Abstract
The stability of [3H]zeatin riboside supplied to freshly excised tobacco pith explants was found to be inversely related to α-naphthaleneacetic acid concentration in the incubation medium. At higher concentrations of α-naphthaleneacetic acid greater breakdown of [3H]zeatin riboside was indicated by higher levels of degradative metabolites (adenine, adenosine and adenosine nucleotides) formed. This auxin effect on cytokinin metabolism appears to be mediated, at least in part, through cytokinin oxidase. The results of in-vitro assays carried out with partially purified enzyme from corn kernels substantiale this conclusion. These findings are discussed in relation to recent observations of auxin and cytokinin levels in crown-gall tumours with altered morphology.
Similar content being viewed by others
Abbreviations
- FPLC:
-
fast protein liquid chromatography
- HPLC:
-
high-performance liquid chromatography
- IP:
-
isopentenyladenine
- NAA:
-
naphthaleneacetic acid
- ZR:
-
zeatin riboside
References
Brownlee, B.G., Hall, R.H., Whitty, C.D. (1975) 3-Methyl-2-butenal: an enzymatic product of the cytokinin, N6-(Δ 2-isopentenyl) adenine. Can. J. Biochem. 53, 41–47
Binns, A.N., Labriola, J., Black, R.C. (1987) Initiation of auxin autonomy in Nicotiana glutinosa cells by the cytokinin-biosynthesis gene from Agrobacterium tumefaciens. Planta 171, 539–548
Hansen, C.E., Meins, F. Jr., Aebi, R. (1987) Hormonal regulation of zeatin riboside accumulation by cultured tobacco cells. Planta, in press
Hansen, C.E., Meins, F. Jr., Milani, A. (1985) Clonal and physiological variation in the cytokinin content of tobacco cell lines differing in cytokinin requirement and capacity for neoplastic growth. Differentiation 29, 1–6
Horgan, R. (1986) Cytokinin biosynthesis and metabolism. In: Plant growth substances 1985, pp. 92–98, Bopp, M., ed. Springer-Verlag, Heidelberg
Letham, D.S., Palni, L.M.S. (1983) The biosynthesis and metabolism of cytokinin. Annu. Rev. Plant Physiol. 34, 163–197
Letham, D.S., Palni, L.M.S., Tao, G.Q., Gollnow, B.I., Bates, C.M. (1983) The activity of cytokinin glucosides and alanine conjugates in cytokinin bioassays. J. Plant Growth Regul. 2, 103–115
McGaw, B.A., Horgan, R. (1983a) Cytokinin catabolism and cytokinin oxidase. Phytochemistry 22, 1103–1105
McGaw, B.A., Horgan, R. (1983b) Cytokinin oxidase from Zea mays kernels and Vinca rosea crown-gall tissue. Planta 159, 30–37
Morris, R.O., Akiyoshi, D.E., MacDonald, E.M.S., Morris, J.W., Regier, D.A., Zaerr, J.B. (1982) Cytokinin metabolism in relation to tumor induction by Agrobacterium tumefaciens. In: Plant growth substances 1982, pp. 175–183, Wareing, P.F., ed. Academic Press, London
Morris, R.O., Powell, G.K. (1987) Genes specifying cytokinin biosynthesis in prokaryotes. BioEssays 6, 23–28
Murashige, T., Skoog, F. (1962) A revised medium for rapid growth and bioessays with tobacco tissue cultures. Physiol. Plant. 15, 473–497
Palmer, M.V., Letham, D.S., Gunning, B.E.S. (1984) Cytokinin metabolism in non-dividing and auxin-induced dividing explants of Helianthus tuberosus L. tuber tissue. J. Plant Growth Regul. 2, 289–298
Palni, L.M.S., Horgan, R. (1983) Cytokinin biosynthesis in crown-gall tumour tissue of Vinca rosea: metabolism of isopentenyladenine. Phytochemistry 22, 1597–1601
Palni, L.M.S., Palmer, M.V., Letham, D.S. (1984) The stability and biological activity of cytokinin metabolites in soybean callus tissue. Planta 160, 242–249
Palni, L.M.S., Summons, R.E., Letham, D.S. (1983) Identification of the cytokinin complex of Datura innoxia, crown-gall tissue. Plant Physiol 72, 858–863
Parker, C.W., Entsch, B., Letham, D.S. (1986) Inhibitors of two enzymes which metabolise cytokinins. Phytochemistry 25, 303–310
Skoog, F., Miller, C.O. (1957) Chemical regulation of growth and organ formation in plant tissues cultured in vitro. Symp. Soc. Exp. Biol. 11, 118–131
Wareing, P.F. (1977) Growth substances and integration in the whole plant. Symp. Soc. Exp. Biol. 31, 337–365
Whitty, C.D., Hall, R.H. (1974) A cytokinin oxidase in Zea mays. Can. J. Biochem. 52, 789–799
Woolley, D.J., Wareing, P.F. (1972) Hormonal interaction, movement and metabolism of a cytokinin in rootless cuttings. New Phytol. 71, 781–793
Zhang, R., Letham, D.S., Wong, O.C., Nooden, L.D., Parker, C.W. (1987) The metabolism of 6-benzylaminopurine in soybean leaves and the inhibition of its conjugation. Plant Physiol. 83, 334–340
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Palni, L.M.S., Burch, L. & Horgan, R. The effect of auxin concentration on cytokinin stability and metabolism. Planta 174, 231–234 (1988). https://doi.org/10.1007/BF00394775
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00394775