Effects of Gamma‐irradiation of Corn Seed on the Respiration and Growth of the Seedling

Abstract

The effect of presowing, gamma‐irradiation treatments on the growth and respiration of germinating corn was investigated. Exposures of 40 and 80 krads caused marked inhibition in seedling growth and inhibited the rate of respiration, measured as oxygen uptake per seedling. A decrease in respiration rates, at these doses, could be detected within 1 day after planting, well before emergence of the radicle. Lower doses which were not markedly growth‐inhibiting did not appear to inhibit respiration. A highly significant correlation was found between respiration rates at 1 day and shoot lengths of 3‐day‐old seedlings. The degree of correlation so measured was higher for shoots than for roots and was lowered by growth‐inhibiting doses of irradiation. The results indicate that rates of respiration during the first stages of germination may be an important factor in subsequent seedling growth and may provide the basis for predicting the growth of the shoot.