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Tadahisa Higashide

et al., 1989 ). Hisaeda and Nishina (2007) reported that weekly tomato yields in a commercial greenhouse could be predicted from the cumulative solar radiation for a period from 8 to 1 weeks before harvesting. However, they predicted the yield only

Free access

Elio Jovicich, Daniel J. Cantliffe, Peter J. Stoffella, and Dorota Z. Haman

radiation can be used as a parameter to schedule irrigation events in soilless-grown plants, with adjustments of radiation set points (which initiate irrigation events) made based on plant growth stage and fruit load, solar radiation, temperature, or

Open access

G. Stanhill and J. Scholte Albers

Abstract

Measurements of global radiation above, and net solar radiation below, the roof of a glasshouse were both highly correlated on a daily and hourly basis with the water loss from a flowering rose crop as measured with a weighing lysimeter. The relationship can be used for an automatic system of irrigation control. Under local glasshouse, soil, and crop response conditions such a system would require an application of 6 liters of water per square meter of bed for every 730 cal cm2 global radiation above the glasshouse. Alternatively, a foliage spray irrigation system to ensure that the upper part of the canopy is kept continuously moist, would require applications of at least 0.4 liters per square meter at radiation intervals between 15 and 4 cal cm2 of global radiation outside the greenhouse, the exact figure depending mainly on the rate of air movement around the foliage. The latent heat equivalent of the crop water loss was 87% of the global radiation incident on the canopy, a figure similar to those listed for other, tall glasshouse crops.

Open access

William J. Sherry and Kenneth L. Goldsberry

Abstract

Dianthus caryophyllus L. cvs. DWF White #1, Scania and Crowley's Pink Sim were grown in greenhouses covered with new corrugated fiberglass reinforced plastic panels (New FRP), single layer UV-resistant polyethylene (Sgl Poly), air inflated double layer polyethylene (Dbl Poly), and 8-year-old weathered corrugated fiberglass reinforced plastic panels (Old FRP). Total flower production in the New FRP, Dbl Poly and Old FRP cover treatments was 1.9, 21.8 and 56.5% less, respectively, than in the Sgl Poly treatment. Significant interactions were noted between cultivar fresh weights, stem lengths, grades and cover treatment. Increase of irradiance in the cover treatments reduced return crop times while increasing stem length, fresh weight and grade.

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Thomas E. Marler and Patrick D. Lawton

Temperature and chlorophyll fluorescence characteristics were determined on leaves of various horticultural species following a dark adaptation period where dark adaptation cuvettes were shielded from or exposed to solar radiation. In one study, temperature of Swietenia mahagoni (L.) Jacq. leaflets within cuvettes increased from ≈36C to ≈50C during a 30-minute exposure to solar radiation. Alternatively, when the leaflets and cuvettes were shielded from solar radiation, leaflet temperature declined to 33C in 10 to 15 minutes. In a second study, 16 horticultural species exhibited a lower variable: maximum fluorescence (Fv: Fm) when cuvettes were exposed to solar radiation during the 30-minute dark adaptation than when cuvettes were shielded. In a third study with S. mahagoni, the influence of self-shielding the cuvettes by wrapping them with white tape, white paper, or aluminum foil on temperature and fluorescence was compared to exposing or shielding the entire leaflet and cuvette. All of the shielding methods reduced leaflet temperature and increased the Fv: Fm ratio compared to leaving cuvettes exposed. These results indicate that heat stress from direct exposure to solar radiation is a potential source of error when interpreting chlorophyll fluorescence measurements on intact leaves. Methods for moderating or minimizing radiation interception during dark adaptation are recommended.

Open access

Werner J. Lipton, Sharon J. Peterson, and Chien Yi Wang

Abstract

‘Honey Dew’ melon fruits (Cucumis melo L.) matured under filters that transmitted between 1% and 100% of total solar and between 2% and 100% of ultraviolet (UV) radiation. Solar yellowing (SY) developed predominantly on top of the melons and increased as their exposure to direct solar radiation increased. Degree of exposure to solar radiation during maturation and susceptibility to postharvest development of chilling injury (Cl) during 17 days at 2.5°C were inversely related. SY and Cl also were inversely related. Levels of ACC in the skin were low at harvest and unaffected by degree of exposure to solar radiation. Reducing the exposure to the sun by half nearly doubled the concentration of ACC during chilling; complete shading resulted in little additional increase in ACC. After chilling, the skin from the bottom of the melons consistently contained slightly more ACC than that from the top. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).

