On the Three Types of Special Vascular Bundles of Coleoptile in Rice Plant

1. Three types of special vascular bundles were found in the rice coleoptile. The author has named them as short bundle, cortical bundle and separated bundle, respectively. 2. The separated bundle was found to diverge from the ordinary coleoptile bundle, but both the short and cortical bundles to be differentiated ad nouva from the cortical parenchyma near the coleoptilar node. 3. No morphological difberences were found between the cortical and the separated bundles, and their lengths were both a little shorter than that of the ordinary bundle. 4. All those special bundles were differentiated during the period of most rapid development of the embryo, but they were distinguishable with each other from the beginning of their appearance. 5. Frequency of appearance of the bundles was different from each other. As the coleoptile nervation increased, there differentiated first the short bundle, next the cortical bundle, and then the separated bundle. So the intensity of function of each bundle should be supposed to be increased in the similar order. 6. As seen from the variation in coleoptile nervation responding to environmental conditions, the appearance of the special vascular bundle in the coleoptile will be supposed to show control-action of coleoptile against the change of internal conditions of the embryo during its development.