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  • Author or Editor: Charles Fontanier x
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Objective methods of estimating green coverage using digital image analysis have been used increasingly by turfgrass scientists. The objective of our research was to evaluate the effectiveness of Canopeo, a relatively new smartphone application, for estimating green coverage of bermudagrass (Cynodon dactylon) emerging from winter dormancy, with or without colorants. A field study was conducted on a research ‘U3’ bermudagrass fairway in Stillwater, OK, during Spring 2019 and 2020. The experiment was conducted as a randomized complete block design with three colorant treatments: Endurant Fairway (FW), Endurant Perennial Ryegrass (PR), and an untreated control. Green coverage of the turfgrass canopy was determined weekly from mid-March to early May using a digital camera and ImageJ software, and a smartphone and the Canopeo application. Green coverage estimates from Canopeo correlated strongly (r = 0.91) with those from ImageJ when no colorants were applied. Correlation between Canopeo and ImageJ was diminished under plots treated with colorants. Canopeo is an effective tool for estimating green coverage of living turfgrasses, but additional calibration may be required for acceptable performance when evaluating greenness of colorant-treated turfgrasses.

Open Access

Rose cut flowers are popular in everyday bouquets or for special occasions, and tinting of the flowers by means of color addition increases the flowers economical value and aesthetic appeal. This study evaluated red and white luminescent rose cut flowers, which was achieved by applying six persistent luminescent powders. Solutions of each color were prepared by mixing 6 g of powder and 240 ml of deionized water and sprayed four times around the flower head plus a control. Images were taken of the flowers before ultraviolet blacklight exposure and after exposure to be later analyzed with ImageJ software. Daily measurements were taken including vase weight, average floral diameter, and visual deterioration based on scale of 1 to 4. Overall measurements included mean brightness; red, green, and blue measured values; dominant wavelengths of emitted color; flower diameter change rate; relative water percent; solution uptake rate; and vase solution uptake rate. For luminescent brightness mean without ultraviolet, white rose with blue powder had the greatest value. For luminescent brightness after ultraviolet exposure, white rose with green powder had the greatest value. With ultraviolet exposure, white roses with green powder had the greatest value followed by blue, orange, and white. Red powder on white and red roses experienced little to no luminescence before or after ultraviolet exposure. Mean and mode varied in their calculated dominant wavelengths; therefore, it is recommended to use mean values because more similarities in matching of the powder color and the calculated dominant wavelength were reported. Ultimately, white roses are preferred because they seemed to have greater health and luminescence compared with red roses, and green and blue powder would be recommended for luminescent application for brightness.

Open Access

An experiment was conducted to quantify luminescence of white cut flower carnations after exposure to blue glow-in-the-dark powder. Powder was applied to the flowers as either dip (3, 6, or 9 g) or spray (3, 6, or 9 g) solutions in 240 mL of water for 4 seconds plus a control. Stem fresh weight, relative stem fresh weight, flower diameter, and overall solution absorption were greatest on day 4. Only the 6-g dip or spray had greater average flower quality ratings than the control, indicating reduced vase life, but there was no difference among powder treatments. Phosphorescence is possible with fluorescent light, but ultraviolet light increased the flower mean brightness an average of 75% across all treatments. No treatment differences were observed for the flower mean brightness with ultraviolet light, except on day 9; however, greater powder rates without ultraviolet light in general resulted in greater brightness.

Open Access

The color of horticultural shade nets is known to influence crop growth and quality because of variations in the amount and quality of light. Four ornamental plant species (celosia, begonia, gerbera, and fountain grass) were grown under aluminet, pearl, and red shade nets plus black as the control at 50% shade intensity for 8 weeks. Black had the least transmittance (∼10% to 30% of ambient) within the red spectrum (620–750 nm), whereas red had the greatest at ∼70% to 80%. Aluminet and pearl resulted in a similar reduction in photosynthetic photon flux at ∼50% to 55% and ∼55% to 65% of ambient, respectively. Aluminet increased the shoot dry weight for begonia and celosia, whereas no differences among shade nets were seen for gerbera or fountain grass. The chlorophyll concentration was greatest under aluminet for each species except begonia. Shade net color did not affect flower number.

