Effect of Removing Cotyledons, Apical Growing Region, or Trifoliate Leaves on the Growth and Growth-substance Content of Dwarf French Bean (Phaseolus vulgaris)

Abstract

The growth of the primary leaf on intact plants was compared with that on plants from which the cotyledons, apical growing region, or trifoliate leaves had been removed. Removing the cotyledons early decreased the final area of the primary leaves, this response being partially accounted for by a decrease in their cell number, and increased the concentration (but not the quantity) of gibberellin and auxin in them. This response was not altered by applying any of several growth substances. Early removal of the apical growing region increased the final area of the primary leaves; it also increased the gibberellin content and concentration at Day 10 but did not influence the auxin content and concentration. Primary leaf expansion was affected less by detaching young trifoliate leaves than by removing the entire apical growing region.