DNA synthesis and mitotic activity in germinating wheat seeds aged under various conditions

Wheat seed ageing and embryo protein degradation

“…These findings relate to the effect of ageing on the process of water uptake during early seed imbibition, where an extended lag-phase with little change in water uptake is responsible for a progressive delay in radicle emergence. Since it may be assumed that the intensity of expression of ageing symptoms is a result of a continuous, rather than a step, function (Ellis and Roberts, 1981;Dell'Aquila and Margiotta, 1986), the range of recorded germination periods and related biochemical variations would be proportionate to the degree of seed deterioration. Cumulative relationships between rates of radioactive methionine incorporation and corresponding times of completion of the lag phase of seed hydration and the onset of germination, respectively, in all aged seed samples (excluding 5%G seeds) are shown in Figure 2.…”

“…Two combinations of temperature and moisture content were used for accelerated seed ageing over 4 weeks of storage, as previously described (Dell'Aquila and Margiotta, 1986). Norba 1991) seeds had a 9.8% moisture content (FW basis) and 96% germination.…”

“…Norba 1991) seeds had a 9.8% moisture content (FW basis) and 96% germination. Two combinations of temperature and moisture content were used for accelerated seed ageing over 4 weeks of storage, as previously described (Dell'Aquila and Margiotta, 1986). Seeds (lOOg) were imbibed by soaking at 5°C for 20-30 min in sterile distilled water, then dried immediately for different lengths of time to reach the required moisture content (12.5% and 14.5%).…”

“…By the accelerated ageing technique, these factors have been variously combined to obtain seed lots having different degrees of vigour and to relate the physiological *Correspondence Abbreviations: smc = seed moisture content; 2-D PAGE = two-dimensional polyacrylamide gel eiectrophoresis; SDS = sodium dodecyl sulfate; kDa = kilodalton; MM = molecular mass. parameters of germination with biochemical indices of vigour (Woodstock, 1973;Halmer and Bewley, 1984;Dell'Aquila and Margiotta, 1986). Among the essential metabolic processes in early germination, protein synthesis in imbibing embryos represents a biosynthetic activity that correlates with the germination rate of wheat seed lots obtained by both ageing (Blowers et al, 1980) and the appropriate osmopriming technique (Dell'Aquila, 1987).…”