scholarly journals 194 Effects of Chemical Growth Retardants on Rooting and Stem Elongation in Propagation of Stachytarpheta spp.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 475E-475
Author(s):  
Richard K. Schoellhorn ◽  
A.J. Compton
Keyword(s):  
Root Development ◽  
Stem Elongation ◽  
Dry Weight ◽  
Shoot Elongation ◽  
Chemical Effect ◽  
Growth Retardants ◽  
Chlormequat Chloride ◽  
Chloride Water ◽  
Vigorous Plant ◽  
Extensive Breeding

Plants, which move directly from the wild into commercial propagation, without the benefit of extensive breeding and selection, often pose production-oriented problems for growers. Vigorous plant growth, especially during the propagation phase of production is a common problem. The purpose of this work was to determine the degree of efficacy offered by chemical control of stem elongation in propagation of Porter Weed [Stachytarpheta mutabilis, S. mutabilis var. violacea, and S. urticifolia]. Tip cuttings of three Stachytarpheta species were given a 10-s dip in the following treatment solutions: daminozide (2500 and 5000 mg·L-1), daminozide and chlormequat chloride tank mix (2000 mg·L-1 ea.), paclobutrazol (2 and 4 mg·L-1), uniconazole (2 and 4 mg·L-1), distilled water, and undipped controls. Cuttings were then treated with a 0.1% IBA rooting powder and placed under intermittent mist on the propagation bench. After 2 weeks in propagation, cuttings were harvested and shoot elongation, root development, and dry weights were evaluated. The interaction of chemical and species was significant for stem elongation and dry weight; chemical effect on root development was also significant. Paclobutrazol and uniconazole offered greater control of stem elongation than daminozide, daminozide-chlormequat chloride, water, or control treatments.

scholarly journals Pink Polka-Dot Plant (Hypoestes phyllostachya) Response to Growth Retardants

1992 ◽  
Vol 10 (2) ◽  
pp. 87-90
Author(s):  
James T. Foley ◽  
Gary J. Keever
Keyword(s):  
Foliar Spray ◽  
Shoot Elongation ◽  
Growth Retardants ◽  
Chlormequat Chloride ◽  
Spray Applications

Abstract Pink polka-dot plant, Hypoestes phyllostachya Bak., was treated with one or two foliar spray applications of Bonzi (paclobutrazol) (25, 50, or 100 ppm), Cycocel (chlormequat chloride) (3500 ppm) or B-Nine (daminozide) (3500 ppm) to suppress shoot elongation. One or two applications of 3500 ppm Cycocel (chlormequat chloride) retarded shoot elongation, resulting in consistently mounded plants. Bonzi (paclobutrazol) and B-Nine (daminozide) also suppressed shoot elongation but to a lesser degree, and plants were not uniform.

scholarly journals Early Flurprimidol Drench Applications Suppress Final Height of Four Poinsettia Cultivars

2011 ◽  
Vol 21 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Christopher J. Currey ◽  
Roberto G. Lopez
Keyword(s):  
Stem Elongation ◽  
Final Height ◽  
Foliar Spray ◽  
Euphorbia Pulcherrima ◽  
Growth Retardants ◽  
Height Ratio ◽  
Chlormequat Chloride ◽  
Area Index ◽  
Aesthetic Appearance ◽  
Plant Growth Retardants

