scholarly journals 018 EFFECTS OF ANCYMIDOL, PACLOBUTRAZOL, AND UNICONAZOLE ON GROWTH AND FLOWERING OF ACHIMENES cv HILDA UNDER TWO LIGHT LEVELS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 430b-430
Author(s):  
J. C. Vlahos
Keyword(s):  
Plant Height ◽  
Light Level ◽  
The Other ◽  
Growth Retardants ◽  
Axillary Shoots ◽  
Full Sunlight ◽  
Foliar Sprays ◽  
Light Levels ◽  
Mode Of Application ◽  
Reduced Light

Plants of Achimenes cv Hilda were treated with foliar sprays of Ancymidol, Paclobutrazol and Uniconazole at 3 different concentrations each, and were placed in a greenhouse at 21°C under 2 light levels (0 and 40% light exclusion) for 12 weeks. Reduced light level decreased plant height, number of axillary shoots and flowers. The three growth retardants in any concentration, supressed development of axillary shoots and flowers. Ancymidol at 25 and 50 mg.1-1, Uniconazole at 5 mg.1-1 and Paclobutrazol at 25, 50 or 100 mg.1-1 decreased plant height and number of leaf whorls. Number of rhizomes was reduced by the 3 chemicals at the highest concentration only. Paclobutrazol was most effective than the other 2 growth retardants. Effects of treatments were more pronounced under shade rather than in full sunlight. Days to anthesis was not affected by any of the treatments except by Paclobutrazol at 100 mg.1-1. The use of these growth retardants in concentration and mode of application similar to those used in this study is not recommended for “Hilda” as height retardation significantly reduces number of flowers

scholarly journals HOREHOUND (Marrubium vulgaris L.) PRODUCTION IN NORTHERN AMERICA: RESPONSES TO MULCH, SHADING, AND NITROGEN TREATMENT

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1162b-1162
Author(s):  
Z.Y. Mao ◽  
Lyle E. Craker
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Size ◽  
Light Level ◽  
High Nitrogen ◽  
Light Levels ◽  
Leaf Chlorophyll ◽  
Nitrogen Treatment ◽  
Reduced Light ◽  
Field Production ◽  
Number Of Branches

Mulch, light level, and nitrogen fertilization were tested for their effects on productivity of horehound (Marrubium vulgaris L.). Yield of this plant increased under mulched conditions and with the addition of nitrogen fertilizer. Yield decreased with reduced light levels. Productivity of individual plants correlated with the number of branches per plant, leaf size, and leaf chlorophyll content. The number of branches per plant decreased with increased shading, but increased with increased nitrogen fertilization. The influence of mulch and shading on productivity could be due to the changes in soil temperature and in soil water potentials. Full-sun, high nitrogen, and mulch are suggested for optimum field production of horehound.

scholarly journals Micropropagation of Rhododendron chapmanii

1986 ◽  
Vol 4 (1) ◽  
pp. 26-29
Author(s):  
Frank A. Blazich ◽  
Cheryl G. Giles ◽  
Carole M. Haemmerle
Keyword(s):  
Shoot Multiplication ◽  
Shoot Elongation ◽  
Shoot Formation ◽  
Multiple Shoot ◽  
Axillary Shoot ◽  
Axillary Shoots ◽  
Light Levels ◽  
Axillary Shoot Multiplication ◽  
Reduced Light

Shoot tips excised from Chapman's rhododendron (Rhododendron chapmanii A. Gray) were surface sterilized, the terminal portions were removed (decapitated) and the shoots placed in liquid Woody Plant Medium (WPM) supplemented with 8 μM (1.6 ppm) 6(γ, γ-dimethylallylamino)-purine (2iP). Within 2 to 3 months axillary shoots excised, decapitated and cultured on agarsolidified WPM supplemented with 49 μM (10 ppm) 2iP. Multiple shoot formation consisting of adventitious and axillary shoots was observed within 4 to 6 months. These shoots were transferred to WPM supplemented With 8 μM (1.6 ppm) 2iP and cultured under reduced light levels to stimulate shoot elongation. Shoots ≥ 10 mm (0.4 in.) were harvested (microcuttings) and rooted using non-in vitro procedures. Enhancement of axillary shoot multiplication was achieved by culturing decapitated axillary shoots under reduced light levels in a horizontal position on WPM supplemented WIth 8 μM (1.6 ppm) 2iP.

