APOPTOSIS IN CELLS OF THE INITIAL LEAF AND COLEOPTILE OF WHEAT SEEDLINGS - INTERNUCLEOSOMAL FRAGMENTATION OF GENOME AND SYNTHESIS OF HEAVY OLIGONUCLEOSOME-SIZE DNA FRAGMENTS

Apoptosis-specific oligonucleosome-size nDNA fragmentation(180+/-10 bp )(n), n greater than or equal to 1 and intensive incorporation of labe led precursors into the ''heavy'' (rho=1.716 g/cm(3)) DNA fraction wer e detected in the leaf and coleoptile regions of wheat seedling compri sed of non-dividing cells. The distribution pattern of labeled DNA(195 +/-10 bp)(n), n greater than or equal to 1 in agarose electrophoresis imitates the oligonucleiosomal DNA fragments formed during the apoptoi c internucleosomal breakdown of nDNA. Thus, in cells of the initial le af and coleoptile, growth and development of normal wheat seedlings ev en during early ontogenesis stages are accompanied by apoptosis-specif ic internucleosomal DNA fragmentation and intensive synthesis of ''hea vy'' GC-enriched oligonucleosome-size DNA fragments.