Growth retardation of woody species by three growth regulators

Abstract

Greenhouse grown 1-to 2-year-old seedlings of silver maple (Acer saccharinum L.), American sycamore (Platanus occidentalis L .), black locust (Robinia pseudoacacia L .), and white ash (Fraxinus americana L .) were injected with one of three plant growth regulating chemicals . 1-napthylacetic acid (NAA) and NN,N-tributyl-N-(trifluormethylbenzyl) ammonium chloride (an analogue of Phosfon S, coded DOWCO 391) retarded shoot regrowth at appropriate concentrations without causing an unacceptable degree of foliar damage to seedlings . Fosamine-ammonium (ammonium ethyl carbanoyl phosphonate, trade name Krenite) even at low concentrations, produced severe phytotoxicity indicating that it acts more as a herbicide than as a growth retardant .

Naphthaleneacetic Acid Reduces Leader Growth of Fraser Fir Christmas Trees

“…Naturally occurring auxins such as indoleacetic acid are involved in shoot elongation, cell division, flower formation, and inhibition of root growth (Bandurksi and Nonhebel, 1984). Applying synthetic NAA during the growing period can reduce leader growth and the number of shoots (Bir and Ranney, 1992;Boswell et al, 1976;Domir and Wuertz, 1982;Wilson, 1983). When under stress because of high levels of auxins, ethylene production may be stimulated (Kefeli and Kalevitch, 2003).…”

“…Ethylene is a naturally produced hormone that causes inactivation of auxins, leaf abscission, and growth inhibition (Kefeli and Kalevitch, 2003). At high levels, NAA can reduce growth and cause injury or death to plants (Boswell et al, 1976;Domir and Wuertz, 1982;Hare, 1982;Kramer and Kozlowski, 1979;Wilson, 1983). Therefore, objectives of this research were to 1) determine the effect of SS-RTU on leader growth of fraser fir; and 2) compare two methods of application.…”