Plant growth retardants (PGRs) are commonly applied to control poinsettia (Euphorbia pulcherrima) stem elongation to meet a target final height. Two weeks after pinching, 4-fl·oz substrate drenches containing 0.0, 0.05, 0.10, 0.15, 0.20, or 0.25 mg·L−1 flurprimidol were applied to high-vigor ‘Orion’ and low-vigor ‘Polly Pink’ poinsettia (Expt. I); while drenches containing 0.0, 0.05, 0.10, or 0.15 mg·L−1 flurprimidol or a foliar spray containing 1250 mg·L−1 daminozide and 750 mg·L−1 chlormequat chloride were applied to high-vigor ‘Classic Red’ and low-vigor ‘Freedom Salmon’ poinsettia (Expt. II). Final height of ‘Orion’ and ‘Polly's Pink’ poinsettia was suppressed by 12% to 25% and 13% to 30%, respectively, as flurprimidol concentration increased from 0.05 to 0.25 mg·L−1. Final height of ‘Classic Red’ and ‘Freedom Salmon’ was suppressed by 11% to 30% and 10% to 19%, respectively, as flurprimidol concentration increased from 0.05 to 0.15 mg·L−1. Although the daminozide and chlormequat chloride spray had no significant effect on bract area index compared with untreated plants, bract area index was smaller for all plants treated with flurprimidol. However, the bract area to height ratio of all cultivars was not impacted by any PGR application, indicating aesthetic appearance was not negatively affected with smaller bract area. Time to anthesis was delayed by up to 4 days when 0.10 mg·L−1 was applied to ‘Classic Red’, although no significant delays were observed for the remaining cultivars. Based on these results, flurprimidol may be applied as an early drench to suppress height of poinsettia without adversely impacting finished plant quality or crop timing.

scholarly journals Effect of Plant Growth Retardants on Stem Elongation of Hibiscus Species

2003 ◽  
Vol 13 (2) ◽  
pp. 293-296 ◽  
Author(s):  
Ryan M. Warner ◽  
John E. Erwin
Keyword(s):  
Plant Growth ◽  
Stem Elongation ◽  
Stem Length ◽  
Growth Retardants ◽  
Chlormequat Chloride ◽  
Plant Growth Retardants ◽  
Butanedioic Acid ◽  
Spray Applications

One-time spray applications [about 6 mL (0.2 fl oz)] of chlormequat chloride [1000 or 2000 mg·L-1 (ppm)], daminozide (2500 or 5000 mg·L-1), paclobutrazol (20 or 40 mg·L-1) and uniconazole (5 or 10 mg·L-1) varied in efficacy in reducing Hibiscus coccineus (Medic.) Walt., H. radiatus Cav., and H. trionum L. (flower-of-an-hour) stem elongation. Chlormequat chloride inhibited stem elongation of all species, with a 2000 mg·L-1 application reducing stem length of H. coccineus, H. radiatus, and H. trionum by 87%, 42%, and 52%, respectively, compared to untreated plants, 28 d after application. Paclobutrazol also inhibited stem elongation of all species. Uniconazole reduced stem elongation of H. coccineus and H. radiatus, but not H. trionum. Daminozide applied at 5000 mg·L-1 reduced H. radiatus stem elongation only. Growth retardants examined in this study did not delay flowering of H. trionum, the only species that flowered during the experiment. (Chemical names used: ancymidol (α-cyclopropyl-α-(4-methoxyphenol)-5-pyrimidinemethonol), chlormequat chloride(2-chloroethyltrimethylammonium chloride), paclobutrazol ((+)-(R*,R*)-beta((4-chlorophenyl)methyl)-alpha-(1,1-dimethyl)-1H-1,2,4-triazol-1-ethanol), daminozide ([butanedioic acid mono(2,2-dimethylhydrazide)], uniconazol-P ((E)-(+)-(s)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pent-1-ene-3-ol)).

scholarly journals Use of Growth Retardants to Promote Flowering of Mountain Laurel, Kalmia latifolia L.

