DISTRIBUTION OF POTASSIUM AND NITRATE IN MAIZE PLANTS GROWN UNDER VARIOUS CONCENTRATIONS OF KNO3 .1. UPTAKE AND DISTRIBUTION OF POTASSIUM

The effects of low (3.5 mmol.1-1) and high (40 mmol.1-1) concentration s of KNO3 in nutrient solution on the uptake and distribution of potas sium in maize plants were investigated. Fresh weight production of ind ividual organs as well as plant growth were inhibited by the excess of KNO3 in nutrient solution. At high KNO3 concentration fresh weight pr oduction was only 41.4% of that of low KNO3 concentration. Growth inhi bition of individual organs increased in a characteristic sequence - r oots, leaves, stem - and correlated with the potassium increase in the se organs. The high concentration of KNO3 also affected potassium (Rb- 86+) uptake rate and potassium transport from roots to shoots. Increas ed transport Rb-86+ from roots to stem and leaves in plants, grown at high KNO3 concentration could explain the relatively low effect of hig h concentration of KNO3 in nutrient solution on the potassium content in roots.