Pre-emergence Flooding and Nitrogen Atmosphere Effects on Germinating Corn Inbreds
This investigation was conducted to assess the relationship between sensitivity to pre-emergence flooding and effects of anoxia on ethanol production and glycolytic activity in order to identify floodtolerant and flood-susceptible corn cultivars. Seed of 20 common corn inbred lines (Zea mays L.) were exposed to different durations (0, 6, 12, 24, 48, 96, 144 h) of simulated anaerobic conditions in the laboratory or, immediately after planting, to flooding in greenhouse and growth-chamber in two parts of bulk soil (glacial till parent materials) and one part sand. Percent seed germination and amount of produced ethanol, lactic acid, and dimethyl sulflde were determined after termination of anoxia in the laboratory; for greenhouse and growth-chamber experiments, percent seed germination was determined after termination of flooding. The results indicated that ethanol production was negatively correlated with seed viability. Inbred corn line DE811, tolerant of flooding, regulated glycolysis so that there was minimal production of ethanol; inbred corn line MO17, intolerant of flooding and associated anoxia, was unable to regulate glycolysis, as indicated by production of large quantities of ethanol as the major end product of glycolysis. Lactic accumulation under the N2 atmosphere was low and did not seem associated with seed viability. Dimethyl sulfide liberation was associated with the intolerant MO17. This S-containing volatile may be a product of seed metabolism, inasmuch as it occurs many metabolic changes as storage materials are hydrolyzed under anoxic conditions. Limitation of ethanol production may be the key to tolerance of low-O2 environments.
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