The sorghum embryo in relation to the hydrolysis of the endosperm during germination and seedling growth

Time‐course changes in the structural and physiological properties of sorghum grain embryo have been investigated in relation to the hydrolysis of the endosperm during germination and seedling growth. Histochemical analysis showed that the reserve food materials of the scutellum tissue were metabolised rapidly during germination and seedling growth. Light microscope analysis of structural changes showed that scutellar epithelial cell elongation was associated with endosperm reserve mobilisation. Electron microscope studies verified preliminary histochemical and light microscope findings and showed that extensive metabolism of subcellular storage materials occurred during early germination and seedling growth. Physiological evidence indicated that both sorghum embryo and endosperm were insensitive to the gibberellic acid, GA 3 . Other hormones such as indole‐3‐acetic acid and kinetin also failed to induce α‐amylase production. This suggests that the hormonal response of the aleurone of sorghum is different from that of barley aleurone. Dissection of sorghum showed that the whole body of the scutellum was capable of producing α‐amylase.