1999 ◽  
Vol 17 (1) ◽  
pp. 11-17
Author(s):  
Thomas J. Banko ◽  
Richard E. Bir
Keyword(s):  
Growth Inhibition ◽  
Stem Elongation ◽  
Shoot Elongation ◽  
Flower Initiation ◽  
Moderate Increase ◽  
Growth Retardants ◽  
Kalmia Latifolia ◽  
Second Growth ◽  
Compact Growth ◽  
Mountain Laurel

Abstract Spray treatments of the growth retardants A-Rest (ancymidol at 0, 53, 106 ppm), Bonzi (paclobutrazol at 0, 10, 50, 100, 200, 400, 600 ppm) and Sumagic (uniconazole at 0, 10, 25, 50, 75, 100, 200, 300 ppm) were applied to container-grown Mountain laurel (Kalmia latifolia L.) to evaluate their effectiveness for promotion of flower initiation and inhibition of shoot elongation. A-Rest had no effect on flower initiation at the concentrations tested. Bonzi promoted a moderate increase in inflorescences on one cultivar evaluated. Uniconazole sprays of 50 ppm or higher increased inflorescence numbers of most cultivars tested. Application in the spring to plants two years from propagation gave the most consistent results, however, with some cultivars, applications following the second growth flush as late as early August promoted flower initiation. Uniconazole treatments also reduced stem elongation resulting in more compact growth. Stem elongation was retarded with increasing concentrations of uniconazole for the growth flush in the spring in the year following treatment. The results of this study show that Sumagic (uniconazole) in the range of 50 to 75 ppm increases inflorescence numbers without excessive growth inhibition when applied in the spring to most cultivars two years from propagation.

scholarly journals Growth Retardants Affect Landscape Performance of Zinnia, Impatiens, and Marigold

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 557-560 ◽  
Author(s):  
Joyce G. Latimer
Keyword(s):  
Weight Gain ◽  
Plant Height ◽  
Stem Elongation ◽  
Dry Weight ◽  
Plant Quality ◽  
Subjective Rating ◽  
Growth Retardants ◽  
Shoot Dry Weight ◽  
Landscape Performance ◽  
Bedding Plant

Various spray rates of paclobutrazol, 5000 ppm daminozide, 200 ppm ancymidol, or drought imposition (visible wilt symptoms for up to 2 hours daily) were applied to three bedding plant species to determine effects on growth in the greenhouse and the subsequent growth and performance of treated plants in the landscape. Seedlings of Zinnia efegans Jacq. `Peter Pan Scarlet' responded to all growth retardants (paclobutrazol at 40 and 90 ppm) and the drought treatment in the greenhouse. However, zinnias treated with paclobutrazol or ancymidol still exhibited reductions in plant height 5 and 7 weeks after transplanting to the landscape, and in plant quality (subjective rating of plant appearance with emphasis on flower cover) at 5 weeks after transplanting. Daminozide or drought controlled zinnia growth in the greenhouse but had no carry-over effect in the landscape. Stem elongation of Impatiens wallerana Hook `Accent Red' seedlings was moderately controlled by 20 ppm paclobutrazol in the greenhouse. There were no other treatment effects in the greenhouse. Paclobutrazol (20 ppm) reduced final plant height and quality (7 weeks postplanting). Treatment with daminozide or drought reduced plant width and quality after 5 and 7 weeks in the landscape. Ancymidol had no effect on landscape performance of impatiens. Shoot dry weight gain and stem elongation of Tagetes erects L. `Papaya Crush' seedlings were reduced by ancymidol or 40 ppm paclobutrazol in the greenhouse. Shoot dry weight gain of marigold seedlings was inhibited during the first week of landscape establishment by prior treatment with daminozide, ancymidol, or drought. Final plant height and width in the landscape were not affected by any treatment; however, 40 ppm paclobutrazol, daminozide, or ancymidol decreased final plant quality. Chemical names used: α -cyclopropylα -(4-methoxyphenyl) -5-pyrimidinemethanol (ancymidol); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); β -[(4-chlorophenyl) methyl] - β - (1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

scholarly journals Paclobutrazol or Ancymidol Effects on Postharvest Performance of Potted Ornamental Plants and Plugs

