Mitsugu Inoue

Bio: Mitsugu Inoue is an academic researcher. The author has contributed to research in topics: Callus & Auxin. The author has an hindex of 5, co-authored 9 publications receiving 116 citations.

Effect of Auxin Concentration on the Callus Induction from Various Organs of Rice Seedlings

Abstract: 1. Callus tissues were induced by various concentrations of 2, 4-dichlorophenoxyacetic acid (2, 4-D) from different organs, roots, mesocotyls, internodes, nodes, coleoptiles, leaf sheaths, and epidermal cells of scutellum of Oryza sativa and roots, leaves and stems of Echinochloa crus-galli, Nicotiana tabacum, and Vicia faba. 2. Callus induction is more remarkable in some organs of young rice seedlings than old ones with lower level of 2, 4-D. 3. Different concentrations of 2, 4-D are necessary for callus induction from different organs and diverse species. Tissues and organs in rice seeds, from which callus is able to be induced, are strikingly varied by different concentrations of auxin. 4. The concentration of auxin for callus induction is dependent on a sort of auxins used; IAA, NAA, or 2, 4-D. The difference of auxin concentration for the callus induction corresponds with the difference of auxin activity of the substances used. 5. Effect of kinetin on callus induction in rice seeds is not only undistinct but also repressive. 6. Thiamine is required for growth of rice cultures but it is not essential for callus induction in rice seeds. 7. It is discussed on the effects of the cutting of seedlings on callus induction in rice. 8. The tissues from which the callus is originated in various concentrations of 2, 4-D is histologically investigated on rice seeds and segments excised from the seedlings. Anatomical studies indicated that the initiation of callus in various organs resembled to the initiation of the adventitious root, except for epidermal cells of scutellum. 9. The organ differentiation in rice callus tissues is controled with various concentrations of 2, 4-D. Namely, callus tissues without root-like structures, callus tissues with root-like structures, abnormal roots and normal roots are formed as the concentration decreases.

High frequency plant regeneration from rice protoplasts by novel nurse culture methods

Abstract: Novel nurse culture methods have been developed for plant regeneration from protoplasts of rice (Oryza sativa). The nurse culture methods use the agarose-bead type culture in combination with actively growing nurse cells that are either in the liquid part of the culture or inside a culture plate insert placed in the centre of the dish. Protoplasts isolated from either primary seed calluses or suspension cultures of various callus origins, divided and formed colonies with a frequency of up to 10% depending on the protoplast source and the genotype. The presence of nurse cells was absolutely required for the induction of protoplast division. Plants were regenerated from protoplast-derived calluses of five tested cultivars with a frequency of 17%–50%. Close examination of the plant regeneration process suggested that plants are regenerated through somatic embryogenesis from protoplast-derived calluses. Over 300 protoplast-derived plants were transferred to either pots or the field and are being examined for karyotypic stability and various plant phenotypes.

Plant regeneration from protoplast-derived callus of rice (Oryza sativa L.).

Abstract: Protoplasts isolated from cultured rice cells of an A-58 cytoplasmic male sterile line (A-58 MS)(Oryza sativa L.) were used to investigate the regeneration of rice plants. A cultured cell line (T3) of A-58 MS with a high growth rate and dense cytoplasm was selected. About 10% of the protoplasts prepared from this established cell line plated in RY-2 (a new medium) formed colonies. The calli formed shoots and roots in the regeneration medium and developed into whole plants.

Long-duration, high-frequency plant regeneration from cereal tissue cultures

Abstract: By visual examination of calli derived from germinating seeds of wheat, oats, rice, proso millet, and pearl millet it has been possible to visually select embryogenic (E) callus which, on transfer to a regeneration medium, forms plants an average of 33 times more frequently than non-embryogenic (NE) callus of equal mass. Embryogenic callus consists of small isodiametric cells averaging 31 μm in diameter; NE callus consists of long tubular cells averaging 52 μm in width and 355 μm in length. Production of E callus is in many cases promoted by media containing 2,4-di- or 2,4,5-trichlorophenoxyacetic acid (2,4-D or 2,4,5-T) plus indole-3-acetic acid or tryptophan+kinetin. Production on NE callus is promoted by media containing 2,4-D or 2,4,5-T alone. As a result of initial experiments to optimize both media for E callus production and media for plant regeneration, callus derived in six passages from an average of 26 seeds could produce about 1,000 regenerated plants.

Transplant Production Systems

Abstract: In 1982 the new crops research program was initiated in the Florist and Nursery Crops Laboratory to increase the diversity of florist crop germplasm in the United States. Anigozanthos, Chamelaucium, Correa, a dwarf form of Eustoma grandiflorum 'Little Blue Belle', Chamelaucium, Cupressus, and other crops have been introduced to the industry with information that describes propagation, culture, and controlled flowering. Rooting of cutting or in vitro tissue culture propagation of new crops had included Achimenantha, Chamelaucium uncinatum, 'Purple Pride', and Eustoma grandiflorum, 'Little Belle Blue', Ornithogalum dubium, Lachenalia aloides, and Lilium. In addition, a new production technology using bulbils as propagules was developed for Lilium elegans, Asiatic hybrid lily. This production technology is discussed.

Establishment of a system of high-frequency embryogenesis from long-term cell suspension cultures of rice (Oryza sativa L.).

Abstract: Suspension cultures which maintained embryogenic potency for more than 18 months were established from excised immature embryos of rice (Oryza sativa L. cv. Konansou). The cultures were subcultured every three days in N6 medium supplemented with proline (10 mM), casein hydrolysate (300 mg/l), sucrose (30 g/l) and 2,4-D (1 mg/l). The frequency of embryogenesis from the embryogenetic suspension cultures reached about 90% when cell clusters (about 1 mm in diameter) were transferred to a solid medium which consisted of N6 medium, NAA (1 mg/l), kinetin (5 mg/l), sucrose (30 g/l) and Gelrite (2 g/l). When smaller clusters of cells (approximately 200–400 μm in diameter) were transferred to a liquid medium which consisted of salts of N6 medium diluted with an equal volume of water plus sucrose (45 g/l), NAA (0.01 mg/l) and 4-PU (0.1 mg/l) at a cell density of 13 clusters/ml in 2 ml of medium, somatic embryogenesis was initated at high frequency (about 50%). Morphological evidence is provided to demonstrate that the regeneration occurred via embryogenesis. This is the first report of high-frequency embryogenesis in suspension cultures of rice cells.