( Baldwin et al., 2012 ; Dant et al., 2005 ; Flessner et al., 2014 ; Hart et al., 2005 ) with little published data regarding possible benefits of glyphosate applications, in particular, growth regulation. Although glyphosate is considered a class D PGR
Christian M. Baldwin, A. Douglas Brede, and Jami J. Mayer
Susan L. Steinberg, Jayne M. Zajicek, and Marshall J. McFarland
43 ORAL SESSION (Abstr. 438-444) WOODY PLANT GROWTH REGULATION
J. Michael Goatley Jr., Victor L. Maddox, and Robert M. Watkins
Research was conducted over 2 years to evaluate efficacy of various levels and combinations of imazaquin and AC 263,222 for growth regulation of unimproved bahiagrass (`Pensacola') turf. Imazaquin at 0.42 kg·ha–1 caused only slight bahiagrass discoloration in all trials and reduced seedhead count (as compared to the nontreated control) by ≥80% for 8 weeks after treatment (WAT) following a July 1992 application. AC 263,222 at 0.042 or 0.056 kg·ha–1 applied in late May or June provided 100% seedhead control through 8 WAT. However, AC 263,222 applied in July 1992 and Aug. 1993 at 0.056 kg·ha–1 resulted in unacceptable discoloration through 8 WAT. AC 263,222 at 0.014 or 0.028 kg·ha–1 provided ≥90% seedhead control with only minimal discoloration following applications in July or Aug. 1993, indicating that lower rates of AC 263,222 provided acceptable seedhead control of bahiagrass during times when growth was slowed due to moisture stress. Chemical names used: (±)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid (AC 263,222); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin).
Chung-Liang Chang and Ming-Fong Sie
influence plant growth height and growth time, even without considering the generic characteristics of the plant itself. To simplify analysis and facilitate the design of the growth regulation system, this study divided the plant growth process into stages
Suxiao Hao, Yanfen Lu, Jing Liu, Yufen Bu, Qi Chen, Nan Ma, Zhiqin Zhou, and Yuncong Yao
are crucial for the growth regulation of dwarf ‘SH6’ apple rootstock seedlings. Fig. 5. Analysis of the transcript levels of genes related to gibberellin (GA) biosynthesis under different treatment [GA and paclobutrazol (PAC)] conditions. ( A – D ) The
Pamela J. Paulsen and David Hensley
Landscape maintenance in Hawaii occurs year round. Many popular groundcovers are pruned monthly, some twice monthly. This increases labor costs and creates large amounts of waste. Several rates of five commercial growth regulators (cimectacarb, flurprimidol, mefluidide, paclobutrazol, and uniconazole) were applied to several groundcovers commonly grown in Hawaii. Species used include Cuphea hyssopifolia, Evolvulus glomeratus, Lantana montevidensis, Myoporum spp., and Wedelia trilobata. Studies were conducted in the shadehouse with potted plants and in the field with established plants. Rates, response, and method of application (spray or soil drench) for each product were evaluated. Growth, length of control, and phytotoxicity were measured. Flurprimidol, paclobutrazol, and uniconazole showed the greatest control for the most species. Flurprimidol and paclobutrazol controlled growth for the longest time, up to 4 months for some species. However, these materials resulted in the greatest amount of damage, even at low rates. Cimectacarb controlled growth of fewer species, while mefluidide caused the least growth reduction for all species.
