Lighting for Greenhouse Vegetable Production – An Overview

Ehret, David L.; Molnar, J.; Jolliffe, P. A.

doi:10.4141/cjps89-159

Cited by 9 publications

(4 citation statements)

References 30 publications

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“…Shading increased nitrogen, potassium, phosphorus, and pigments in leaves, but there was less total carbohydrate (El Gizawy et al, 1993b). The use of supplemental light to increase radiation in a greenhouse had the opposite effect of decreasing potassium, but supplemental light increased calcium and magnesium (Ehret et al, 1989). We observed the concentrations of nitrogen and potassium increased in petioles, which may indicate higher concentrations of these elements mobilized in the plant.…”

Section: Discussionmentioning

confidence: 62%

Density and Duration of Shade Affect Water and Nutrient Use in Greenhouse Tomato

Gent¹

2008

J. Amer. Soc. Hort. Sci.

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Shading a greenhouse may have a time-dependent effect on fruit production and water and nutrient uptake in tomato plants (Solanum lycopersicum L.) as a result of acclimation to light and a dependence on stored carbohydrate and nutrients. In 2 years in the northeastern United States, shadecloth was applied at the start of warm weather in June and the houses were shaded until late August. Simultaneous comparisons were made among greenhouse sections that were either not shaded or covered with reflective aluminized shadecloth that blocked 0.15, 0.30, or 0.50 of direct sunlight. The amounts of water, nitrogen, and potassium taken up per day were calculated for successive 3-week intervals after shade was applied. The effect of shade on these uptake rates was compared with the effect on the rate of fruit production. There was a linear decline in water, nitrogen, and potassium uptake with increasing shade density. In each 3-week interval, water uptake under 0.5 shade density was 25% and 20% less than under no shade in 2004 and 2005, respectively. The uptake of nitrogen and potassium uptake under 0.5 shade density was ≈25% less than that under no shade. Shading did not affect the rate of fruit production within 3 weeks of application, but after more than 6 weeks, it was 30% less under 0.5 shade density than under no shade. The use efficiencies of radiation, water, and nutrients for fruit production increased with shade density immediately after shade were applied. These effects of shade on apparent resource use efficiencies dissipated from 3 to 6 weeks after shade was applied, because the effect of shade density on fruit production became proportionally the same as the effects on water and nutrient uptake. The water and nutrient uptake of greenhouse tomato acclimated to the change in irradiance resulting from shade within 3 weeks, but the full effect of shade on fruit production was not seen until 6 weeks after the application of shade.

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Section: Discussionmentioning

confidence: 62%

Density and Duration of Shade Affect Water and Nutrient Use in Greenhouse Tomato

Gent¹

2008

J. Amer. Soc. Hort. Sci.

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“…We wish to emphasize that the present study addressed the impact of different light spectra relevant for plant growth rather than killing of bacteria. Therefore, photosynthetically usable blue and red light bands with reasonable intensities and duration were employed, considering later application of the findings in terms of supplementary lighting in plant production [ 58 , 59 ]. However, if the deleterious molecular impact of different light regimes in microbial cells (production of reactive oxygen species (ROS)) is mediated by naturally occurring photosensitizers [ 56 , 57 ] with regards to both immediate microbial survival and long-term lifestyle changes, including changes in microbial communities, this might pave the way for novel strategies to fight bacterial infections.…”

Section: Discussionmentioning

confidence: 99%

Light spectrum modifies the utilization pattern of energy sources in Pseudomonas sp. DR 5-09

et al. 2017

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Despite the overruling impact of light in the phyllosphere, little is known regarding the influence of light spectra on non-phototrophic bacteria colonizing the leaf surface. We developed an in vitro method to study phenotypic profile responses of bacterial pure cultures to different bands of the visible light spectrum using monochromatic (blue: 460 nm; red: 660 nm) and polychromatic (white: 350–990 nm) LEDs, by modification and optimization of a protocol for the Phenotype MicroArray™ technique (Biolog Inc., CA, USA). The new protocol revealed high reproducibility of substrate utilization under all conditions tested. Challenging the non-phototrophic bacterium Pseudomonas sp. DR 5–09 with white, blue, and red light demonstrated that all light treatments affected the respiratory profile differently, with blue LED having the most decisive impact on substrate utilization by impairing respiration of 140 substrates. The respiratory activity was decreased on 23 and 42 substrates under red and white LEDs, respectively, while utilization of one, 16, and 20 substrates increased in the presence of red, blue, and white LEDs, respectively. Interestingly, on four substrates contrasting utilization patterns were found when the bacterium was exposed to different light spectra. Although non-phototrophic bacteria do not rely directly on light as an energy source, Pseudomonas sp. DR 5–09 changed its respiratory activity on various substrates differently when exposed to different lights. Thus, ability to sense and distinguish between different wavelengths even within the visible light spectrum must exist, and leads to differential regulation of substrate usage. With these results, we hypothesize that different light spectra might be a hitherto neglected key stimulus for changes in microbial lifestyle and habits of substrate usage by non-phototrophic phyllospheric microbiota, and thus might essentially stratify leaf microbiota composition and diversity.

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“…Screenhouses substantially modify the radiation regime with respect to the outside conditions, both quantitatively, through reduction of photosynthetic photon flux density (PPFD) reaching the crop, and qualitatively, through changes in the ratio of diffuse-todirect radiation (Healey et al, 1998) and the spectral distribution of solar radiation (Ehret et al, 1989;Kittas and Baille, 1999). With regard to open-field crops, the radiative microclimate under a screenhouse can lead to modifications in leaf physiological attributes and carbon allocation patterns, which in turn affects crop yield and quality Spigelman, 1986a, 1986b).…”

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confidence: 99%

Photosynthetic Acclimation of Sweet Pepper Plants to Screenhouse Conditions

Kitta

Katsoulas²,

Kandila³

et al. 2014

horts

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Leaf gas exchange and photosynthetic light acclimation of sweet pepper leaves were investigated in a Mediterranean area (central Greece) in the open field and in three screenhouse nets differing in color, shading intensity (SI), and porosity from May to Oct. 2011. The screenhouse nets were two insect-proof white nets (W13 and W34, SI = 13% and 34%, respectively) and a green shading net (G36, SI = 36%). Leaf net CO2 assimilation (An), transpiration rate (E), and stomatal conductance (gS) were measured by means of a portable gas exchange device on leaves located in three canopy layers. The differences in light regime within the canopy induced by the three shading nets had only a slight effect on An, thereby resulting in substantially higher light-use efficiency under shading than in the open field. The observed tendency toward higher gS in shaded plants was counterweighted by a lower intercellular-to-ambient CO2 concentration gradient, leading to similar An in leaves of shaded and non-shaded plants. Ontogenic effects (leaf aging) appeared to be the main factor determining the decreasing seasonal trend of leaf photosynthetic attributes. Overall, shaded sweet pepper plants display a physiological light acclimation allowing them to maintain the photosynthetic activity to a level similar to that observed in non-shaded plants across a wide range of growth light regimes, irrespective of the type of net and its shading intensity.

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Lighting for Greenhouse Vegetable Production – An Overview

Cited by 9 publications

References 30 publications

Density and Duration of Shade Affect Water and Nutrient Use in Greenhouse Tomato

Density and Duration of Shade Affect Water and Nutrient Use in Greenhouse Tomato

Light spectrum modifies the utilization pattern of energy sources in Pseudomonas sp. DR 5-09

Photosynthetic Acclimation of Sweet Pepper Plants to Screenhouse Conditions

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