The Effect of Reduced Light Intensity on Grass Weeds

Weed Science ◽  
2017 ◽  
Vol 65 (5) ◽  
pp. 603-613 ◽  
Author(s):  
Muhammad Yasin ◽  
Eva Rosenqvist ◽  
Christian Andreasen
Keyword(s):  
Light Intensity ◽  
Plant Height ◽  
Dry Matter ◽  
Photochemical Efficiency ◽  
Grass Species ◽  
Weed Species ◽  
Annual Bluegrass ◽  
Light Levels ◽  
Number Of Leaves ◽  
Reduced Light

The effect of reduced light intensity on the growth and development of three common grass weeds, blackgrass, silky windgrass, and annual bluegrass, was studied. Two identical greenhouse experiments displaced in time were performed with six light levels aiming at 0%, 20%, 50%, 80%, 90%, and 95% shade corresponding to a mean daily light integral (DLI) of 12.4, 9.63, 7.13, 2.74, 0.95, and 0.69 mol m−2d−1in experiment 1 and 21.2, 18.0, 10.7, 3.71, 1.64, 1.20 mol m−2d−1in experiment 2. Climate screens of acrylic fabric were used to create the light levels. A DLI of 0.69 to 3.71 mol m−2d−1substantially reduced the plant height, the number of leaves, leaf chlorophyll content index, stomatal conductance, maximum photochemical efficiency of photosystem II, and dry matter of blackgrass. It also reduced plant height, the number of leaves, and dry matter and delayed flowering of windgrass and annual bluegrass. Annual bluegrass reacted most rapidly when light levels increased from the lowest levels by producing more leaves. DLI thresholds for blooming were estimated to be about 7.13 mol m−2d−1for windgrass and 1.64 mol m−2d−1for annual bluegrass. Annual bluegrass was able to bloom and sustain biomass even at a DLI of 1.64 mol m−2d−1. This ability may contribute to an explanation of why annual bluegrass is among the most common weed species in highly competitive and well-fertilized crops even though it is much smaller than the two other grass species.

scholarly journals (50) Evaluating Low Light Level Effects on Chlorophyll Content and Commercial Quality in Several Species of Bambuseae

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1037B-1037
Author(s):  
Harry G. Simmons ◽  
Alisara Menakanit ◽  
Surawit Wannakrairoj ◽  
Poonpipope Kasemsap
Keyword(s):  
Chlorophyll Content ◽  
Extreme Temperature ◽  
Light Level ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Levels ◽  
Foliage Plant ◽  
Reduced Light

Bamboo has increasingly become a popular exterior ornamental plant because of its durability, versatility, and evergreen qualities in conditions of extreme temperature and moisture variations. Use as an interior foliage plant has been limited due to the difficulty of finding species adaptable to lower light levels. Nineteen species from seven genera (Bambusa, Cephalostachyum, Dendrocalamus, Gigantochloa, Schizostachyum, Thyrsostachys, and Vietnamosasa) were evaluated. Fifteen plants from each species were potted in like conditions (50% leaf mold; 50% topsoil; 5 g of 14–14–14 controlled-release fertilizer) and grown under a maximum daily photosynthetic photon flux density (PPFD) range between 1200 to 2000 μmol·m-2·s-1 for 6 weeks. Chlorophyll content of leaves was measured. The commercial quality of leaves, culms, and general appearance was also recorded. Light was then limited to a maximum PPFD of 150 to 300 μmol m-2s-1 for 6 weeks and all measurements were again recorded. Five species had significant increases in chlorophyll content after the 6-week period of reduced light levels. Species with a larger maturity size had a greater mortality percentage as well as lower quality leaf and overall appearance when grown under reduced light levels. Culm quality remained constant in 18 of the 19 species after the 6-week period. Vietnamosasa ciliata showed the greatest increase in chlorophyll levels as well as highest commercial quality of leaf and overall appearance.

scholarly journals Are plant growth retardants a strategy to decrease lodging and increase yield of sunflower?

