scholarly journals THE EFFECTS OF GROWTH REGULATORS ON FLOWERING, BRANCHING PATTERNS AND GROWTH OF NEW GUINEA IMPATIENS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1099c-1099
Author(s):  
J. Phillip McKnight ◽  
G. L. Klingaman

Eighteen New Guinea impatiens cultivars were evaluated for performance as bedding plants and for suitability as hanging basket plants. The cultivars were treated with three growth retarding chemicals (B-9, Sumagic and Cutless) to determine their effect on plant growth, branching and overall flower development. Two applications of 2500 ppm B-9 produced the most commercially acceptable plants. Height and spread were reduced by approximately 30 percent with no reduction in the number of flowers produced or the number of days to bloom. Cutless and Sumagic applications reduced growth approximately 50 percent and delayed blooming as much as 2 weeks when compared to the untreated control. Growth regulator treatment had no effect on the number of branches produced except with Sumagic which resulted in an overall reduction in branching.

HortScience ◽  
2017 ◽  
Vol 52 (10) ◽  
pp. 1362-1367 ◽  
Author(s):  
Josh B. Henry ◽  
Ingram McCall ◽  
Brian Jackson ◽  
Brian E. Whipker

A series of experiments investigated the effects of increasing phosphate–phosphorus (P) concentrations on the growth and development of four horticultural species. In experiment 1, petunia [Petunia atkinsiana (Sweet) D. Don ex W.H. Baxter] plants were grown using eight P concentrations, and we found that the upper bound for plant growth was at 8.72–9.08 mg·L−1 P, whereas concentrations ≤2.5 mg·L−1 P caused P deficiency symptoms. Experiment 2 investigated P growth response in two cultivars each of New Guinea impatiens (Impatiens hawkeri W. Bull) and vinca [Catharanthus roseus (L.) G. Don]. Growth for these plants was maximized with 6.43–12.42 mg·L−1 P. In experiment 3, ornamental peppers (Capsicum annuum L. ‘Tango Red’) were given an initial concentration of P for 6 weeks and then switched to 0 mg·L−1 P to observe whether plants could be supplied with sufficient levels of P, and finished without P to keep them compact. Plants switched to restricted P began developing P deficiency symptoms within 3 weeks; however, restricting P successfully limited plant growth. These experiments indicated that current P fertilization regimens exceed the P requirements of these bedding plants, and depending on species, concentrations of 5–15 mg·L−1 P maximize growth.


2015 ◽  
Vol 25 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Youping Sun ◽  
Genhua Niu ◽  
Andrew K. Koeser ◽  
Guihong Bi ◽  
Victoria Anderson ◽  
...  

As the green industry is moving toward sustainability to meet the demands of society, the use of biocontainers as alternatives to petroleum-based plastic containers has drawn significant attention. Field trials of seven plantable biocontainers (coir, manure, peat, rice hull, soil wrap, straw, and wood fiber) were conducted in 2011 and 2012 at five locations in the United States to assess the influence of direct-plant biocontainers on plant growth and establishment and the rate of container decomposition in landscape. In 2011, container type did not affect the growth of any of the three species used in this study with an exception in one location. The three species were ‘Sunpatiens Compact Magenta’ new guinea impatiens (Impatiens ×hybrida), ‘Luscious Citrus’ lantana (Lantana camara), and ‘Senorita Rosalita’ cleome (Cleome ×hybrida). In 2012, the effect of container type on plant growth varied with location and species. Cleome, new guinea impatiens, and lantana plants grown in coir and straw containers were in general smaller than those in peat, plastic, rice hull, and wood fiber containers. After 3 to 4 months in the field, manure containers had on average the highest rate of decomposition at 88% for all five locations and two growing seasons. The levels of decomposition of other containers, straw, wood fiber, soil wrap, peat, coir, and rice hull were 47%, 46%, 42%, 38%, 25%, and 18%, respectively, in descending order. Plantable containers did not hinder plant establishment and posttransplant plant growth. The impact of container type on plant growth was smaller compared with that of location (climate). Similarly, the impact of plant species on pot decomposition was smaller compared with that of pot material.


