Abstract
Endogenous, free indol-3yl-acetic acid (IAA) levels were measured in the main stem in the 10-year-old cambial zone, in the adjoining differentiating xylem, and in the adjoining mature xylem of 15–20-year-old Pinus contorta Dougl. by single-ion-current monitoring, combined gas chromatography — mass spectrometry, on several dates from early spring to early winter. Microscopy was used to determine the state of cambial activity on each harvest date. The IAA levels were found to be nearly constant at 1 μg g-1 DW in the cambial zone from March to July, then to increase to near 2 μg g-1 DW during the remainder of the growth season. No clear correlation was evident between number of fusiform cells per radial file and IAA content in the cambial zone. By contrast, the IAA content in differentiating xylem was higher than that in the adjoining meristematic zone on all harvest dates and also exhibited marked seasonal variation, peaking near 16 μg g-1 DW in mid summer, and declining to 1 μg g-1 DW in autumn. In mature xylem, IAA levels were very low and showed negligible variation. The fresh weight to dry weight ratio of differentiating xylem was greater than that of the cambial zone, and greater in the cambial zone than in mature xylem.
References
Bandurski, R.S. (1980) Homeostatic control of concentrations of indole-3-acetic acid. In: Plant growth substances 1979, p. 527, Skoog, F., ed. Springer, Berlin Heidelberg New York
Denne, M.P., and Wilson, J.E. (1977) Some quantitative effects of indoleacetic acid on the wood production and tracheid dimensions of Picea. Planta 134, 123–128
Horgan, R. (1981) Modern methods for plant hormone analysis. Progr. Phytochem. 7, 137–170
Lee, T.T. (1980) Effects of phenolic substances on metabolism of exogenous indole-3-acetic acid in maize stems. Physiol. Plant. 50, 107–112
Lee, T.T. (1977) Role of phenolic inhibitors in peroxidase-mediated degradation of indole-3-acetic acid. Plant Physiol. 52, 372–375
Masuda, Y. (1980) Auxin-induced changes in noncellulosic polysaccharides of cell walls of monocot coleoptiles and dicot stems. In: Plant growth substances 1979, p. 527, Skoog, F., ed. Springer, Berlin Heidelberg New York
Morris, D.A. (1977) Transport of exogenous auxin in two-branched pea seedlings. (Pisum sativum L.). Planta 136, 91–86
Odani, K. (1974) Indoleacetic acid oxidase in cambial zone of Pinus densiflora Sieb. et Zucc. J. Jpn. Wood Res. Soc. 20, 512–515
Pengelly, W.L., Bandurski, R.S. (1981) Longitudinal distribution of indole-3-acetic acid in the cortex and vascular stele of the dark-grown Zea mays mesocotyl. Plant Physiol. 67s, 5i
Sabnis, D.D., Hirshberg, G., Jacobs, W.P. (1969) Radioautographic analysis of the distribution of label from 3H-indoleacetic acid supplied to isolated Coleus internodes. Plant Physiol. 44, 27–36
Savidge, R.A. (1981) Regulation of seasonal cambial activity and tracheid differentiation in Pinus contorta Dougl. PhD Diss. Univ. Coll. Wales, Aberystwyth, Dyfed, United Kingdom
Savidge, R.A., Wareing, P.F. (1981a) A tracheid-differentiation factor from pine needles. Planta 153, 395–404
Savidge, R.A., Wareing, P.F. (1981b) Plant growth regulators and the differentiation of vascular elements. In: Xylem cell development, pp. 192–235, Barnett, J.R., ed. Castle House Publ., London
Savidge, R.A., Wareing, P.F. (1982) Apparent auxin production and transport during winter in the non-growing pine tree. Can. J. Bot. 60, 681–691
Sheldrake, A.R. (1971) Auxin in the cambium and its differentiating derivatives. J. Exp. Bot. 22, 735–740
Wilson, B.F., Wodzicki, T.J., Zahner, R. (1966) Differentiation of cambial derivatives: proposed terminology. For. Sci. 12, 438–440
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Savidge, R.A., Heald, J.K. & Wareing, P.F. Non-uniform distribution and seasonal variation of endogenous indol-3yl-acetic acid in the cambial region of Pinus contorta Dougl.. Planta 155, 89–92 (1982). https://doi.org/10.1007/BF00402937
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DOI: https://doi.org/10.1007/BF00402937