2016 ◽  
Vol 7 (1) ◽  
pp. 154 ◽  
Author(s):  
Marcia Eugenia Amaral Carvalho ◽  
Paulo Roberto de Camargo e Castro ◽  
Marcos Vinicius de Castro Ferraz Junior ◽  
Ana Carolina Cabrera Machado Mendes
Keyword(s):  
Plant Growth ◽  
Gibberellic Acid ◽  
Plant Height ◽  
Dry Mass ◽  
The Other ◽  
Alternative Strategy ◽  
Growth Retardants ◽  
Other Hand ◽  
Plant Growth Retardants ◽  
Potential Strategy

One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied.

scholarly journals Florida Red Ruffles and Florida Irish Lace: Two New Lance-leaf Caladium Cultivars

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 564
Author(s):  
Gary J. Wilfret
Keyword(s):  
Plant Height ◽  
Breeding Program ◽  
The Other ◽  
University Of Florida ◽  
Green Leaves ◽  
Cold Tolerant ◽  
Production Indices ◽  
Dark Green ◽  
The University ◽  
Reduced Light

Two lance-leaf caladium cultivars are to be released from the ornamental breeding program at the University of Florida. `Red Ruffles', whose pedigree is Red Frill × (`Red Frill' × `Candidum Jr.'), has elongated medium red leaves with ruffled green margins. Plants are upright with strong petioles, have leaf blades 25 cm long and 14 cm wide, and attain a height of 61 cm when grown in full sun in the field. Plants have more leaves and are more cold tolerant than `Red Frill', the major red lance-leaf cultivar of commerce. Tuber yields of `Red Ruffles' are similar to `Red Frill' but less than `Rosalie', with production indices of 95.0, 97.8, and 121.0, respectively. Foliage of `Red Ruffles' is more upright and less likely to elongate under reduced light than the other cultivars. `Irish Lace', an F2 selection from a cross of “Candidum Jr.' × “Red Frill', has elongated dark green leaves with heavily ruffled margins, which are etched with a thin red border. Leaf blades are 26 cm long and 8 cm wide and have heavy substance. Plant height is 65 cm in the field. Tuber yields of `Irish Lace' are greater than `White Wing', a major green/white cultivar. Use of a green caladium would be as a border or a mixture with red or white lance-leaf cultivars.

scholarly journals Influence of Benzyladenine, Trinexapac-ethyl, or Uniconazole Applications on Height and Tillering of Six Ornamental Grasses

2009 ◽  
Vol 19 (4) ◽  
pp. 737-742 ◽  
Author(s):  
Sonali R. Padhye ◽  
Judith K. Groninger
Keyword(s):  
Plant Height ◽  
Initial Treatment ◽  
Tiller Number ◽  
The Other ◽  
Miscanthus Sinensis ◽  
Foliar Sprays ◽  
Ornamental Grasses ◽  
Cortaderia Selloana ◽  
Spray Applications

Three ornamental grasses, each within the families Cyperaceae [leatherleaf sedge (Carex buchananii), ‘Frosted Curls’ sedge (Carex comans), and ‘Toffee Twist’ sedge (Carex flagellifera)] and Poaceae [‘Rosea’ pampas grass (Cortaderia selloana), ‘Gracillimus’ miscanthus (Miscanthus sinensis), and muhly grass (Muhlenbergia capillaris)], received two foliar sprays 2 weeks apart of benzyladenine (BA) at 500 or 1000 mg·L−1, trinexapac-ethyl (TE) at 220 mg·L−1, or uniconazole at 20 or 40 mg·L−1. The influence of these spray applications on plant height and tiller number was assessed 0, 2, 4, and 8 weeks after the initial treatment (WAIT). Benzyladenine applications did not suppress the height of leatherleaf sedge or ‘Gracillimus’ miscanthus, yet did suppress the height of the other ornamental grasses by <15% compared to the controls, depending on the concentration used and the time. Applications of BA increased tiller production only in ‘Toffee Twist’ sedge at 2 and 4 WAIT compared to the controls; however, at 8 WAIT, this increase was diminished. Depending on the species, uniconazole suppressed the height of the Cyperaceae grasses by 11% to 22% compared to the controls at 8 WAIT. In Poaceae species, uniconazole suppressed the height of only ‘Rosea’ pampas grass by up to 32% compared to the controls. Uniconazole applications did not increase the tillering of any ornamental grasses tested, except ‘Toffee Twist’ sedge at 8 WAIT. Within Cyperaceae, TE suppressed the height of only ‘Toffee Twist’ sedge compared to the controls, while TE effectively controlled the height of all Poaceae grasses. Based on the species and time, TE application elicited up to 37% height suppression compared to the controls of Poaceae grasses, while it did not influence the tiller number of any ornamental grasses in this study.