Open access

A. Erez and J. A. Flore

Abstract

‘Redhaven’ peach fruits were exposed to various durations of radiation at the end of stage II of fruit development. Exposure of only 3 days (totals about 6280 J·em−2) markedly stimulated anthocyanin development. Color development as a function of solar radiation followed a power curve with nearly maximal level obtained after 8 days of exposure (18,003 J·em−2). A similar response was obtained with shade screen (40% and 10% of full sun); the greater the shade the less red color developed. Shading fruit with aluminum foil resulted in softer fruit with a lower level of soluble solids as compared to control fruit. Fruit exposure to solar radiation therefore may have a direct effect on fruit sink activity.

Open access

Richard H. Mattson and Richard E. Widmer

Abstract

Cut flower yield of four greenhouse rose cultivars was primarily influenced by solar radiation, while atmospheric CO2, air temperature, and soil nutrient levels were of lesser importance. Cultivars responded differently to atmospheric CO2 level and soil fertilization method. Roses fertilized with 20-20-20 in solution produced equivalent or greater flower yields than roses fertilized with 10-10-10 in dry form. Roses grown in CO2 enriched atmospheres did not require additional soil fertilization.

Regression coefficients and yield prediction equations were determined using nine environmental parameters. Monthly yield predictions were generally reliable, but cropping cycles and cultural practices decreased accuracy.

Free access

Ken-ichiro Yasuba, Shigeki Furuya, and Hidekazu Sasaki

When we grow lettuce in the hot season in Japan, lettuce heads sometimes grow abnormally. In early autumn, we frequently find strange shapes of lettuce because of a projecting leaf midrib. Poorly shaped lettuce is unmarketable. We found that lettuce grew abnormally under the high temperature and low solar radiation conditions at the time of 1200 °C accumulative temperature from seeding (average temperature was >20 °C and daily total solar radiation was under 18 MJ/m2). Midribs of both good-shaped (resistance of projecting midrib) and poorly shaped cultivars projected this condition, but the symptom of the former was milder than that of the latter. So, we investigated the difference of leaf growth between good and poorly shaped cultivars using growth chambers. We set up six patterns of environmental conditions, which consisted of three patterns of temperature (30/22 °C, 24/16 °C, and 18/10 °C) and two patterns of light (4 and 2 MJ/m2). The two- to three-leaf seedlings, which were grown in the greenhouse for 27 days after sowing, were transplanted in the 250-mL pots and were carried to growth chambers. We measured width and length of each leaf 9 days after planting. Consequently, the ratio of width to length (w:l) of new leaves became low when we grew lettuce in high temperature or low light conditions. The w:l of good-shaped cultivars were higher than that of poorly shaped cultivars. Good-shaped cultivars did not grow spindly with ease on high temperature and low light conditions, like an early autumn environment. Now we will try to investigate the relationship between leaf shape and head shape on the poorly shaped conditions of some lettuce heads.

Open access

G. Stanhill, S. Moreshet, M. Jurgrau, and M. Fuchs

Abstract

The use of a highly reflecting layer of aluminized polyester to increase the amount of downward solar radiation in a rose glasshouse was investigated during midwinter. Solar radiation at the south end of the untreated glasshouse was 20% higher than that at the north end during this season, corresponding to similar differences in the number of flowers produced in mid-winter. Covering the north wall with a reflecting layer increased the solar radiations flux density above a roe crop canopy by 7.5% for about half the length of the cropped area. Covering the paths with the same material increased the downward solar radiation by an average of 3%, the effect being twice as great adjacent to the south wall. Much larger increases were inferred in the flux of upward solar radiation reaching the under surfaces of the canopy. Carbon dioxide fixation of the upper leaves of the rose canopy was linearly related to incident solar radiation. The effect of the reflecting surfaces on rose yield calculated from this relationship was in general agreement with that previously derived from the seasonal correlation between flower production and solar radiation.