Effect of osmotic stress on in vitro translational capacity of polysomes and on the composition of polysome-associated proteins in germinating seeds of pea (Pisum sativum L.)

Plant growth throughout the world is often limited by unfavourable environmental conditions. This paper reports results of a study on long- and short-term osmotic stress ( 0.5 MPa) followed by a recovery on in vitro translational capacity of polysomes and on the composition of polysome-associated proteins in germinating pea (Pisum sativum L.) seeds. Here we show that, under osmotic stress, cytoskeleton-bound polysomes were charaterized by the highest translation activity, which may be indicative of an important role that this population of polysomes plays in the synthesis of the so-called “stress proteins”. We also find out that in response to osmotic stress, new proteins (22.01, 96.47 and 105.3 kDa), absent in the unstressed sample, associated with the total pool of polysomes, whereas the protein of 22.95 kDa, which was present in the embryonic tissue of seeds germinating under unstressed conditions, disappeared. These changes may have affected both the stability and the translational capacity of polysomes.