Accumulation of Ethanol in Ice-encased Winter Cereals1
- C. J. Andrews2
Ice cover at the soil surface is frequently damaging to winter cereals in northern areas, even at mild subfreezing soil temperautres under snow. In controlled environments, winter cereal plants were rapidly damaged during ice encasement at −1 C, and exposure periods giving 50% kill ranked in accordance with cold hardiness of the cultivars. These exposure periods varied from 7.8 days for ‘Puma’ winter rye (Secale cereale L.) to 3.4 days for ‘Dover’ winter barley (Hordeum vulgare L. emend) with intermediate values for ‘Kharkov’, ‘Frederick’ and ‘Cappelle Desprez’ winter wheat (Triticum aestivum L. em Thell). Seedlings encased in ice accumulated ethanol, which increased to higher levels in cultivars more resistant to ice. Much of the ethanol produced in the plant leached into the surrounding water during thawing. The total production by the plant was about 0.5% of the fresh weight after 7 days encasement. This concentration was the same as that from isolated crowns. In the hardier cultivars, production of ethanol by isolated crowns was similar during supercooled immersion, or ice encasement at −1 C. Crowns of winter cereal cultivars differed in their tolerance to exogenous ethanol. At the interpolated LD50 concentration due to exogenous ethanol, the internal content of ethanol was at least three times its concentration at the LD50, duration due to ice, indicating that ethanol is not the only damaging factor in ice encasement.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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