MANGANESE EFFICIENCY IS EXPRESSED IN BARLEY GROWING IN SOIL SYSTEM BUT NOT IN SOLUTION CULTURE

Manganese (Mn) efficiency among barley (Hordeum vulgare L.) genotypes was demonstrated in soil culture under field and laboratory conditions. In the soil culture, Mn efficiency was expressed in the field in terms of vegetative growth and relative grain yield. Manganese efficiency was also expressed under controlled conditions in terms of dry matter production and Mn concentration in plant tissues. However, in chelate-buffered nutrient solution at pH 6.0 in which Mn was supplied as Mn2+ buffered by N-(2-hydroxyethyl)ethylenedinitrilotriac acid (HEDTA), Mn efficiency was not expressed, either in terms of dry matter production, Mn concentration, or Mn accumulation. Thus, we have concluded that Mn efficiency in barley was not related to differences in the rate of Mn2+ uptake, but may involve some process which enhances the availability of soil Mn to plant roots.