Susan L. Steinberg, Jayne M. Zajicek, and Marshall J. McFarland
Growth of potted hibiscus (Hibiscus rosa-sinensis L.) was limited either by pruning or by a soil drench of `uniconazole at 3.0 mg a.i. per pot. Both treatments changed the water use of hibiscus. Five days after treatment with uniconazole, plants showed reduced water use, an effect that became more pronounced with time. Water use of pruned plants was reduced immediately after pruning, but soon returned to the level of the control due to the rapid regeneration of leaf area. Pruned or chemically treated plants used 6% and 33% less water, respectively, than the control. Chemically treated plants had a smaller leaf area, and individual leaves had lower stomatal density, conductance, and transpiration rate than control plants. Under well-watered conditions, the sap flow rate in the main trunk of control or pruned plants was 120 to 160 g·h-1·m-2, nearly three times higher than the 40 to 70 g·h-1·m-2 measured in chemically treated plants. Liquid flow conductance through the main trunk or stem was slightly higher in chemically treated plants due to higher values of leaf water potential for a given sap flow rate. The capacitance per unit volume of individual leaves appeared to be lower in chemically treated than in control plants. There was also a trend toward lower water-use efficiency in uniconazole-treated plants. Chemical name used: (E)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-l-yl)-1-penten-3-ol (uniconazole).
Joyce G. Latimer
`Jupiter' or `Marengo' pepper (Capsicum annuum L.) seedlings maintained under 0%, 30%, 50%, or 80% shade in a greenhouse were brushed 80 strokes twice daily beginning at the cotyledonary, first true leaf, or second true leaf stage. Averaged across shade environments, brushing reduced `Jupiter' and `Marengo' stem length 25% to 36% and 6% to 28%, respectively. However, the percentage of plants exhibiting mechanical damage by brushing ranged from 86% to 93% and 48% to 90% for `Jupiter' and `Marengo', respectively. Transplant quality tended to decrease as brushing was delayed. When brushing of `Marengo' was reduced to 40 strokes twice daily in 1992, plant growth reduction decreased, but the percent damage was about the same. The damage severity, however, was reduced as indicated by higher plant-quality ratings. Pepper plant damage was excessive for the small amount of growth regulation provided by brushing.
Aneta K. Studzinska, David S. Gardner, James D. Metzger, David Shetlar, Robert Harriman, and T. Karl Danneberger
action of the new growth retardant CGA 163’935 (cimectacarb), p. 818–827. In: Karssen, C.M., L.C. van Loon, and D. Vreugedenhil (eds.). Progress in plant growth regulation. Kluwer Academic, Dordrecht, The Netherlands. Agharkar, M. Lomba, P. Altpeter, F
Michelle L. Bell, James R. Baker, and Douglas A. Bailey
Potential phytotoxicity and plant growth-regulating activity of insecticidal dips for poinsettias was investigated by dipping, then growing unpinched, rooted cuttings of `Red Sails', `Freedom', and `V-14 Glory' in the following insecticidal emulsions for five durations: 2% insecticidal soap (Safer's), 2% horticultural oil (Sunspray Ultrafine), fluvalinate (Mavrik Aquaflow), oxythioquinox (Joust), kinoprene (EnstarII), azadirachtin (Margosan-O), fenoxycarb (Precision), and an oil-carrier formulation of Beauveria bassiana (Naturalis-L). Dips in soap, oxythioquinox, Naturalis-L, and oil were phytotoxic to all three cultivars. Also, kinoprene and fenoxycarb were phytotoxic to `Red Sails'. At dip durations of 10 s and greater, soap, Naturalis-L, and oil were phytotoxic. Oxythioquinox was phytotoxic at durations of 1 min, 15 min, and 1 h. Only fluvalinate was not phytotoxic as a 4-h dip. After 2 weeks, plants dipped in oxythioquinox, Naturalis-L, and oil were stunted. By week 4, differential cultivar effects were seen: six dips (all but fluvalinate and azadirachtin) stunted growth of `Red Sails', whereas only Naturalis-L and oil retarded growth of `V-14 Glory'. Six weeks after treatment, growth of all cultivars was stunted by oxythioquinox, Naturalis-L, and oil, but was not retarded by fluvalinate or azadirachtin. Dip duration significantly affected growth by weeks 4 and 6, when all durations of Naturalis-L and oil reduced growth. Additionally, 4-h dips of oxythioquinox and kinoprene stunted plants after 4 weeks, and 1- and 4-h dips of oxythioquinox, kinoprene, and fenoxycarb adversely affected growth after 6 weeks.