Studies on the Stolon Development in the Potato Plant : III. Effect of the plant growth regulators on the growth of aerial axillary buds in the potato plants grown from seed tubers

Abstract

Axillary buds of the potato seedlings and of the potato plants grown from seed tubers are different in growth patterns. The objective of this experiment is to make the aerial axillary buds of the potato plant raised from tubers grow stoloniferously by applying growth regulators to the decapitated stem apex. 1. The concentrations of IAA in lanolin paste which were applied at the decapitated stems were progressively increased from 0.5% to 10.0% one treatment changed the IAA concentration every 3 days and the other every 4 days. In addition, intact plants with no treatment, decapitated plants with only plain lanolin and decapitated plants with 1.0% IAA-lanolin (renewed every 3 days) were prepared. (1) Axillary buds in the intact and the decapitated and applied with lanolin plants grew up into the upward, leafy shoots. (2) Axillary buds in the plants with 1.0% IAA-lanolin also resulted in the upward, leafy shoots, although they showed a stoloniferous feature 8 days after the treatment. (3) Axillary buds in the plants applied with the increasing amounts of IAA every 3 days were induced to the stoloniferous shoots, although the internodes were short and the chlorophyll was formed. 2. IAA and GA3 were applied together to elongate the internode length and inhibit the chlorophyll formation of the axillary buds. The ways of treatment were; 1.0% IAA+0.5% GA3 (I), 1.0% IAA→1.0% IAA+0.5% GA3 (II), and 1.0% IAA→1.0% IAA+0.5% GA3→1.0% IAA (III), respectively. (1) Treatment (I) made the leafy, upward shoots, but promoted the elongation of the internodes. (2) Treatment (II) made the upward, leafy shoots gradually, however the orientation of the petiole showed a downward movement. (3) Treatment (III) made the stoloniferous, downward shoots, and the internodes of axillary shoots elongated sufficiently and the cholorophyll development was inhibited. It was suggested that the growth pattern of the axillary buds of the aerial part of potato plant (leafy or stoloniferous) might be hormonally controlled, since the axillary shoots could be partially stoloniferous if suitable amounts of IAA should be applied combined suitable amount of GA3.