Studies of acid-soluble phosphorus compounds in genetically pure lines of Avena fatua with different dormancy characteristics

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Abstract
Seven genetically pure lines of wild oat selections of known dormancy characteristics were grown under uniform field conditions. Acid-soluble phosphorus components were determined in the dry seeds, in the imbibed seeds, and in imbibed seeds with dormancy-breaking treatments. No significant correlation between dormancy level and acid-soluble phosphorus composition was established for any component other than inorganic phosphorus (Pi). In dry caryopses Pi varied from 5 to 10% of the acid-soluble fraction. A highly significant inverse correlation was found between levels of Pi in the dry caryopsis and the relative depth of dormancy of the wild oat selection considered. The effect of imbibition on Pi level varied with depth of dormancy. Intact seeds of nondormant lines imbibed for 52 h showed a significant decline in Pi prior to coleorhiza protrusion from the dehulled caryopsis. More deeply dormant lines of Avena fatua (pure lines Anderson 51, Anderson 474, or Crop Science 40) required up to 10 days of incubation for significant drops in Pi to appear, while the most dormant lines (pure line Montana 73 and Idaho) did not evidence significant decline in Pi even after 10 days of incubation. The increase in Pi level associated with coleorhiza protrusion could be produced in the imbibed dormant lines by piercing them with a fine needle, by treating with gibberellic acid (GA3), or by a combination of the two treatments. The combination of piercing and GA3 treatment was much more effective than either treatment alone.