Open Access

Increase in ambient carbon dioxide (CO2) concentration is beneficial for plant growth due to increased photosynthesis and water use efficiency. A greenhouse study was conducted to investigate how supplemented CO2 influences optimal irrigation and fertilization management for production of two ornamental plants. Two identical greenhouses were used, with one having CO2 supplementation and the other serving as the control with ambient CO2 concentration. Tensiometer-based irrigation treatments were applied at soil tensions of –5, –10, and –15 kPa with 0-, 3-, 6-, or 9-g controlled-release fertilizer rates applied in factorial with irrigation treatments. Plugs of geranium ‘Pinto Premium Rose Bicolor’ and fountain grass were grown under experimental conditions for 12 and 16 weeks, respectively. The results showed that CO2 supplementation increased the dry weight of geranium ‘Pinto Premium Rose Bicolor’ and fountain grass by 35% and 39%, respectively. Under the two driest irrigation regimes (–10 and –15 kPa), photosynthesis of geranium ‘Pinto Premium Rose Bicolor’ increased with CO2 supplementation compared with the ambient condition. Similarly, for fountain grass, the moderately watered (–10 kPa) treatment had a greater rate of photosynthesis with greater fertilizer rates of 6 or 9 g. CO2 supplementation resulted in increased water use efficiency of both species, whereas rate of transpiration was lower only in fountain grass. Among different fertilizer rates, 6- or 9-g fertilizer rates had greater values for dry weight, number of flowers, and stomatal conductance in both species. Therefore, it can be concluded that CO2 supplementation can help in efficient use of water for greenhouse production of ornamental plants.

Open Access

Landscape irrigation frequency restrictions are commonly imposed by water purveyors and municipalities to curtail domestic water use and to ensure adequate water supplies for growing populations during times of drought. Currently, published data are lacking concerning irrigation frequency requirements necessary for sustaining acceptable levels of turfgrass quality of commonly used warm-season turfgrass species. The objective of this 3-year field study was to determine comparative turfgrass quality of drought-resistant cultivars of four warm-season lawn species in the south–central United States under irrigation frequency regimes of 0, 1, 2, 4, and 8× monthly. Turfgrasses used in the study were based on previously reported drought resistance and included ‘Riley’s Super Sport’ (Celebration®) bermudagrass [Cynodon dactylon (L.) Pers.], ‘Palisades’ zoysiagrass (Zoysia japonica Steud.), ‘Floratam’ st. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and ‘SeaStar’ seashore paspalum (Paspalum vaginatum Swartz). During each growing season, slightly reduced irrigation volumes and bypassed events resulted from the 8× monthly treatment (34.95 cm, 38.13 cm, and 27.33 cm) compared with the 4× monthly treatment (35.36 cm, 40.84 cm, and 28.70 cm) in years 1, 2, and 3, respectively. For the once weekly treatment, the average fraction of reference evapotranspiration (ETo) supplied by effective rainfall and irrigation during the summer months was 1.22, 0.67, and 0.83 in years 1, 2, and 3, respectively, and was generally adequate to support acceptable turfgrass quality of all warm-season turfgrasses evaluated. Under the less than weekly irrigation frequency, st. augustinegrass and seashore paspalum generally fell to below acceptable quality levels because the average fraction of ETo supplied by effective rainfall and irrigation during the summer months of years 2 and 3 was 0.51, 0.39, and 0.26 for the 2× monthly, 1× monthly, and unirrigated treatments, respectively. Bermudagrass generally outperformed all other species under the most restrictive irrigation frequencies and also did not differ statistically from zoysiagrass. These results show that as irrigation frequency is restricted to less than once per week, species selection becomes an important consideration.

Open Access

Success of the floral industry lies in strengthening the fresh flower market with value-added products. An experiment was conducted to quantify luminescence of cut-flower white carnations after exposure to two fluorescent products (dye from a yellow highlighter or glow-in-the-dark spray paint). Single stems were placed in bud vases that were filled with 240 mL deionized water and 2 g floral preservative. Highlighter treatments were applied to the vase as either one drop, three drops, or half of the dye reservoir (half stick). Paint treatments were applied at 2-, 4-, or 6-second durations to the flowers. Combination treatments were applied as three drops of highlighter dye plus either 2, 4, or 6 seconds of paint application. Treatments were compared against each other and a nontreated control. There were five repetitions of three stems per treatment arranged in a completely randomized design. Measurements were taken daily on stem fresh weight, flower diameter, quality rating, flower maximum brightness, flower mean brightness, relative stem fresh weight percentage, overall solution absorption rate percentage, and daily solution absorption rate. Stem fresh weight, relative stem fresh weight percentage, flower diameter, and overall solution absorption rate were greatest on day 4. Flower maximum brightness without ultraviolet (UV) light was greatest 2 days after treatment (DAT), but still produced a detectable glow through 8 DAT. Among treatments before UV charge, the 6-second paint duration provided the greatest flower maximum brightness value. The half-stick highlighter treatment had the greatest vase mean brightness. All paint treatments reduced flower quality. For each treated flower, the UV charge increased the brightness values, which ranged from 53% to 206% greater than before the UV charge. White carnations can luminesce with spray applications of glow-in-the-dark spray paint or through the stem absorption method using yellow highlighter dye, with the latter being less detrimental to vase life but requiring a UV light source to glow.

