[en] Shoots of the hybrid walnut Juglans nigra x Juglans regia contained serotonin in the micromole range and indole-3-acetic acid (IAA) in the nanomole range. The serotonin level fell by 40 % in 12 h in auxin (IBA) treated whole shoots and then reincreased to a maximum (50 % over the control) after 36 h. The same pattern was followed in the top portions of the shoot but in the shoot bases, serotonin always remained under the control level. The early decrease of serotonin was correlated with an increase in IAA-aspartate. The early decrease and peaking of the serotonin level preceded and corresponded to the increase and peaking of free IAA in the shoot bases. The initial serotonin pool in treated-to-root shoots might thus suffice for the biosynthesis of IAA and IAA-conjugated compounds. Because of its auxin-like properties, the early serotonin peak might be taken into consideration as an endogenous auxin signal for rooting in the present material. If this turns out to be so, the rooting signal for the shoot bases necessarily should come from the apices.
Bandurski, R.S., Cohen, J.D., Slovin, J.P., Reinecke, D.M., Auxin biosynthesis and metabolism (1995) Plant Hormones. Physiology, Biochemistry and Molecular Biology, pp. 39-65. , Davies, P.J. (ed.): Kluwer Academic Publishers, Dordrecht - Boston - London
Berthon, J.Y., Maldiney, R., Sotta, B., Gaspar, T., Boyer, N., Endogenous levels of plant hormones during the course of adventitious rooting in cuttings of Sequoiadendron giganteum in vitro (1989) Biochem. Physiol. Pflanz., 184, pp. 405-412
Blakesley, D., Auxin metabolism and adventitious root initiation (1994) Biology of Adventitious Root Formation, pp. 143-154. , Davis, T.D., Haissig, B. (ed.): Plenum Press, New York
Blakesley, D., Weston, G.D., Hall, J.F., The role of endogenous auxin in root initiation. Part I: Evidence from studies on auxin application and analysis of endogenous levels (1991) Plant Growth Regul., 10, pp. 341-353
Duroux, L., (1993) Rôle de l'Acide Indole-3-acétique et de la 5-hydroxytryptamine Endogènes Au Cours de l'Initiation des Racines Adventives Chez Le Noyer (Jugions sp.), , Rapport de D.E.A., Université de Nancy I - INRA, Orléans
Driver, J.A., Kuniyuki, A.H., In vitro propagation of Paradox walnut rootstock (1984) HortScience, 19, pp. 507-509
Engström, K., Lundgren, L., Bioassay-guided isolation of serotonin from fruits of Solanum tuberosum (1992) Acta Pharm. Nord., 4, pp. 91-92
Gaspar, T., Kevers, C., Hausman, J.F., Ripetti, V., Peroxidase activity and endogenous free auxin during adventitious root formation (1994) Physiology, Growth and Development of Plants in Culture, pp. 289-298. , Lumsden, P.J., Nicholas, J.R., Davies, W.J. (ed.): Kluwer Academic Publishers, Dordrecht - Boston - London
Gruselle, R., Nicaise, C., Boxus, P., Regulation of in vitro shoot multiplication in Persian walnut by different carbon sources and by ammonium phosphate (1995) Bull. Rech. Agron. Gembloux, 30, pp. 47-53
Hausman, J.F., Changes in peroxidase activity, auxin level and ethylene production during root formation by poplar shoots raised in vitro (1993) Plant Growth Regul., 13, pp. 263-268
Heloir, M.C., Kevers, C., Hausman, J.F., Gaspar, T., Changes in the concentrations of auxins and polyamines during rooting of in vitro propagated walnut shoots (1996) Tree Physiol., 16, pp. 515-519
Jay-Allemand, C., Capelli, P., Cornu, D., Root development of in vitro hybrid walnut microcuttings in a vermiculite containing gelrite medium (1992) Scientia Hort., 51, pp. 335-342
Moncousin, C., Rooting of in vitro cuttings (1991) Biotechnology in Agriculture and Forestry 17. High-Tech and Micropropagation I, pp. 231-261. , Bajaj, Y.P.S. (ed.): Springer-Verlag, Berlin - Heidelberg - New York - London - Paris - Tokyo - Hong Kong - Barcelona - Budapest
Moncousin, C., Favre, J.M., Caspar, T., Early changes in auxin and ethylene production in vine cuttings before adventitious rooting (1989) Plant Cell Tissue Organ Cult., 19, pp. 235-242
Norcini, J.G., Heuser, C.W., Hamilton, R.H., Changes in free and conjugated indole-3-acetic acid during initiation and early development of adventitious roots in mung bean (1985) J. Amer. Soc. Hort. Sci., 110, pp. 528-533
Nordström, A.C., Eliasson, L., Levels of endogenous indole-3-acetic acid and indole-3-acetylaspartic acid during adventitious root formation in pea cuttings (1991) Physiol. Plant., 82, pp. 599-605
Nordström, A.C., Jacobs, F.A., Eliasson, L., Effect of exogenous indole-3-acetic acid and indole-3-butyric acid on internal levels of the respective auxins and their conjugation with aspartic acid during adventitious root formation in pea cuttings (1991) Plant Physiol., 96, pp. 856-861
Pilet, P.E., Action auxinique comparée de la tryptamine et de la sérotonine (1964) Pharm. Acta Helvet., 39, pp. 313-326
Regula, I., Koslevska-Pletikapic, B., Krsnik-Rasol, M., Presence of serotonin in Juglans ailanthifolia Carr. and its physiological effects in plants (1989) Acta Bot. Croat., 48, pp. 57-62
Ripetti, V., Kevers, C., Gaspar, T., Two successive media for the rooting of walnut shoots in vitro. Changes in peroxidase activity and in ethylene production (1994) Adv. Hort. Sci., 8, pp. 29-32
Umrath, K., Thaler, I., Auslösung von Blattbewegungen bei Mimosa und von Krümungen von Lupinus-Hypocotylen, gedentet durch Freisetzung von Erregungssubstanz und Auxin (1981) Phyton, 20, pp. 333-348. , Austria