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Abstract

Limbs of ‘Bing’ cherries (Prunus avium L.) were shaded with neutral density shade structures to reduce light levels to 10–15% full sun. Three placement times were used: a) petal fall to pit hardening (PF-PH), b) pit hardening to harvest (PH-H), and c) petal fall to harvest (PF-H). Shaded limbs had reduced fruit set, and fruit color and soluble solids were less in comparison to fruit from unshaded limbs. Fruit from shaded limbs were smaller than unshaded for the first 2 harvests, but for the last 2 harvest dates, fruit shaded from PF-PH or PF-H were larger. The time to reach dark red maturity was delayed 5 days by shading from PF-PH or PH-H and 12 days by shading from PF-H. When compared at equal color maturities, fruit from unshaded limbs were firmer than those from shaded limbs. In a study using natural shade, the relationship of fruit color and soluble solids to the percentage of full sun (FS) was logarithmic, with both variables dramatically reduced at light levels below 10–15% FS. Neither fruit weight nor firmness were related to the percentage of FS.

Open Access

The effects of temperature on flower size and number of flower buds of Campanula carpatica Jacq. 'Blue Clips', 'Deep Blue Clips', and Campanula 'Birch Hybrid' were investigated in four temperature and light-transfer experiments. In year 1, 'Blue Clips' and 'Birch Hybrid' plants were grown initially at 20 °C and then transferred at visible flower bud (VB) to 14, 17, 20, 23, or 26 °C until flower (Expt. 1). In Expt. 2, 'Blue Clips' and 'Birch Hybrid' plants were transferred from 14 to 26 °C or from 26 to 14 °C at various intervals after flower induction. Flower size of both species was negatively correlated with average daily temperature (ADT) after VB; flowers on plants grown at 14 °C were 35% larger than those on plants grown at 26 °C. In contrast, temperature before VB had only a small effect on final flower size in both species, although flower diameter of 'Birch Hybrid' plants grown at constant 26 °C was 20% smaller than that of the plants grown initially at 20°C and then transferred to VB to 26 °C. For both species, the longer the exposure to high temperature after VB, the smaller the flowers. Number of flower buds at flower in 'Birch Hybrid' decreased as ADT after VB increased. In year 2, 'Deep Blue Clips' plants were grown at constant 20 °C under high or low daily light integral (DLI, 17 or 5.7 mol·m-2·d-1) until VB, and then transferred to 14, 17, 20, 23, or 26 °C under high or low DLI (Expt. 3). In Expt. 4, 'Deep Blue Clips' plants were grown at 14, 17, 20, 23, or 26 °C until VB, and then transferred to constant 20 °C under high or low DLI until flower. Flower size (petal length) was negatively correlated with ADT both before and after VB, while flower bud number was negatively correlated with the ADT only after VB, regardless of DLI. In both experiments, petal length decreased by 0.3 to 0.5 mm per 1 °C increase in ADT before or after VB. Flowers were larger and more numerous under high than under low DLIs after VB, regardless of the DLI before VB.

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Mature `Macspur McIntosh'/MM.106 trees trained to the CL tree form were converted to the PL tree form in 1987 by removal of east- and west-oriented upper scaffold limbs. Control trees were pruned to maintain the CL form. Dormant pruning in later years maintained either tree form. No summer pruning was used in this study. Canopy light levels along horizontal transects at one m above the soil and vertical transects, both through the center of the canopy, were unaffected by tree form or transect direction. Yields were significantly lower for PL trees in 1987 and 1989, while yield efficiency was reduced in PL trees in all 3 years. Fruit size, trunk cross-sectional area, and foliar macro-nutrient content were unaffected by tree form during this study. Fruit color development in both the upper and lower halves of the canopy was uninfluenced by tree form.

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to decrease the time for rapid propagation of newly released cultivars. Axillary shoot proliferation and elongation can be enhanced by altering the spectral light quality of in vitro plantlets ( Chee and Pool, 1989 ; Economou and Read, 1987

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UVA or B light could be applied during production to increase lettuce quality and nutritional attributes and whether EOP UVA or B light is as effective at increasing lettuce phytonutrients and leaf pigmentation as applying UVA or B light during the

Open Access

hydroponic systems, and how light quality may affect cultivar growth and quality. In addition, how different combinations of red, blue, and green light affects hydroponically grown lettuce may facilitate the advancement of the controlled

Open Access

and shoot biomass. Specialty-crop species were chosen for this study based on economic value and to include variation in plant family, plant habit, and shade adaptation. Our objective was to quantify how seedlings grew and acclimated to light quality

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substituted by intracanopy light (ICL). Averages are based on three replicates of six plants per cultivar. Fruit quality. Cucumber fruits were longer when 33% of the supplemental light was provided by ICL compared with 100% top-light ( Table 3

Open Access

key time point for the experiment. Experimental design and treatments. The experiment was conducted as a 2 × 2 × 4 factorial (photoperiod × light quality × plant species) in a split-split-plot design with three replicates over time ( Table 1 ). The

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development. It is clear that light quantity and quality interact to determine plant morphology. The optimal light spectrum for plant growth and development likely changes with plant age as plant communities balance rapid leaf expansion necessary to maximize

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