Deterioration of wheat seeds under subfreezing temperatures and related protein synthesis in germinating embryos
1995
Dell'Aquila, A. | Di Turi, M. (Germplasm Inst., Bari (Italy))
Wheat seeds (Triticum durum Desf. cv Venusia) were adjusted to moisture contents of 17.7, 20 and 23 % and kept at temperatures of 5, 40, -20, -50 and -80 deg C for 7 days. Seeds aged at 40 deg C were damaged progressively with increasing moisture content and storage time, but subfreezing temperature treatment caused loss of germination only in seeds containing 23 % moisture. Timing of germination onset, abnormal seedling percentage and seed leakage measurements confirmed that differential loss of vigour occurred under different combinations of storage factors. A decrease of 'in vivo' protein synthesis rate in imbibing embryos and quantitative changes of soluble methionine labelled proteins, synthesized during the radicle emergence phase, showed that normal protein synthesis patterns were differently impaired. Subfreezing temperatures prevented deterioration effects in embryos of 17.7 and 20 % moisture content. However, at a moisture content of 23 % marked changes in specific polypeptides occurred as the temperature was lowered from -20 to -80 deg C. The tolerance of seeds to storage under extreme environmental conditions could be monitored by certain 'germination specific' proteins, whose changes during the radicle emergence phase reflect the damaging of biosynthetic activities
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