Ultrastructural and metabolic transformations of differentiating Hyacinthus orientalis L, pollen grain cells. I. RNA and protein synthesis

Abstract

RNA and protein synthesis were investigated in generative and vegetative cells during maturation of pollen grains. The rate of RNA and protein synthesis was analysed in reference to the successive interphase periods of the life cycle of pollen cells as well as against the background of the growth dynamics of the cell volume. The results of studies demonstrated that the pollen grain increases in size owing to the growth of the vegetative cell. The generative one does not grow. RNA synthesis and that of proteins in differentiating pollen cells has a different course. In the growing vegetative cell it lasts longer and is more intensive than in the generative cell which does not grow. RNA and protein synthesis in the vegetative cell take place in the period from the callose stage to the stage of lemon-shaped generative cell, that is in the period of phases G₁, S and G₂. This synthesis is positively correlated with the growth of the pollen grain. RNA and protein synthesis in the generative cell comprises the period from the callose-less lenticular stage to the stage of spherical generative cell, that is the phases S and early phase G₂. These results suggest that in the vegetative cell RNA and protein synthesis is utilised above all to increase of its cell, instead in non growing generative cell protein synthese is probably limited mostly to a histones and enzymatic proteins serving for the DNA replication process.