Change of color appearance due to extremely high light level: corresponding colors under 100 and 3000 cd/m2

2019 ◽  
Vol 2019 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Wenyu Bao ◽  
Minchen Wei
Keyword(s):  
Light Level ◽  
Limited Range ◽  
High Light ◽  
Color Preference ◽  
Color Appearance ◽  
Appearance Model ◽  
Color Matching ◽  
Light Levels ◽  
Appearance Models ◽  
Psychophysical Study

Great efforts have been made to develop color appearance models to predict color appearance of stimuli under various viewing conditions. CIECAM02, the most widely used color appearance model, and many other color appearance models were all developed based on corresponding color datasets, including LUTCHI data. Though the effect of adapting light level on color appearance, which is known as "Hunt Effect", is well known, most of the corresponding color datasets were collected within a limited range of light levels (i.e., below 700 cd/m2), which was much lower than that under daylight. A recent study investigating color preference of an artwork under various light levels from 20 to 15000 lx suggested that the existing color appearance models may not accurately characterize the color appearance of stimuli under extremely high light levels, based on the assumption that the same preference judgements were due to the same color appearance. This article reports a psychophysical study, which was designed to directly collect corresponding colors under two light levels— 100 and 3000 cd/m2 (i.e., ≈ 314 and 9420 lx). Human observers completed haploscopic color matching for four color stimuli (i.e., red, green, blue, and yellow) under the two light levels at 2700 or 6500 K. Though the Hunt Effect was supported by the results, CIECAM02 was found to have large errors under the extremely high light levels, especially when the CCT was low.

Effect of Irradiance Level and Paclobutrazol on Reducation of Leaf Damage in Begonia × cheimantha

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446d-446
Author(s):  
Beyounghan Yoon ◽  
Harvey J. Lang
Keyword(s):  
Day Treatment ◽  
Leaf Damage ◽  
Growth Retardants ◽  
Damage Development ◽  
Long Day ◽  
Leaf Chlorosis ◽  
Shade Cloth ◽  
Growing Conditions ◽  
Reduced Light ◽  
Shade Plants

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.

Influence of Light on Fruit Set of French Hybrid Grapes

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 510f-511 ◽  
Author(s):  
D.C. Ferree ◽  
S.J. McArtney ◽  
D.M. Scurlock
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Fruit Set ◽  
Light Level ◽  
Fruit Color ◽  
Soluble Solids ◽  
Hue Angle ◽  
Reduced Light ◽  
Negative Linear Relationship ◽  
Grape Cultivars

Four French–American hybrid grape cultivars grown in a greenhouse were subjected to 5 days of 80% shade at four different times around bloom. Fruit set of `Seyval' was reduced by shade imposed before, during, or immediately after bloom. `Vidal' and `Chambourcin' were less sensitive, with fruit set reduced only by shade at bloom. Shade had little effect on fruit set of `DeChaunac'. In a second study, `Chambourcin' vines were exposed to ambient, ambient plus supplemental lights, and 30%, 50%, or 80% shade for 5 weeks beginning just prior to bloom. Fruit set was positively related to light intensity. At harvest, soluble solids, pH, and hue angle had a negative linear relationship to light level. Fruit color developed earliest and most rapidly with the reduced light treatments applied at bloom. Cluster weight was positively related to light intensity.

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