Germination of Australian Channel Millet (Echinochloa turnerana (Domin) J.M. Black) Seeds. II. Effects of Anaerobic Conditions, Continuous Flooding, and Low Water Potential

Abstract

Channel millet seeds require a period of substantial wetting (as occurs during flooding) before mass germination is attained in its native environment, while the remainder of the life cycle often occurs under arid conditions. Imbibing seeds in solutions of mannitol or NaCl ranging from 0 to -1.5 MPa slowed germination and seedling growth but, after 14 days of imbibition in the light at 30°C germination was about 50% even at levels of moisture availability as low as -1.0 MPa. High germination percentages were also attained in the light inside flasks flushed continuously with humidified air, humidified N₂, or N₂ followed by air. Seeds failed to germinate in the dark under any of the above treatments, but did so to a certain extent when subsequently exposed to light. In the absence of O₂, seedlings were non-pigmented and without protruding radicles. Under conditions of continuous flooding in stagnant water to a depth of at least 10 cm, channel millet seeds germinated and produced plants which went on to flower within 3 months.