Chemical Factors Affecting Growth and Development of Lateral Root Formation in Isolated Phaseolus vulgaris L.

Abstract

The initiation and subsequent emergence of lateral roots as secondary roots have been examined in attached and excised roots of Phaseolus vulgaris grown in the absence or presence of indol-3-yl acetic acid (IAA). Treatments with high concentrations of 1AA affected the point at which lateral emergence took place along the primary root. In addition, IAA treatments promoted lateral root emergence from cultured roots of P. vulgaris, which were 1-cm long at the time of excision ; such roots never formed in similar primaries grown in the absence of IAA. No correlation was found between proliferative activity in the meristem at the apex of primary or the rate of root elongation on the one hand and either the number of primordia initiated, or the number of laterals produced, per centimetre of primary, on the other hand.