Riboflavin as Photoreceptor in the Induction of Two-dimensional Growth in Fern Gametophytes

Publisher Website
Google Scholar
Abstract
By supplementing the mineral salt solution with either 2-thiouracil, 2-thiocytosine or phenazinej 2-dimensional growth of the gametophyte of Phymatodes nigrescens (Bl.) J.Sm,, is completely inhibited at optimal concentrations of 2.0 mg/1, 35 mg/1 and 6.0 mg/1 respectively. The inhibitory effects of these analogs is reversed completely by the addition of riboflavin to the inhibitors at 30.0 - 35.0 mg/1 and the 2-dimensional growth is reinstated. The addition of lumichrome with 2-thiouracil, a specific base analog of RNA resulted in still better reversal. Reversals to 2-dimensional growth could occur only in the presence of either blue or white light, while red light enhanced 1-dimensional growth even when riboflavin is supplied at optimum reversal concentrations. The possible significance of the biosynthesis of a flavoprotein (riboflavin) from the corresponding pyrimidines which act as a photoreceptor in white or blue light is discussed.