RNA and Protein Synthesis in Germinating Pine Pollen

Abstract

The results of autoradiographic experiments demonstrate that, as with the pollen of most other species, both the generative and vegetative nuclei of Loblolly Pine (Pinus taeda) actively engage in RNA synthesis from the very early stages of pollen germination. Unlike most other species, however, this newly synthesized RNA includes rRNA. Evidence is provided for the importance of this newly synthesized RNA in the process of continued pollen tube growth. One and two-dimensional gel electrophoretic analysis reveals a number of both qualitative and quantitative differences among the proteins synthesized during the early stages of germination and the later stages of pollen tube growth. One of the most notable of these is a 36 kD protein, the synthesis of which predominates during the later stages of pollen germination. A similar pattern of 36 kD protein synthesis is observed when mRNA extracted from pollen at each of these stages is translated in vitro.