イネカルスの発育と不定根形成過程の組織学的研究

抄録

The histological structure of compact and friable callus derived from rice seeds was observed. It was ascertained that the development of rice callus is of characteristic as follows. The development of the compact callus is composed of five phases. Phase 1: A clump of meristematic cells is formed. Phase 2: The clump differentiates into inner parenchyma and peripheral meristem. Phase 3: Sub-surface meristem appears along the inside of the peripheral meristem, and then parenchyma originated from the sub-surface meristem occurs far inward. Phase 4: The peripheral meristem turns into peripheral parenchyma. Phase 5: The cells of the sub-surface meristem vacuolate. A mass of the compact callus grows through the clump of meristematic cells occurring on the various positions of the callus. The development of the friable callus is composed of two phases. Phase 1: A clump intermixed with meristematic cells and parenchymatous cells is formed. Phase 2: The clump differentiates into inner parenchyma and peripheral meristem. The clump is either formed by the outgrowth of the sub-surface meristem in the compact callus or by the fragmentation of the peripheral meristem in the friable callus. Tracheary elements associated with cambial cells were observed scatteringly or as a mass in the compact callus, while few tracheary elements were observed in the friable callus. The peripheral region of the compact callus in phases 4 and 5 showed many structures resembling to root primordium. Therefore, the development of the compact callus would be considered as the early process of organization of the adventitious root.