants to a greater or lesser degree, the order of availability being: - pyrolusite < manganous manganite < an oxide prepared as cryptomelane < γ-manganese dioxide < < manganite < hausmannite. No significant differences in relative relative availability were found as between sterile and non-sterile cultures, although the uptake of manganese was retarded less than the overall yield by the adverse conditions of the sterile cultures.