1955 Volume 68 Issue 810 Pages 363-368
1. Isolated cotyledons of Vigna sinensis were cultured on nutrient medium. When a part of the hypocotyl remained at the base of the cotyledon, the former grew out in a bulge, from which adventitious roots appeared.
2. When a cotyledon was cut at the base so as to remove entirely from the hypocotyl, the cut surface was covered by callus. In such a case, adventitious roots formed from the callus.
3. When a cotyledon was cut into apical and basal halves which are nearly equal in size, the cut surface of the apical pieces produced calluses and roots, while that of the basal pieces produced neither callus nor roots though they are formed at the opposite end.
4. Anatomical studies revealed that primordium of the adventitious root was differentiated from the parenchymatous cells of the phloem in the callus at the cut end of leaf vein.
5. It was discussed that the root formation might be influenced by the supply of hormone and other materials through the vein, and also by the amount of parenchymatous cells present in the phloem.
6. The number of arcs of the adventitious roots varied from four, a normal condition of the primary root, to two, intermediate conditions occurring also frequently.