Metabolic Changes in Partially Dormant Wheat Seeds during Storage.

Changes in germination, seedling growth, respiration, response to applied gibberellic acid, and glucose-U-(14)C utilization were investigated in partially dormant wheat (Triticum aestivum L., Pa 151 x 107) seeds which were stored under various conditions for periods up to 1 year. Only seeds stored at -20 C and 12.4% moisture maintained partial dormancy, which was overcome by germinating in 10(-3)m gibberellic acid. Germination and seedling growth of seeds stored at 25 C and 15.1% moisture declined within 12 weeks and the percentage of seeds infected with storage fungi increased. Gibberellic acid produced faster growing seedlings, particularly from those seeds with partial dormancy, but did not overcome growth reduction which was caused by deterioration. Seeds kept under laboratory conditions (B), 25 C and 12.1% moisture (C), and 25 C and 15.1% moisture (D) for 12 weeks utilized 35, 55, and 80% less glucose, respectively, than those stored at -20 C and 12.4% moisture (A). Seeds stored under B and C consistently had higher germination, growth, and respiratory rates than seeds from A and D. The respiratory rate declined as deterioration advanced under D. Respiratory quotients ranged from 1.0 for seeds stored under A to 1.6 for seeds stored under D.