HortScience ◽  
2015 ◽  
Vol 50 (9) ◽  
pp. 1370-1374 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Brian E. Whipker ◽  
John M. Dole
Keyword(s):  
Plant Growth ◽  
Shelf Life ◽  
Stem Elongation ◽  
Ornamental Plants ◽  
Growth Control ◽  
Foliar Spray ◽  
Dry Weight ◽  
Growth Retardants ◽  
Potted Plants ◽  
Plant Growth Retardants

Effects of paclobutrazol and ancymidol on postharvest performance and growth control of potted sunflower (Helianthus annuus L.), zinnia (Zinnia elegans Jacq.) and marigold (Tagetes erecta L.), petunia (Petunia ×hybrida Vilm.) plugs, respectively, were studied. Paclobutrazol was applied as a drench at 0, 1.0, 2.0, or 4.0 mg of a.i. per 15.2-cm pot for sunflower and 0, 0.5, 1.0, or 2.0 mg per 12.5-cm pot for zinnia, while ancymidol was applied at 0, 40, 80, and 160 mg·L−1 with a volume of 0.21 L·m−2 as a foliar spray for marigolds or petunia plug crops. With an increase in paclobutrazol dose or ancymidol concentration, plant growth (plant height and diameter, shoot fresh or dry weight) was controlled for all species tested. Use of 1.0–2.0 mg paclobutrazol per pot produced 21% to 28% shorter plants with 12% to 15% smaller plant diameter, 13% to 19% less shoot fresh weight, 15% to 21% less dry weight, and darker green foliage color for potted sunflower than nontreated plants. Treatment with 1.0–4.0 mg paclobutrazol per pot delayed first wilting by 0.7–1.4 days compared with nontreated plants. For zinnia, 0.5–1.0 mg paclobutrazol controlled plant growth, produced dark green foliage, and extended shelf life by delaying first wilting by 2.6–3.9 days and second wilting by 1.4–2.0 days than nontreated plants. For marigold and petunia plugs, 40–80 mg·L−1 ancymidol provided ample growth control with darker green foliage; however, postharvest longevity was extended only when plugs were sprayed with 160 mg·L−1 ancymidol. During simulated storage and shipping, plant growth retardants maintained darker green foliage for potted sunflower, zinnia, and marigold plugs and prevented postharvest stem elongation of petunia plugs. In summary, use of plant growth retardants effectively controlled excessive plant growth and extended shelf life of potted plants and plugs.

scholarly journals MECHANICAL CONDITIONING OF GREENHOUSE-GROWN TRANSPLANTS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 616a-616
Author(s):  
Joyce G. Latimer
Keyword(s):  
Weight Gain ◽  
Plant Growth ◽  
Large Scale ◽  
Stem Elongation ◽  
Dry Weight ◽  
Growth Retardants ◽  
Mechanical Conditioning ◽  
Shoot Dry Weight ◽  
Growth Increase ◽  
Postharvest Handling

Since chemical growth retardants are no longer labelled for use on vegetable transplants, mechanical conditioning provides an alternative method of controlling excessive stem elongation under greenhouse conditions. Mechanical conditioning includes brushing or shaking treatments that physically impact or displace the plant and generally reduce plant growth, increase stem and petiole strength, and improve overall plant quality. The resulting transplants have less breakage during postharvest handling, may be more stress tolerant, and are faster to establish in the field. However, only minor effects on crop yield have been identified. Brushing reduced broccoli transplant size, but improved shoot dry weight gain during field establishment but had no effect on head yield. Brushing is a labor intensive practice for large-scale operations. Current attempts to mechanize brushing require that the plants are uniform in height and treatment tolerant. Additional research in non-contact treatments like shaking or vibration of benches is necessary. The effects of the treatments on stress tolerance and predisposition to disease need to be clarified.

