These results demonstrate that most of the protein synthetic activity in embryos is associated with polysome structures, with only a relatively small fraction (7%) in monosomes (labeled as peak "1" in Fig.
The protocols employed in this study allowed for the reliable separation of polysomes from monosomes and the effective radioactive labeling with amino acids of nascent peptides still attached to polysomes (Fig.
A 5B chromosome nullisome of `Abbodanza' was selected as female (bridge) to cross with elite winter wheat cultivar Jing 411 (the genotype is 5[B.sup.Ph1Ph1]) and CS ph1b mutant (5[B.sup.ph1bph1b]), respectively; then, only the 5B chromosome monosomes
(5[B.sup.Ph1] and 5[B.sup.ph1b], the former can be obtained by crossing a bridge parent and Jing 411 every generation) were selected in the subsequent generations for further crossing; and finally, the SCAR marker was used at the seed or seedling stage to screen the 5B chromosome monosome
(5[B.sup.ph1b]) without waiting for flowering and meiotic analysis (in the present study the meiotic analysis was used only for checking the reliability of SCAR marker).