scholarly journals PINE BARK LEVELS AND PARTICLE SIZE INFLUENCE THE ACTIVITY OF PACLOBUTRAZOL AND UNICONAZOLE ON `FREEDOM' AND `GUTBIER' V-14 GLORY POINSETTIAS

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 737b-737
Author(s):  
Jesse R Quarrels ◽  
Steven E. Newman

A study was conducted to determine the effects of pine bark grind size and pine bark levels on the activity of two growth regulators on poinsettia Two bark grinds (≤ 6 mm and >10 mm) were used with four media combinations within each grind: vermiculite:bark:peat moss at 2:0:3, 2:1:2, 2:2:1, and 2:3:0 (by volume). Two growth regulators, paclobutrazol and uniconazole, were applied at 0, 0.125, and 0.250 mg/15 cm container in 250 ml water. Two poinsettia cultivars, `Freedom' and `Gutbier V-14 Glory', were planted September 2, 1993, pinched September 16, and growth regulators applied September 30. There were five single plant replications for each treatment. Stem length and bract area were effected by bark grind, bark level, growth regulator, and growth regulator rate. Plants treated with uniconazole had the shortest stems and the least bract area. Plants grown in the smaller grind and at higher bark levels were less effected. Plants treated with paclobutrazol had longer stems than those treated with uniconazole.

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 544a-544
Author(s):  
Jesse R. Quarrels ◽  
Steven E. Newman

A leaching frame was constructed to detect residual plant growth regulators in media. The table was 0.9 × 1.8 m and designed to hold 40 10-cm diameter by 30-cm PVC cylinders. Each cylinder was cut lengthwise in half and resealed with duct tape. Rooted cuttings of `Freedom' poinsettias were planted into each cylinder using two media combinations: 2 vermiculite: 2 peat moss: 1 pine bark and 2 vermiculite: 1 peat moss: 2 pine bark (by volume). Four growth regulator treatments were applied to the medium two weeks after transplanting: control, 0.25 mg paclobutrazol, 0.25 mg uniconazole, and 0.125 mg paclobutrazol applied as spike. After plant growth was recorded, the cylinders were removed and sliced lengthwise. Snapdragon plugs were then transplanted into the medium along the length of the cylinder to determine if any residual paclobutrazol remained. Paclobutrazol and uniconazole reduced stem length. The presence of pine bark in the media reduced the effect of the plant growth regulators.


1987 ◽  
Vol 1 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Rodney G. Lym ◽  
Neil E. Humburg

The effect of various growth regulators on seedling field bindweed (Convolvulus arvensisL. # CONAR) growth and control with herbicides was evaluated. Fourteen growth regulators were applied at 0.38 to 380 g/ha 7 days before herbicide application in greenhouse, growth chamber and field studies. Field bindweed seedlings pretreated with growth regulators were more effectively controlled by herbicides compared to those not pretreated in greenhouse evaluations. Abscisic acid [[R-(Z,E)]-(+)-5-(1-hydroxy-2,6-6-trimethyl-4-oxo-2-cyclohexane-1-yl)-3-methyl-2,4-pentadicenoic acid] (ABA), ancymidol [a-cyclopropyl-a-(p-methoxyphenyl)-5-pyrimidine methanol], cycloheximide {3-[2-(3,5-dimethyl-2-oxocylohexyl)-2-hydroxyethyl]glutarimide}, ethylenediamine tetraacetic acid [N,N′-1,2-ethanediyl-bis-(N-(carboxymethyl) glycine] (EDTA), and 1-naphthaleneacetic acid (NAA) increased field bindweed stem length. Ancymidol and gibberellic acid [ent-3α,10,13-trihydroxy-20-norgibberell-1,16-diene-7,19-dioc acid 19,10-lactone] (GA) increased root weight, and GA increased root length. Cycloheximide, ethephon [(2-chloroethyl)phosphonic acid] and MH (1,2-dihydro-3,6-pyridazinedione) decreased field bindweed root weight. Ancymidol, GA and IAA (indole-3-acetic acid) increased the number of shoots per plant of seedling field bindweed. Dicamba (3,6-dichloro-2-methoxybenzoic acid) efficacy was enhanced following field bindweed preconditioning with ethephon and IAA. Ancymidol and cycloheximide applied as pretreatments increased glyphosate [N-(phosphonomethyl)glycine] activity on seedling field bindweed. Ancymidol and IAA pretreatment improved field bindweed control with triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid}. Herbicide-growth regulator combination treatments that increased field bindweed control in greenhouse and growth chamber studies did not increase top growth control in the field.


