70 Percival and Fraser: Sugars to Improve Root Growth and Transplant Success stimulatory effects of sugars on root regeneration. Conse- quently, the higher root growth potential values associated with sugar applied to birch may reduce drought-related transplant shock symptoms permitting increased shoot and leaf growth recorded at 24. Work elsewhere has shown that exogenously applied auxins (a plant hormone involved in root metabolism) promote root initiation and increase numbers and length of existing roots of a range of plants by 6- to 18-fold in some instances (Looney and McIntosh 1968; Struve and Moser 1984; Struve 1990); however, a delay exists between each process, with each requiring a different optimum auxin concentration. The concentration for growth tends to be lower than that for initiation (Kelly and Moser 1983). Results of this investigation indicated a sugar concentration of at least 25 g/L (3.4 oz/gal) is required before significant effects on root formation occur. By week 24, significant effects on root length were recorded. Consequently, a sugar concentration of at least 25 g/L (3.4 oz/gal) is initially optimal for root formation such that, with time, dilution by watering or degradation in the soil possibly resulted in a concentration inducing elongation of existing roots. In conclusion, applications of sugars improved root and shoot growth and reduced transplant losses in birch; however, further studies are required to understand the mechanistic basis by which this occurred and to determine whether sugars can provide useful soil amendments for landscape- sized trees greater than 50 mm (2 in.) diameter. Likewise, the practicality of applying sugars at weekly intervals for the first month commencing budbreak needs to be addressed. This is an area worthy of further research given the fact that sugars are water soluble, nontoxic, environmentally safe, and inexpensive to purchase. Acknowledgments. The author is grateful for funding from the TREE Fund (Hyland Johns grant program). LITERATURE CITED Bingham, I.J., and E.A. Stevenson. 1993. Control of root growth: Effects of carbohydrates on the extension, branching and rate of respiration of different fractions of wheat roots. Physiol. Plantarum 88:149–158. Bingham, I.J., J.M. Blackwood, and E.A. Stevenson. 1997. Site, scale and time course adjustments in lateral root initiation in wheat following changes in C and N supply. Ann. Bot. 80:97–106. ———. 1998. Relationship between tissue sugar content, phloem import and lateral root initiation in wheat. Physiol. Plantarum 103:107–113. ©2005 International Society of Arboriculture Blunden, G., and Woods, D.L. 1969. Effect of carbohydrates in seaweed fertilizers, pp 647–653. In Proceedings of the 6th International Seaweed Symposium. Finnie, J.F., and van Staden, J. 1985. The effect of seaweed concentrate and applied hormones on in vitro cultured tomato roots. J. Plant. Physiol. 120:215–222. Gilbertson, P., and A.D. Bradshaw. 1990. The survival of newly planted trees in inner cities. Arboric. J. 14:287–309. Haase, D.L., and R. Rose. 1993. Soil moisture stress induces transplant shock in stored and unstored 2+0 Douglas-fir seedlings of varying root volumes. For. Sci. 39:275–294. Johnston, M., and B.S. Rushton. 1999. A Survey of Urban Forestry in Britain. University of Ulster, Coleraine, UK. Kelly, R J., and B.C. Moser. 1983. Root regeneration of Liriodendron tulipifera in response to auxin, stem pruning, and environmental conditions. J. Am. Soc. Hortic. Sci. 108:1085–1090. Koch, K. 1996. Carbohydrate modulated gene expression in plants. Annu. Rev. Plant. Physiol. 47:509–540. Lichtenthaler, H.K. 1987. Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes. Methods Enzymol. 148:350–382. Lindqvist, H., and H. Asp. 2002. Effects of lifting date and storage time on changes in carbohydrate content and photosynthetic efficiency in three deciduous species. J. Hortic. Sci. Biotechnol. 77(3):346–354. Looney, N.E., and D.L. McIntosh. 1968. Stimulation of pear rooting by preplant treatment of nursery stock with indole-3-butyric acid. Proc. Am. Soc. Hortic. Soc. 92:150–154. Martin, T., H. Hellmann, R. Schmidt, L. Willmitzer, and W.B. Frommer. 1997. Identification of mutants in metabolically regulated gene expression. Plant J. 11(1):53–62. Meinander, O., S. Somersalo, T. Holopainen, and R.J. Strasser. 1996. Scots pine after exposure to elevated ozone and carbon dioxide probed by reflectance spectra and chlorophyll a fluorescence transients. J. Plant Physiol. 148:229–236. Pattison, D. 1994. Morphological changes induced in Phytophthora cinnamomi Rands by extract of Ascophyllum nodosum and effects on soilborne microbial populations. Ph.D. thesis. The University of Strathclyde in association with Scottish Agricultural College (SAC), UK. Percival, G.C., M.S. Karim, and G.R. Dixon. 1998. The influence of light enhanced glycoalkaloids on resistance to Fusarium sulphureum and F. solani var. coeruleum in potato. Plant Pathol. 47:665–670. Percival, G.C., and J. Gerritsen. 1998. The influence of plant growth regulators on root and shoot growth of containerised trees following root removal. J. Hortic. Sci. Biol. 73(3):353–359. Salisbury, F.B., and C.W. Ross. 1985. Plant Physiology (3rd ed.). Wadsworth, Belmont, CA.
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