Effects of cytokinin on adventitious root formation in callus cultures of Vigna unguiculata (L.) Walp

• Published in: In vitro cellular & developmental biology. Plant Vol. 34; no. 3; pp. 189 - 195
• Main Authors: Soh, W.Y. (Chonbuk National University, Chonju, Korea.), Choi, P.S, Cho, D.Y
• Format: Journal Article
• Language: English
• Published: Wallingford Society for In Vitro Biology 01.07.1998; Cambridge University Press
• Subjects: 2,4-D; ADVENTITIOUS ROOTS; Auxins; Biological and medical sciences; Biotechnology; CALLUS; CULTURE MEDIA; Cultured cells; Cytokinins; DARKNESS; Developmental Biology/Morphogenesis; Establishment of new cell lines, improvement of cultural methods, mass culture; Eukaryotic cell cultures; EXPLANTS; Fundamental and applied biological sciences. Psychology; HYPOCOTYLS; KINETIN; Korean culture; LEAVES; Methods. Procedures. Technologies; MICROPROPAGATION; MORPHOGENESIS; NAA; PLANT ANATOMY; Plant cells and fungal cells; Plant roots; Plant tissues; Plants; ROOTING; TISSUE CULTURE; VIGNA UNGUICULATA; Culture medium; Callus; 2,4-D; Root; Rhizogenesis; Vigna unguiculata; Micropropagation; Cytokinin; Grain legume; Adventitia; Leguminosae; Dicotyledones; Angiospermae; Alkanoic acid; Plant growth substance; Kinetin; Spermatophyta; Phytohormone; Aryloxyacetic acids
• ISSN: 1054-5476; 1475-2689
• DOI: 10.1007/BF02822707

Yellowish compact callus, induced from cowpea hypocotyls on Murashige and Skoog (MS) medium (1962) containing 0.2 mg/l(0.93 μM) kinetin and 0.4 mg/l (1.81 μM) 2,4-dichlorophenoxyacetic acid (2,4-D), was subcultured on MS medium containing cytokinin alone, auxin alone, or auxins plus cytokinins in order to determine the effect of cytokinins on root organogenesis in callus cultures. The callus actively proliferated on the same medium but did not show any organogenic activity macroscopically as well as microscopically. On medium with N⁶-benzyladenine (BA) and 1-naphthaleneacetic acid (NAA), the yellowish compact callus first changed to pale green compact callus and then many green spots appeared on its surface under light culture. But the yellowish compact callus remained yellowish and white spots appeared on its surface in dark culture. These spots gradually became white nodular structures. Adventitious root formation from the nodular structures occurred not only on the same medium, but also on medium with either auxin or cytokinin but not both. Yellowish compact callus on medium with auxin alone was transformed to yellowish friable callus, which did not develop adventitious roots. The yellowish friable callus could gain rhizogenic activity only after morphological modification to pale green compact callus on medium with auxin plus cytokinin. The modified callus did not form adventitious roots on medium with auxins but only with cytokinins. Therefore, it is suggested that cytokinins have stimulating effects on root formation from callus that previously did not show rhizogenic activity on medium with auxins alone. In addition, the rhizogenic potential of cowpea callus was discriminated from that of leaf explants, which formed adventitious roots directly on medium with auxin alone.