1995 ◽  
Vol 22 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Wayne E. Mitchem ◽  
Alan C. York ◽  
Roger B. Batts

Abstract Chlorimuron was evaluated as a growth regulator on peanut. Treatments included chlorimuron at a total of 8.8 g ai/ha applied once at 60,75, or 90 d after emergence (DAE) or in equal portions applied twice at 60 and 75, 60 and 90, or 75 and 90 DAE or three times at 60, 75, and 90 DAE. Daminozide at 950 g ai/ha applied 75 DAE was included as a comparison. In a year with excessive vine growth, daminozide and all chlorimuron treatments except 8.8 g/ha applied 90 DAE reduced cotyledonary lateral branch and main stem length at harvest 9 to 20 and 12 to 24%, respectively, due to suppression of internode length. Sequential applications of chlorimuron generally suppressed growth more than single applications. No improvement in row visibility at harvest was noted. In a dry year with limited vegetative growth, neither chlorimuron nor daminozide affected cotyledonary lateral branch or main stem length at harvest. Chlorimuron at 2.9 g/ha applied 60, 75, and 90 DAE reduced yield 18% at one of four locations; no other treatment affected yield. Chlorimuron at 8.8 g/ha applied 60 DAE or 4.4 g/ha applied 60 and 75 DAE reduced the percentage of fancy pods and extra large kernels at one or more locations. No treatment affected the percentage of total sound mature kernels. Results suggest chlorimuron has little to no potential for use as a growth regulator.


2010 ◽  
Vol 3 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Matthew J. Rinella ◽  
Marshall R. Haferkamp ◽  
Robert A. Masters ◽  
Jennifer M. Muscha ◽  
Susan E. Bellows ◽  
...  

AbstractAuxinic herbicides, such as 2,4-D and dicamba, that act as plant growth regulators are commonly used for broadleaf weed control in cereal crops (e.g., wheat, barley), grasslands, and noncroplands. If applied at late growth stages, while cereals are developing reproductive parts, the herbicides can reduce seed production. We tested whether growth regulators have this same effect on the invasive annual grass Japanese brome. The herbicides 2,4-D, dicamba, and picloram were applied at typical field use rates to Japanese brome at various growth stages in a greenhouse. Picloram reduced seed production nearly 100% when applied at the internode elongation, boot, or heading stages of growth, whereas dicamba appeared to be slightly less effective and 2,4-D was much less effective. Our results indicate it may be possible to control Japanese brome by using growth regulator herbicides to reduce its seed production, thereby depleting its short-lived seed bank.


1984 ◽  
Vol 64 (2) ◽  
pp. 225-228 ◽  
Author(s):  
G. CACCO ◽  
G. DELL’AGNOLA

Auxin and cytokinin bioassays were performed to test the biological activity of soluble humic complexes (SHC). "Pea split stem curvature" (auxin test) and "cucumber" tests (cytokinin test) did not show any quantifiable biological activity of SHC. On the contrary, "cress test" and "senescence test" offered good evidence of a hormonal-like activity 100 times lower than that of IAA (10 mg IAA∙g−1 SHC) and 10 times lower than that of N6 BA (100 mg N6 BA∙g−1 SHC). At a high concentration of SHC, toxic effects were evident, indicating the presence of inhibitory substances which counteracted the hormone-like activity of humic complexes. Key words: Plant growth regulators, soluble humic complexes


Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 137-139 ◽  
Author(s):  
C. S. James ◽  
G. N. Prendeville ◽  
G. F. Warren ◽  
M. M. Schreiber

Interactions between carbamate and growth regulator herbicides were antagonistic both in whole plants and in plant segments. When combinations of isopropylm-chlorocarbanilate (chlorpropham) and (2,4-dichlorophenoxy)acetic acid (2,4-D) were applied to the foliage of either redroot pigweed (Amaranthus retroflexusL.) or pale smartweed (Polygonum lapathifoliumL.), the severe twisting effects of 2,4-D were greatly reduced. This interaction did not involve differential movement or metabolism of either herbicide. The induced elongation of soybean hypocotyl sections by the three growth regulators 2,4-D, 3,6-dichloro-o-anisic acid (dicamba), and 4-amino-3,5,6-trichloropicolinic acid (picloram) was inhibited in the presence of either chlorpropham orS-ethyl dipropylthiocarbamate (EPTC). Similarly, curvature tests using soybean (Glycine max(L.) Merr.) hypocotyl sections showed the curvature induced by the growth regulators to be almost completely eliminated by the presence of the carbamates.


2017 ◽  
Vol 2 (01) ◽  
pp. 24-27
Author(s):  
Reena Tomer ◽  
S. P. Singh ◽  
Varun Tomer ◽  
Mahesh Kumar ◽  
Nidhi Sharma

In the laboratory seedling were induced with nodule-like outgrowths using different growth regulators 2,4-D,IBA and NAA in nitrogen free Hoagland solution. Induced seedlings were inoculated with Azorhizobium caulinodans (ORS 571) in wheat variety C-306. One set was also raised as control. The treated paranoulated wheat seedlings were transferred to pot culture. The data was collected on 30, 60 and 90 days after sowing, which reveals that as a Azorhizobium caulinodans with 2,4-D treated plants shows maximum photosynthetic rate followed by NAA and IBA combinations. The biomass production was maximum in Azorhizobium caulinodans treated with 2,4-D followed by IBA and NAA.


