Manganese Deficiency of Oats and its Relation to Soil Bacteria

Iron Bacteria, particularly those of the Sphaerotilus‐Leptothrix Group, and Industrial Problems

“…A ready oxidation of the manganous compounds to MnO, will occur in the presence of hydroxycarboxylic acids and not in the presence of fatty acids (Sohngen, 1914). This type of reaction can also be shown to exist when certain soil bacteria are streaked on manganese agar plates containing citrate (Sohngen, 1914;Gerretsen, 1937). In comparing oxidation of manganous compounds by these organisms and that by the Leptothrix strains, it appeared that the former process required, in addition to considerable concentrations of hydroxycarboxylic acids, the presence of manganous ions in concentrations which were more than a hundred times higher than those required for the oxidation process by the Leptothrix strains.…”

“…Certain fungi and bacteria not belonging to the Chlamydobacteriales have been found to be able to oxidize manganous compounds (Beijerinck, 1913;von Wolzogen Kiihr, 1927). Nonspecific manganese oxidizing bacteria, forming manganese dioxide in the presence of hydroxycarboxylic acids, are very common in soil (Gerretsen, 1937; see also Siihngen, 1914).…”

The Effect of Micro‐organisms on the Absorption of Manganese by Plants

“…Further, it has been suggested that such microbial products may act as chelating agents (Schatz, 1963;Nicholas, 1965;Arrieta and Grez, 1971) and cause micro-nutrients to remain in solution and, therefore, available for absorption by plants. On the other hand, it has been shown in field and laboratory studies that deficiencies of manganese and zinc (Ark, 1937;Gerretsen, 1937;MacLachlan, 1941;Timonin, 1947;Mulder, Lie and Woldendorp, 1969) may be due to their immobilization by bacteria. Similarly, in a pot experiment, the content of molybdenum was shown to be greater in radishes grown in soil sterilized by irradiation because of the elimination of micro-organisms than in radishes grow^n in untreated soil; micro-organisms reduced the uptake of both native molybdenum and that applied as sodium molybdate (Loutit, 1968).…”

The Effect of Rhizoplane Fungi on the Uptake and Metabolism of Nutrients by Tomato Plants

“…The onset of 'gray-speck' symptoms of oats caused by manganese deficiency has been ascribed to the competition of certain rhizosphere bacteria with the host for the supply of manganese (1). In a similar way, the proneness of oats to 'gray-speck' symptoms in unsterilized soil was related to the preponderance of manganese-oxidizing bacteria in the rhizosphere of a susceptible host (7).…”