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

[摘要] 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.

[学科分类] 农业科学（综合）