بررسي برخي از عوامل موثر بر خفتگي بذر يولاف وحشي

An investigation on factors affecting seed dormancy in wild oats(Avena ludoviciana Durieu)

Wild oat (Avena ludoviciana Durieu.) is one of the important weeds in winter wheat. Seeds produced by this plant are viable in soil for a long time and germinate gradually. Physiological basis of wild oat seed dormancy was investigated. Results showed that complete germination of dormant seeds was obtained when the covering structures (glumels, pericarp, endosperm, aleurone layer) were removed. This shows that embryo may not be the main factor in dormancy and that it is non dormant. There are two factors that affect seed dormancy. The first is the presence of glumels that prevent seed germination mechanically and the second one is the aleurone layer in caryopsis . It causes dormancy by decreasing water potential in embryo .Using electrophoretic separation (SDS-PAGE), the protein composition of non dormant and dormant seeds were recognized. There were eight special polypeptide bands in dormant seeds, four of them had molecular weights of more than 66000 Da , and molecular weights of others were , 38695, 53380, 46505 and 20334 Da. However, in non dormant seeds 2 special polypeptide bands with molecular weights of 32197 and 25587 Da were observed. This may mean the presence of gene influence in seed dormancy and germination.