scholarly journals 154 Suppressing Purple Passion (Gynura aurantiaca) Flowering Using Selected Plant Growth Regulators

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 416C-416
Author(s):  
Jianjun Chen ◽  
Russell D. Caldwell ◽  
Cynthia A. Robinson

Gynura aurantiaca is a colorful foliage plant with creeping stems and velvety purple hairs that cover the green leaves. It grows rapidly, but is cultivated primarily for those attractive purple leaves. Annually during the spring, this plant produces prominent flowers both in appearance and smell, gaudy and malodorous. Flowering coupled with acquiring an over-grown leggy appearance have been key limitations in its production and use in interiorscaping. This study was undertaken to determine if an available commercial plant growth regulator could inhibit flowering. A-Rest (ancymidol), B-Nine (daminozide), Bonzi (paclobutrazol), cycocel (chlormequat chloride) and florel (ethephon) each diluted to three different concentrations were sprayed in two applications in early spring at 2-week intervals. Flowering and bud numbers and plant growth (number of lateral shoots, vine lengths and internode lengths) were recorded. Results indicated that applications of A-Rest, B-Nine, Bonzi and Cycocel, regardless of treatment concentrations, were ineffective in suppressing the flowering of this plant; whereas, florel completely suppressed flowering at the three concentrations used. The florel-treated plants also grew more lateral shoots, which produced a compact and dense bush-look, indicating that appropriate concentrations of florel application not only will stop flowering of purple passion but can also improve and prolong its aesthetic value as a potted or hanging-basket interior plant.

2002 ◽  
Vol 20 (4) ◽  
pp. 228-231
Author(s):  
Jianjun Chen ◽  
Richard J. Henny ◽  
Russell D. Caldwell

Abstract Gynura aurantiaca is a colorful foliage plant with velvety purple hairs that cover the green leaves and stems. However, its malodorous flowers and tendency towards a leggy appearance have been key limitations to its production and use for interiorscaping. This study was undertaken to determine if plant growth regulators could suppress its flowering and excessive growth, while improving its overall quality. A-Rest (ancymidol), B-Nine (daminozide), Bonzi (paclobutrazol), Cycocel (chlormequat chloride), and Florel (ethephon) were applied as foliar sprays in two applications in March at a two-week interval. Florel completely inhibited flowering but A-Rest, B-Nine, Bonzi, and Cycocel were ineffective in suppressing flowering. Florel-treated plants also produced more lateral shoots resulting in a compact and dense bush-like appearance, which improved and prolonged the aesthetic value of Gynura as a container-grown or hanging-basket interior plant. Whereas, plants treated by A-Rest, B-Nine, Bonzi, or Cycocel exhibited little improvement in their appearance compared to the control; some treatments were even detrimental. Regardless of application concentrations, subsequent growth of plants after pruning or rooting of cuttings was not affected by previous treatments of growth regulators.


2012 ◽  
Vol 42 (12) ◽  
pp. 2138-2144 ◽  
Author(s):  
Fábio Rafael Echer ◽  
Ciro Antonio Rosolem

Most of Brazilian cotton is produced in regions where annual rainfall exceeds 1,500mm, hence plant growth regulators (PGR) may be washed from the leaves before being absorbed. The objective of this research was to evaluate mepiquat chloride and chlormequat chloride washing from cotton leaves by rains occurring at different moments post spraying. The experiment was conducted in a greenhouse. Both PGR were sprayed to cotton at pin-head square at 15g ha-1 a.i. with and without a silicon-based adjuvant, and simulated rains were applied at 0, 0.75, 1.5, 3.0, 6.0, 12.0 and 24 hours after spraying, plus a control without rainfall. Addition of silicon adjuvant increased PGR uptake. Rainfall occurring up to 24 hours after spraying resulted in some PGR loss from cotton leaves, mainly in the absence of the adjuvant. The decreased uptake implies that in order to achieve the desired level of growth reduction, at least a fraction of the original PGR rate should be reapplied.


2004 ◽  
Vol 31 (2) ◽  
pp. 70-73 ◽  
Author(s):  
J. P. Beasley ◽  
W. J. Grichar ◽  
D. L. Jordan ◽  
R. G. Lemon ◽  
B. A. Besler ◽  
...  

Abstract Experiments were conducted from 1996 through 2001 in Georgia, North Carolina, and Texas to determine peanut response to the commercial plant growth regulator Early Harvest® (a commercial mixture of cytokinin, gibberellic acid, and indole butyric acid). Early Harvest (applied in the seed furrow) or Early Harvest TST (applied as a dry seed treatment) followed by four foliar applications (four-leaf peanut, initial pegging, 14 d after initial pegging, and pod fill), was compared to non-treated peanut in five, 13, and three experiments in these respective states. Early Harvest did not affect pod yield or gross economic value of peanut regardless of location, cultivar, or edaphic and environmental conditions. These data suggest that a spray program consisting of Early Harvest most likely will not improve pod yield or gross economic value of peanut.


