I have several 2-year grafts of slow growing dwarf conifers. Is it possible to temporarily overwrite genetic dwarfism using growth stimulants? Would like to accelerate the vegetative growth for a few years until they reach respectable sizes and then let them return to their slow inherent growth rates. I have been considering to apply gibberellic acid-either by foliar sprays or injections-late in the next dormant period or after the start of growth next spring. Would gibberellic acid be a suitable hormone or will auxins, abscisic acid, cytokinins work better in conifers. How about combinations of different hormones? GA3 appears to be generally recognized as a growth hormone that accelerates shoot growth. GA3 applications also include germinating seeds, breaking dormancy in plants, or to induce flowering and cone production. GA3 at concentrations of up to 200 ppm is reported to generally promote formation of male flowers, concentrations of 200 to 300 ppm promote female flowers, and concentrations above 600 ppm are to suppress initiation of any flowers. However, I am not able to find any references to the increase of vegetative growth specifically in connifers. Would appreciate any guidance. The following papers could be leads. But I cannot access them electronicly or through our public library system. Could anyone share electronic copies? 1. Wang, W., C. H. A. Little, et al. (1997). Control of longitudinal and cambial growth by gibberellins and indole-3-acetic acid in current-year shoots of Pinus sylvestris. Tree Physiology 17(11): 715-721. (a) Dep. Silvic., Swed. Univ. Agric. Sci., S-901 83 Umea, Sweden 2. Wang, Q., C. H. A. Little, et al. (1995). Effect of laterally applied gibberellin A4/7 on cambial growth and the level of indole-3-acetic acid in Pinus sylvestris shoots. Physiologia Plantarum 95(2): 187-194. (a) Dep. Silviculture, Swed. Univ. Agric. Sci., S-901 83 Umea, Sweden 3. Wang, Q., C. H. A. Little, et al. (1992). Effect of exogenous gibberellin A-4/7 on tracheid production, longitudinal growth and the levels of indole-3-acetic acid and gibberellins A-4, A-7 and A-9 in the terminal shoot of Pinus sylvestris seedlings. Physiologia Plantarum 86(2): 202-208. (a) Dep. Silviculture, Swed. Univ. Agric. Sci., S-901 83 Umea, Sweden Thank you... Chris
Hello Chris, While I have access to at least one of the journal articles via online access through UBC, I'm obliged to respect the usage license negotiated by the university (i.e., I can't do what you've requested). Your public library might be able to tap into one of the university library systems and retrieve the journal issue or the journal article for you at a lower cost than what might be requested for a single article through the publisher. Another alternative, of course, is to visit a university library, if one is accessible. They usually have at least a few public access workstations from which you can then read the article online. If not, I've always found the university librarians (at UBC) to be exceptionally helpful.
Hi Daniel: I am glad you addressed this issue. I felt it was out of place for anyone to ask for such information when they are not a member of the UBC forum. Who do we end up helping and what is their "angle" for wanting the information? A technical discussion on the issue and effects of growth regulators is fine with me but the better information on the subject is not online and we will have people citing online references that will not know the subject well enough to "see through" the procedural errors and in some cases haphazard lab summated reports. A good book on physiology and differentiation in plants such as one by P.F. Wareing in England on the subject may be more helpful than what we may see online for better understanding the basics of growth regulators. People still do not know how to equate that lab study results differ greatly than applied practice will in the field or in the nursery. Jim
