The Effect of Nutritional Factors and Certain Growth Substances on the Growth of Disks Cut from Young Leaves of Phaseolus

Abstract

AbstractThe roles of some chemical factors influencing leaf expansion were investigated using disks cut from the primary leaves of young plants of Phaseolus grown in subdued light. Mineral nutrients, cobalt, sucrose, GA and IAA or NAA at suitable concentrations all caused increases in fresh and dry weights of such disks. When all these substances were applied together the increases in diameter and in fresh and dry weight and cell number were very large and comparable with the rates found in intact leaf tissue. The response of disks to sucrose was found to be light dependent, and a number of other significant interactions were noted. Disks cut from older leaves, in which cell division had ceased, did not show large increases in fresh weight in response to treatment with sucrose, and in this such disks differ from those cut from leaves in which cell divisions are continuing. The possible significance of this is discussed and the roles of light and the other chemical factors investigated are assessed in terms of influence on cell division and expansion in disk tissue.