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


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).


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 484A-484 ◽  
Author(s):  
Jeff S. Kuehny ◽  
Patricia Branch

Lateral branches of poinsettia tend to break from the main stem as plants reach maturity. The cause of poor stem strength is not known; however, suggested factors implicated in poor stem strength are: rate of nitrogen fertilizer used, type of plant growth regulator used, crowding of plants, or stem diameter of the cutting. Four different experiments were conducted to determine if these factors affected stem strength of poinsettia. Experiment 1: `Freedom Red', `Success', `V-17 Angelika Red', `Red Sails', `Nutcracker Red', `Cortez', `Maren', and `Red Splendor' poinsettia were fertilized with 20N–1P0–20K at 75, 75/125, 125/200, or 200 ppm N drip fertigation with zero leachate. Experiment 2: Three plant growth regulators were applied to `Pearl' and `Jolly Red' poinsettias. Experiment 3: `Freedom Red' plants were grown in a 625, 900, 1225, or 1600 cm2 area. Experiment 4: Rooted `Freedom Red' cuttings with stem diameters of 4.5, 5.5, 6.5, or 7.5 mm were used. A force meter was used to determine the strength of each lateral on the main stem of the six replications in each experiment. The lower laterals had the least stem strength and the top lateral had the highest stem strength for all treatments in all experiments. The stem strengths of some cultivars in experiment 1 were stronger at the lower fertilizer rates. Type of plant growth regulator had no significant affect on most poinsettia cultivars. The stem strengths of poinsettias in experiments 3 and 4 varied according to which lateral was measured.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1124e-1124
Author(s):  
Guochen Yang ◽  
P. E. Read

Vanhoutte's spiraea has been propagated in vitro using explants from softwood growth of dormant stems forced in a solution containing 200 mg/l 8-hydroxyquinoline citrate (8-HQC) and 2% sucrose (Yang and Read, 1989). Objectives to further utilize this system were to determine the feasibility of applying plant growth regulators (PGR) via the forcing solution to softwood growth from forced dormant stems and to study the resulting influence on in vitro culture. BA and GA3 were placed in the forcing solution at various concentrations, including a zero PGR control. Explants were cultured on Linsmaier and Skoog (LS) medium containing zero PGR or different amounts of BA or thidiazuron (TDZ) or combinations of BA and IAA. Control explants placed on LS medium supplemented with 5uM BA with or without 1 or 5uM IAA, or with 0.5 or 0.75 uM TDZ alone produced the best shoot proliferation. BA in the forcing solution stimulated micropropagation, while GA3 caused less proliferation than explants from control solutions. Forcing solutions containing PGR are useful for manipulating responses of plant tissues cultured in vitro and for studying PGR influence on woody plant physiology.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 886d-886
Author(s):  
Todd J. Cavins

Anti-gibberellin plant growth regulators (PGRs) not only affect cell elongation, but other biochemical processes. The experimental PGR A-1699 DF was evaluated for efficacy of height and width control as well as effect on flower petal pigmentation. While the active ingredient in A-1699 DF has proven effective for height control on several crops, that was not observed on Impatiens `Accent Cranberry' in this study. However, A-1699 DF did affect flower petal pigmentation. A-1699 DF likely inhibited anthocyanin production that resulted in light pink versus cranberry flower petals observed on the control, Paczol, and B-Nine/Cycocel PGR applications.


2014 ◽  
Vol 24 (3) ◽  
pp. 313-317
Author(s):  
Rachael E. Pepin ◽  
Janet C. Cole

Summer and fall studies investigated the control of growth of bee balm (Monarda didyma ‘Marshall’s Delight’) by paclobutrazol, uniconazole, or flurprimidol applied to the substrate as a surface drench or through subirrigation. Flurprimidol and uniconazole were applied at 0, 0.5, 1.0, 1.5, or 2.0 ppm (0, 0.09, 0.18, 0.27, or 2.0 mg/pot), while paclobutrazol was applied at 0, 2, 4, 6, or 8 ppm (0, 0.6, 1.2, 1.8, or 2.4 mg/pot). Substrate drench applications were more effective than applications through subirrigation at reducing plant growth. Few trends in application concentrations within plant growth regulator occurred for the plant parameters measured. Based on inconsistent plant responses between the two studies and few differences among application concentrations, we do not recommend any of these plant growth regulators for controlling plant size of bee balm during production without further testing in production environments specific to bee balm.


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