1998 ◽  
Vol 16 (3) ◽  
pp. 138-142
Author(s):  
Joyce G. Latimer ◽  
Ronald D. Oetting

Abstract Conditioning treatments were evaluated for effects on growth of bedding plants during greenhouse production and carryover effects on plant performance in the landscape. Treatments included two fertilization regimes using a complete water soluble fertilizer applied three times/week at 500 ppm N, designated ‘high N’, or at 50 ppm N, designated the ‘low N’ treatment. Other treatments included: ebb and flow irrigation, drought stress for up to 2 h wilt/day, 5000 ppm B-Nine (daminozide), 45 ppm Bonzi (paclobutrazol; 180 ppm on columbine), and brushing (40 strokes twice daily). Unless otherwise noted all plants, including controls, were maintained well-irrigated and fertilized with 250 ppm N three times/week. Marigolds and New Guinea impatiens grown under low N during greenhouse production exhibited reduced plant height and width relative to control plants at 4 weeks after planting (WAP) in the landscape. Plant quality ratings of all species conditioned with low N were lower than those of controls 2 and 4 WAP. Plant height of New Guinea impatiens conditioned with high N was greater than that of controls 4 WAP in the landscape. Marigolds subjected to drought in the greenhouse were still shorter than controls 2 and 4 WAP. Persistent height reductions in the landscape in response to B-Nine were observed in ageratum 2 and 4 WAP and to Bonzi in New Guinea impatiens through 8 WAP. Brushing reduced the height of all species except ageratum in the greenhouse, but had no carryover effect on plant growth in the landscape. At 4 weeks after treatment, plant height of columbine treated with low or high N, drought, brushing, or B-Nine was reduced relative to controls, but all plants were similar in size in the landscape.


2013 ◽  
Vol 31 (1) ◽  
pp. 27-29
Author(s):  
K.A. Hester ◽  
G. Bi ◽  
M.A. Czarnota ◽  
A. Fulcher ◽  
G.J. Keever ◽  
...  

Hydrangeas are an increasingly popular group of shrubs which are prized for their showy inflorescence. Nursery crop producers grow numerous hydrangea varieties for the landscape and florist markets. Hydrangeas are typically hand-pruned during propagation and production to promote compaction and to increase the number of branches which has potential for increasing blooms and marketability. Identifying a plant growth regulator (PGR) treatment that effectively improves the architecture of hydrangeas became an IR-4 Project research priority for 2011. Research evaluating Augeo (dikegulac sodium), Configure (benzyladenine) and Florel (ethephon) shows worthwhile results. Augeo (800 and 1600 ppm) significantly increased branching compared to untreated pots of florist varieties Hydrangea macrophylla ‘Merritt's Supreme’ and landscape varieties H. macrophylla ‘Nikko Blue’ and H. paniculata ‘Limelight’. Configure (300 ppm and 600 ppm) and Florel (500 and 1000 ppm) did not significantly improve branching in five of six trials compared to the control. Significant chlorosis on Augeo treated plants was observed initially but this diminished by 6 weeks after treatment (WAT) for four out of six trials. Little to no crop injury was observed with Configure or Florel treatments to hydrangea liners. This research shows promise for identifying a plant growth regulator treatment to meet the demand for improved branching on hydrangea.


2018 ◽  
Vol 19 (4) ◽  
pp. 324-328
Author(s):  
W. Garrett Owen ◽  
Brian E. Whipker ◽  
Josh B. Henry ◽  
Paul Cockson ◽  
Hunter Landis

New Guinea impatiens (Impatiens hawkeri) are popular bedding plants, but the knowledge of diagnosing abiotic disorders during greenhouse production is evolving. Symptomology of nutrient deficiencies and excessive fertilization have been extensively documented. Exact symptomology of low substrate pH (<5.5) and toxic iron (Fe) and/or manganese (Mn) leaf tissue levels are not defined or photographed, thereby aiding in diagnosis. Therefore, the objective of the diagnostic guide was to photograph symptomology and document the tissue levels in New Guinea impatiens to provide a definitive guide of low substrate pH–induced Fe and/or Mn toxicity.


2018 ◽  
Vol 28 (2) ◽  
pp. 136-142
Author(s):  
Josh B. Henry ◽  
Ingram McCall ◽  
Brian E. Whipker

