Developmental Anatomy of the Seedling of the Rice Plant

The embryo and the development of the seedling of the rice plant are described. 2. The general structural makeup and the provascular system of the rice embryo closely resemble that of the oat. 3. The primary root is the only seminal root present in the embryo. It is commonly a hexarch radial protostele, and lies approximately at a right angle to the axis of the epicotyl. It has three well defined histogens as commonly found among the Gramineae. 4. The root-stem transition of the vascular system takes place at the scutellar plate. 5. The scutellum is the cotyledon with a single cotyledonary (scutellar) bundle which branches only at its upper distal end. 6. The first internode contains four bundles. The relation of these bundles with those found at the second and higher nodes is described. 7. There is a meristematic region just below the second node. The activity of the cells in this region is responsible for the elongation of the first internode during germination. 8. The coleoptile is the second leaf. Its two vascular bundles have the same relation to the cotyledonary bundle as a pair of lateral bundles of the first foliage leaf. 9. There is no vascular tissue in the epiblast, ventral scale, and coleorhiza. 10. The development of the foliage leaves is described.