Open Access

Water temperature can affect plant growth and quality in hydroponic production. Lettuce ‘Antonet’, ‘Waldman’s Dark Green’, ‘Parris Island’, ‘Jericho’, and ‘Rex’ were grown using the nutrient film technique with chilled (water temperature set at 21.1 °C) or ambient water. Data were collected on plant growth, foliar nutrient content, and vitamin A content. ‘Jericho’ had the greatest shoot fresh weight but was only significantly different from ‘Antonet’, which had the lowest shoot fresh weight but the greatest vitamin A content. SPAD was greatest in ‘Paris Island’ and was significantly greater in chilled water over ambient for ‘Antonet’. Plants grown in ambient water had greater number of leaves and root dry weight, whereas SPAD was greatest with chilled water. Greater nutrient values were observed in ‘Rex’, ‘Jericho’, and ‘Waldman’s Dark Green’ in chilled water, whereas no nutrient differences were observed in ‘Antonet’ and ‘Parris Island’.

Open Access

Colored shade nets are known to alter the light quality and quantity and thus can influence plant growth and nutritional quality of crops. Lettuce (‘Lollo Antonet’ and ‘Green Forest’) and basil (‘Aroma-2’ and ‘Genovese’) were grown in ebb-and-flow hydroponic tables for 4 weeks. Colored shade nets of aluminet, black, pearl, and red with 50% shading intensity along with a control (no-shade) were used in this experiment. Data for plant growth and leaf quality attributes were collected at harvest time. The no-shade treatment showed increased shoot fresh and dry weight, sugar, and relative chlorophyll content in both lettuce and basil cultivars, whereas plant height and net photosynthesis rates were increased under aluminet, pearl, and red nets. In basil, calcium and sulfur were greatest under no-shade, whereas zinc and copper were greatest under aluminet. Zinc, iron, calcium, magnesium, and manganese concentrations were greatest under no-shade in lettuce. The pearl-colored net increased leaf soluble solids content. No-shade produced the greatest starch values in basil, whereas pearl shade net produced the greatest starch in ‘Lollo Antonet’ in the fall. Light spectra varied with shade net resulting in 90%, 65%, 50%, 30%, and 70% of incident light occurring between 400 and 700 nm for no-shade, pearl, aluminet, black, and red shade nets, respectively. Overall, lettuce and basil plants under no-shade (daily light integral of 20 to 24 mol·m−2·d−1 and temperature of 26 to 30 °C) had increased plant growth and leaf quality in late spring and fall, compared with colored shade nets.

Open Access

Cell and plastid membranes play a critical role in plant response to chilling stress. Fall color retention (chilling tolerance) of bermudagrass (Cynodon sp.) is known to vary with cultivar and management practices. A growth chamber study was conducted to characterize the lipid composition of three bermudagrasses in response to chilling stress. The grasses selected were ‘Tahoma 31’ (chilling-sensitive) and ‘Tifway’ (chilling-tolerant) interspecific hybrid bermudagrass (C. dactylon × C. transvaalensis) and ‘Celebration’ common bermudagrass (C. dactylon), which served as an internal standard. Plants were subjected to simulated fall conditions defined as an 8/2 °C (day/night) temperature regime with 10-hour photoperiod and evaluated for chilling response for 42 days before allowing plants to enter an apparent dormancy. Plant leaves were sampled for lipidomics analysis at 0, 14, and 42 days of chilling treatment (DOT) and again after 40 days of recovery from dormancy (during which temperatures were adjusted to mimic average spring conditions for Oklahoma). ‘Tifway’ demonstrated the lowest electrolyte leakage (EL) and visual discoloration at 42 DOT, while ‘Tahoma 31’ had the greatest EL and discoloration on the same date, and ‘Celebration’ was intermediate of the two. Prolonged exposure to chilling stress generally increased digalactosyldiacylglycerol and phosphatidylcholine (PC) content and decreased monogalactosyldiacylglycerol (MGDG) content, with ‘Tahoma 31’ showing the greatest increase in PC and decrease in MGDG. The double bond index, an indicator of fatty acid unsaturation, was greatest in ‘Tifway’ at 42 DOT. Each cultivar increased in fatty acid unsaturation, with Tifway demonstrating the greatest increase in MGDG unsaturation. Multivariate discriminant analysis identified six individual lipid species that contributed most to the cultivar response to chilling. These findings suggest unsaturation level of plastid lipids, particularly MGDG, is important for chilling tolerance and therefore fall color retention of bermudagrass. Furthermore, this study provides evidence that chilling tolerance can be negatively associated with freezing tolerance in bermudagrass.

Open Access