Chemical plant growth retardants (PGRs) are commonly used to produce compact bedding plants. Few PGRs are labeled for sensitive species because of the concern of excessive restriction of stem elongation or phytotoxicity. Growers are therefore presented with a dilemma: produce untreated plants that may be too tall or risk applying a PGR that can potentially lead to irreversible aesthetic damage to the plant. Nutrient restriction, specifically of phosphorus (P), may be used to control plant height. This study was conducted to determine if restricting P fertilization yielded comparable growth control to plants produced with PGRs. Two cultivars each of new guinea impatiens (Impatiens hawkeri) and angelonia (Angelonia angustifolia) were grown using five fertilizers that varied by P concentration (0, 2.5, 5, 10, and 20 ppm). Half of the plants from each P fertilizer concentration were treated with paclobutrazol at 4 and 5 weeks after transplant for angelonia and new guinea impatiens, respectively. On termination of the experiment, data were collected for height, diameter, and dry weight, which were used to determine a growth index (GI). Angelonia GI values were maximized with 7–9 ppm P, whereas new guinea impatiens GI was maximized with 8–11 ppm P. Concentrations of 3–5 ppm P provided similar height control to plants grown with nonlimiting P and a paclobutrazol application. Concentrations of ≤2.5 ppm P resulted in low-quality plants with visual symptoms of P deficiency. These results indicate that a narrow range of P concentrations may be used to control stem elongation and keep plants compact.


2007 ◽  
Vol 132 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Dharmalingam S. Pitchay ◽  
Jonathan M. Frantz ◽  
James C. Locke ◽  
Charles R. Krause ◽  
George C. J. Fernandez

Plant performance and appearance in deficient and toxic levels of nutrients are well characterized. However, less is known about the potential subtleties of plant growth, form, development, nutrient uptake, and biotic stress tolerance in the broad tolerable range. Begonia [Beg (Begonia × tuberhybrida Voss)] and new guinea impatiens [NGI (Impatiens hawkeri Bull.)] were grown over a wide range of N (from 1.78 to 57.1 mm NH4:NO3 ratio at a 1:1 ratio supplied as nutrient solution) in a peat:perlite soilless substrate in greenhouse conditions. Plant growth, development, chlorophyll content, leaf angle, nutrient uptake, tissue caloric value, and susceptibility to Botrytis cinerea Pers.:Fr. disease were evaluated in two experiments. Elevated N supply resulted in decreased plant height (16% in Beg and 7% to 16% in NGI), flower count (3% to 48% in Beg and 7% to 49% in NGI), bud numbers (23% to 80% in Beg), canopy area (11% to 33% in NGI), and mass (21% to 33% in Beg and 18% to 58% in NGI). Chlorophyll content saturated at an N supply of 28.6 mm. N uptake efficiency, shoot N use efficiency, and shoot N utilization efficiency decreased with increasing N supply. Elevated levels of N supply from 7.15 to 57.1 mm also increased the susceptibility of Beg to B. cinerea disease by 10% to 80% in stems and 3% to 14% in leaves. The increase in susceptibility also corresponded with increased tissue energy content (kJ·g−1) and altered leaf orientation. This study indicates many plant changes occur between nutrient extremes that can have a significant impact on growth, development, and the ability to withstand disease.


Plant Disease ◽  
2020 ◽  
Author(s):  
Yingyu Liu ◽  
Tyler Helmann ◽  
Paul Stodghill ◽  
Melanie Filiatrault

New Guinea Impatiens (NGI, Impatiens hawkeri) are popular bedding plants that can be affected by a number of pathogens. Using 16S rDNA sequencing and genus-specific PCR, we identified the first Dickeya dianthicola strain isolated from NGI presented with blackleg symptoms, herein designated as D. dianthicola 67-19. Here, we report a high-quality complete and annotated genome sequence of D. dianthicola 67-19. The 4,851,809 bp genome was assembled with Nanopore reads and polished with Illumina reads, yielding 422× and 105× coverage, respectively. This closed genome provides a resource for future research on comparative genomics and biology of D. dianthicola, which could translate to improved detection and disease management.


HortScience ◽  
1991 ◽  
Vol 26 (1) ◽  
pp. 47-49 ◽  
Author(s):  
Diana L. Dostal ◽  
Nancy Howard Agnew ◽  
Richard J. Gladon ◽  
Jack L. Weigle

Exposure to exogenous ethylene (C2H4) caused corolla abscission of New Guinea impatiens (Impatiens × hawkeri `Sunfire'). Abscission varied with time of exposure and C2H4 concentration. Ethylene at ≥ 1 μl·liter-1 and exposure times of 4 or more hours caused 80% to 100% corolla abscission. Simulated shipping of untreated control plants caused ≈ 65% corolla abscission. Plants pretreated with silver thiosulfate (STS) and (aminooxy)acetic acid (AOA) and subsequently exposed to simulated shipping were not different from one another, and both treatments reduced corolla abscission to ≈ 20% when applied at 1.0 mm. Plants pretreated with STS and exposed to `exogenous C2H4 showed 0% abscission, whereas plants pretreated with AOA showed no reduction in abscission when compared with control plants.


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