Effects of Oxygen and Temperature During Imbibition on Seeds of Two Bean Lines at Two Moisture Levels

Abstract

Low temperature and oxygen stresses were imposed during the first 48 hr of germination on 2 lines of snap bean (Phaseolus vulgaris L.), stress tolerant (PI-165426-BS) and stress-sensitive (‘Goldcrop’). At 22°C, O2 concentrations of 0%, 1%, and 2% increased leakage from the seeds, delayed emergence, and reduced growth, compared to 5% and 21% O2. These effects were aggravated by reducing the initial seed moisture from 12% to 8% in ‘Goldcrop’, but not in PI-165426-BS. At 10°, the effect of oxygen deficiency was minimized. Low temperatures inhibited growth of ‘Goldcrop’, but not of PI-165426-BS, and increased leakage from seeds of both lines. The survival of seeds exposed to the low temperature decreased when initial seed moisture was reduced from 12% to 8%. Flooding the seeds for 24 hr increased leakage and reduced emergence and growth much more than 24 hr of complete anoxia. Since the effects of anoxia are different than flooding injury, a mechanism of flooding injury not related to oxygen deficiency is discussed.