SPECIFIC FEATURES OF SYNAPTONEMAL COMPLEX ES FORMATION IN SY-7 AND SY-10 DESYNAPTIC MUTANTS OF RYE

The preparations of microsporocytes spread on a hypotonic medium were examined with electron microscope in prophase I of meiosis in two grou ps of desynaptic mutants of diploid winter rye. Both groups are charac terized by the presence in metaphase I of univalents and by partial st erility. At the stage of zygotene in these mutants synapsis of homolog ous and non-homologous chromosomes starts with the formation of synapt onemal complexes (SC). At pachytene, synapsis is completed and multiva lents are formed. The lateral SC elements can fold into the <<hairpin> > structures upon their self-synapsis. Breaks were often observed at p airing partners switch points of the multivalents and at the bottom of <<hairpins>>. Such disturbances in the pairing of homologous chromoso mes in desynaptic mutants of diploid plants were found for the first t ime.