Effects of hormones, leaf removal and light intensity on growth and apical dominance of dwarf bean : A dissertation submitted in partial fulfilment of the requirements for the Diploma of Horticultural Science in the Lincoln Agricultural University College

Abstract

The growth responses of dwarf bean (Phaseolus vulgaris variety Canadian Wonder ) to hormones applied to the soil, leaf removal and light intensities has been studied and found as follows: (1) GA₃ at both high and low concentrations, i.e. 50ppm and 10ppm increase the growth of main stem.

(2) IAA or kinetin have no effect on growth of main stem.

(3) GA₃ is the only hormone to promote growth of lateral shoots growth although kinetin seems to annul the effects of GA₃.

(4) Removal of two young leaves decreases the length of main stem but increases the growth of laterals.

(5) Removal of large leaves decreases the growth of both stems and laterals.

(6) Low light intensity stimulates stem elongation but it has no effect on lateral growth except under high GA₃ levels.

(7) Some effects of hormones, especially high concentration of GA₃ and low concentration of IAA on root weight were found in experiment 1 but similar results were not obtained in experiment 2.

(8) Top weight was increased by high concentration of GA₃ and kinetin in experiment 1 but not in experiment 2.