INFLUENCE OF MANGANESE CONCENTRATION IN NUTRIENT SOLUTION ON THE GROWTH AND ELEMENTAL CONTENT OF THE "KATAHDIN" POTATO PLANT

Abstract

Hoagland’s solutions containing nine levels of manganese ranging from 0 to 100 ppm were applied as a drench tri-weekly to potato plants (Solanum tuberosum L. cv. Katahdin) growing in perlite. Although no deficiency symptoms were observed during the 48-day growing period, varying degrees of toxicity were associated with concentrations of 25.0 ppm Mn and higher in nutrient solution. The tissue concentration necessary to induce toxicity symptoms in foliage appeared to fall between 134 and 426 ppm Mn. Solution concentrations in excess of 25 ppm Mn caused a significant reduction in dry weight of top, root and rhizome portions, and in rhizome number. Increasing Mn treatments generally influenced elemental tissue content as follows: K and Mn increased, Mg decreased, Al and Ca decreased at and above 50 ppm and 75 ppm Mn, respectively, whereas P increased at 50 ppm Mn and above; B, Cu and Mo were unaffected and although N, Fe and Zn contents were somewhat erratic, they were not significantly different at 100 ppm Mn from the control (0.50 ppm Mn).