In vitro translation capacity of ribosomes isolated from the cells of pine buds during the cold season

The cytosolic and membrane‐bound ribosome assemblies were isolated from the microsporangiate strobili of Scots pine (Pinus sylvestris L.). Both assemblies studied were able to incorporate [3H]‐leucine into trichloroacetic acid‐insoluble material throughout the sampling period from October to April, indicating that the isolation procedure employed preserves the ability of the ribosomes to synthesize protein. Samples of identical size, taken from cytosolic as well as from membrane‐bound ribosomes isolated from the same source, behaved similarly in vitro: they were both active, their activity was arrested by ribonnuclease and, as shown by aurintricarboxylic acid treatment, most of their mRNA molecules were complexed with the ribosomes. Variation in translation capacities seemed to depend on the season and physiological stage of the bud tissue.