The Effects of Growth Regulators on the Geotropism of Leaf Sheath Basal Region in Wheat Plant

Abstract

The present study was carried out to ascertain the influence of growth- regulating substances on the intercalary growth region of the wheat leaf sheath. Stern segments containing a node were used. The growth-stimulating substances, IBA NAA, and 2:4-D, and the growth- inhibiting substances, TIBA and DCA, were mutually antagonistic in their actions on the growth of this region. From the result of histological observation, it was indicated that the growth-stimulating substances promoted the cell elongation of this region and the growth-inhibiting substances inhibited it. Consequently, it was indicated that the negative geotropism of the leaf-sheath basal region in the wheat plant was controlled by synthetic growth regulators. The geotropism of this region had no direct relation with the node and the internode, moreover it was found that there was no dorsiventrality in this region.