Effect of Galactose on Growth and Metabolism of Avena Coleoptile Sections.

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Abstract
Galactose at a concentration of 0.01 [image] inhibits elongation of Avena coleoptile sections quite markedly without affecting non-auxin induced respiration. In lower concentrations which permit growth, C14 derived from galactose-C14 is incorporated into all cell wall constituents except cellulose and protopectin as readily as in C14 from glucose-C14. Incorporation of C14 from galactose-C14 into cellulose is markedly slower than is incorporation of C14 from glucose C14. Galactose at 0.004 [image] has little effect on the incorporation of C14 from glucose into cell wall fractions other than cellulose. Incorporation of glucose carbon into cellulose is strongly repressed by the presence of galactose. Galactose is respired to CO2 but at a lower rate than is glucose. It is suggested that galactose specifically inhibits cell elongation by interfering with cellulose synthesis.