Phosphorus-containing Compounds at Comparable Germination Stages of Caryopses of Avena Species

A number of the phosphorus transformations accompanying imbibitionand initial germination in caryopses of wild oats (A vena fatuaL.) differ in nature and kind from those accompanying seedlingdevelopment. Even in non-dormant lines of wild oat germinationis extended and seedling development uneven. The significanceof early phosphorus transformations can be obscured. Proceduresto synchronize germination stages were developed by (i) usingseeds which had been exposed to room temperature for extendedperiods of dry storage, (ii) inducing germination of imbibedseeds by dehulling, piercing and/or gibberellin A3 treatments,or (iii) constructing artificial seed groupings of known germinationpercentage by appropriate selection of seeds from an unevenlygerminating seed source. All three procedures were effectivein identifying those processes associated with initial germination.The best synchronization was obtained with method (i). Germination,in contrast to imbibition, was signalled by a significant dropin inorganic phosphate levels, followed by a later rise as seedreserves of phytate were mobilized for seedling development.Differences in the rates of mobilization of acid-soluble phosphoruscompounds were apparent between cultivated oats and geneticallynon-dormant wild oats. Key words: Avena sp, Phosphorus compounds, Seeds, Germination