Height Control of Picea spp. and Chamaecyparis lawsoniana with Uniconazole and 6-Benzyladenine

Abstract

The use of plant growth retardants (PGRs) could benefit conifer growers by enabling them to produce more uniform, live tabletop Christmas tree specimens. We applied two PGRs to determine effectiveness on height control and terminal bud density for the following species of conifer seedlings: Black Hills spruce (Picea glauca var. densata), Serbian spruce (P. omorika), Colorado blue spruce (P. pungens), and Port Orford cedar (Chamaecyparis lawsoniana). The chemicals were applied at 2-week intervals throughout an 8-week period for a total of four applications. Uniconazole was applied as a foliar spray and soil drench (5 and 1 ppm, respectively), 6-benzyladenine (BA) was applied as a foliar spray (500 and 1000 ppm), and the control did not receive a PGR application. Uniconazole was generally effective on the spruces but not on Port Orford cedar, whereas BA reduced height of all species and increased spruce bud densities. However, BA treatments were phytotoxic in all species tested. The drench of uniconazole caused minor phytotoxicity in Black Hills spruce, whereas foliar applications to Port Orford cedar had minor phytotoxic effects.

A Comparative Study of the Response of Fennel (Foeniculum vulgare, Mill) Plants from Egypt and China to Spraying with Benzyladenine (BA)

“…"This increment in vegetative parameters by using benzyladenine could be attributed to stimulatory effects of BA on cell division, cell elongation, shoot initiation and growth, nutrient mobilization, delay the processes of senescence and apical dominance alternation in plants" [24,25]. These results are in a similar pattern with those of Abdel-Rahman and Abdel-Kader [26] they observed that "foliar application of BA had a significant increase in plant height, number of branches/plant and plant dry weight.…”