COLEORHIZA, ROOT AND COLEOPTILE EMERGENCE AND GROWTH: EFFECTS OF DIFFERENT WATER VOLUMES

The percentage of barley seeds (Hordeum vulgare) with coleorhiza or roots emerged at various times after germination in different volumes of water was determined. Germination was followed in barley seeds sown on filter papers moistened with 6–25 ml of water for up to 24 h at 25 °C; 30 seeds were sown on each 15-cm diameter petri plate. The most rapid germination, judged on coleorhiza emergence, occurred on 20 and 25 ml of water at 6 h, but root emergence was better on 9 than on 20 ml of water. Conditions appropriate for coleorhiza emergence retard root emergence. Similarly, at 45 h, coleoptile growth was better on 9 and 12 ml than on 20 ml of water. The initial stimulation of germination by 20 ml of water, succeeded by an inhibition of root and coleoptile growth, suggests that the various organs of a barley embryo respond differentially to different volumes of ambient water.