Growth and Branching Responses of Portulaca grandiflora to Foliar Applications of Chemical Growth Regulators

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447c-447
Author(s):  
T.J. Banko ◽  
M.A. Stefani
Keyword(s):  
Growth Regulators ◽  
Growth Habit ◽  
Stem Elongation ◽  
Block Design ◽  
Shoot Elongation ◽  
Main Shoot ◽  
Randomized Complete Block Design ◽  
Portulaca Grandiflora ◽  
Prostrate Growth ◽  
Secondary Shoot

During container production of portulaca, growth of long, prostrate, sparsely branched stems makes handling of plants difficult, and reduces their commercial appeal. Growers prefer to minimize shoot elongation while increasing branching to provide a full, compact plant. The objectives of this study were to evaluate growth regulators for promotion of branching and inhibition of stem elongation. Container-grown plants ≈21 cm in diameter were treated with sprays of ProShear (benzylaminopurine) at 62.4, 125, and 250 ppm; Promalin (benzyaminopurine + gibberellins 4+7) at 125, 250, and 500 ppm; Atrimmec (dikegulac) at 250, 500, and 750 ppm; and Florel (ethephon) at 250, 500, and 750 ppm. These treatments were compared with untreated controls in a randomized complete-block design. Main shoot lengths were measured at 16, 31, and 51 days after treatment (DAT). Numbers of new shoot breaks were counted 16 DAT. The growth habit, that is, tendency to grow upright or prostrate, was also evaluated 16 DAT. The most-effective material for retarding primary shoot elongation and for stimulating secondary shoot development was ProShear. At 16 DAT, 250 ppm ProShear reduced shoot elongation by 25% compared to control plants. This treatment also increased the number of secondary shoot breaks by 143%. Promalin increased the number of new shoot breaks, but it also increased the lengths of all shoots. High rates of Florel and Promalin caused shoots to grow predominantly upright rather then prostrate. ProShear, however, caused more prostrate growth as rate increased.

Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Stem Elongation ◽  
Tree Height ◽  
Shoot Elongation ◽  
Main Stem ◽  
Tree Age ◽  
Precommercial Thinning ◽  
Two Factors ◽  
Artificial Inoculations

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

scholarly journals Effect of Propagation Tray Design on Early Stage Root Development of Acer rubrum, Quercus rubra, and Populus tremuloides 1

2017 ◽  
Vol 35 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Darby McGrath ◽  
Jason Henry ◽  
Ryan Munroe ◽  
Erin Agro
Keyword(s):  
Populus Tremuloides ◽  
Root Development ◽  
Root Architecture ◽  
Quercus Rubra ◽  
Early Stage ◽  
Acer Rubrum ◽  
Dry Weight ◽  
Red Oak ◽  
Quaking Aspen ◽  
Red Maple

Abstract This experiment investigated the effect of different plug-tray cell designs on root development of red maple (Acer rubrum), red oak (Quercus rubra), and quaking aspen (Populus tremuloides) seedlings. In April of 2015, seeds of each species were sown into three plug trays with different substrate volumes and grown for 17 weeks. Two trays had permeable walls for air-pruning, one with vertical ribs and one without. The third tray had impermeable plastic cell walls. Harvested seedlings were analyzed for root dry weight, length, volume, surface area and number of deflected roots. Root length per volume was highest in the impermeable-walled tray for red maple and quaking aspen. The total numbers of deflected root systems were higher for all species in the impermeable-walled tray. Seedlings grown in the air-pruning trays had smaller proportions of deflected root masses. Greater substrate volume did not influence root deflection development. The air-pruning tray without vertical ribs had the lowest total number of root masses with misdirected roots and lower proportions of root masses with misdirected roots for all species. These results indicate that improved root architecture in root-air pruning tray designs is achievable in tree propagation; however, vertical plastic structures in air-pruning trays can still cause root deflections. Index words: Deflected roots, air-pruning, seedling, propagation, plugs, root architecture. Species used in the study: red maple (Acer rubrum L.); red oak (Quercus rubra L.); quaking aspen (Populus tremuloides Michx.).

Sign in / Sign up

Export Citation Format

Share Document