Dormancy in red rice. IV. Response of unimbibed and imbibing seeds to nitrogen dioxide

Publisher Website
Google Scholar
Abstract
Nitrogen dioxide at 4 to 8 ml 1−1 breaks dormancy of dehulled, unimbibed seeds of red rice (Oryza sativa L.) with minimum exposure times to the gas of 20 min or less. The response is independent of incubation medium pH following treatment. Germination is complete within 2 days but proceeds 4 to 6 h more slowly than non‐dormant controls. The magnitude of response at a constant NO2 dose is dependent upon initial seed moisture. There was less than 40% germination at 9.6% initial moisture while germination was 95% at 12% initial moisture. NO2 treatment also breaks dormancy of imbibing, dehulled seeds, but the response is dependent upon the pH of the medium. Dormancy is broken at pHs close to the pKa of nitrous acid. Intact, unimbibed or imbibing seeds respond to NO2 treatment only if partially dry‐afterripened prior to exposure.