2021 ◽  
Vol 39 (2) ◽  
pp. 62-67
Author(s):  
Sean J. Markovic ◽  
James E. Klett

Abstract Moroccan pincushion (Pterocephalus depressus) is a drought-tolerant perennial that is being used in landscapes throughout arid areas of the western United States. This paper describes two experiments researching vegetative cutting production from stock plants. Moroccan pincushion stock plants received foliar applications of gibberellic acid (GA3), benzyladenine, ethephon, or auxin [indole-3-butyric acid (IBA)] plant growth regulators (PGR). Plant growth regulators were applied singularly and in combination with GA3 to determine efficacy on stock plant growth. A propagation study was conducted simultaneously to determine effects of these different PGR treatments applied to stock plants on the rooting of moroccan pincushion cuttings. The stock plant study showed GA3 + benzyladenine application increased cutting production over other PGR treatments. Fresh weight of moroccan pincushion cuttings did not differ among treatments. While cuttings did not differ in dry weight in experiment 1, statistical differences were observed in experiment 2. However, these differences in dry weight did not affect the quality of the cuttings. Cuttings from stock plants treated with GA3 + IBA treatment had the highest numerical growth index [(height + width + width)/3]. Cuttings from stock plants treated with GA3 alone or in combination with another PGR were all greater in average growth index and statistically differed from those without GA3 being applied. PGR treatments did not affect rooting percentages of the cuttings with nontreated stock plant cuttings successfully rooting at an average rate of 95%. However, GA3 + IBA was the only treatment where cuttings had 100% rooting for both experiments, indicating potential rooting benefits. Index words: Plant growth regulator, propagation, Pterocephalus depressus, vegetative cuttings. Species used in this study: Moroccan pincushion [Pterocephalus depressus Archibald]. Chemicals used in this study: gibberellic acid (GA3), benzyladenine, ethephon, indole-3-butyric acid (IBA).


2017 ◽  
Vol 23 (1) ◽  
pp. 22 ◽  
Author(s):  
Fernanda Ludwig ◽  
Amaralina Celoto Guerrero ◽  
Guilherme Amaral Ferreira ◽  
Dirceu Maximino Fernandes ◽  
Roberto Lyra Villas Bôas

Periodic monitoring of the substrate solution allows the nutritional control of plants to be done more quickly and conveniently. In order to this monitoring become a routine among the producers of potted flowers, a standardization of non-destructive methods and easy application are required. This study was conducted in order to adapt of the “PourThru” methodology for substrate evaluation with different particle sizes. It was conducted on substrates with different particle sizes. Two tests were performed to define the amount of water to be applied, the time between irrigation and the collect of the leachate. Both tests were done using substrates with grain size 4-2 mm, 2-1 mm <4 mm <2 mm <1 mm and four repetitions. For the test I, we used the factorial 5 x 4 (5 particle sizes and 4 volumes of water), with volumes of 50, 75, 100 and 125 mL. For test II, we used the 5 x 5 factorial (5 granulometry balance and 5 times), with times of 30, 60, 90, 120 and 150 minutes. The leach solution was evaluated for electrical conductivity and pH. The methodology presented showed constraints when the substrates had particle sizes between 4 and 2 mm, and less than 1 mm. The larger the particle sizes is, the greater is the formation of preferential channels that leads to the possibility of mixing the water used as carrier and the solution to be leached is. The smaller the particle size is, the greater is the tendency of adsorption of the nutrients by the particles. For the pine bark substrate and vase with 1.3 L, it is suggested 60 minutes as settling time and the application of 75 mL of water for leaching the displacement.


2006 ◽  
Vol 24 (3) ◽  
pp. 165-168
Author(s):  
Stanislav V. Magnitskiy ◽  
Claudio C. Pasian ◽  
Mark A. Bennett ◽  
James D. Metzger

Abstract Soaking French marigold seeds in growth regulator solutions produced larger reductions in seedling height than foliar sprays. Seeds soaked in 1 to 5 ppm uniconazole solutions for 0.15, 5, or 45 min resulted in plants that were up to 23% shorter than controls at 30 DAS, whereas foliar applications of 10 to 20 ppm uniconazole solutions resulted in plants 18% shorter than controls at 14 DAS. French marigold seedlings from seeds soaked in 60 pm ancymidol for 5 or 45 min were 5 or 6%, respectively, shorter than controls. Foliar spray applications of 25 or 100 ppm ancymidol to French marigold seedlings resulted in plants 8% shorter than controls. Chlormequat solutions applied either as a seed soak (1000–5000 ppm) or foliar spray (500–3000 ppm) did not reduce French marigold seedling height. Emergence of French marigold seedlings from seeds soaked in uniconazole, ancymidol, or chlormequat solutions was not different from that of control seeds. No effect on seedling height or emergence was found when soaking celosia seeds in uniconazole, ancymidol, or chlormequat solutions. Spraying celosia seedlings with uniconazole, ancymidol, or chlormequat solutions did not reduce seedling height.


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