Nitrate accumulation, productivity and photosynthesis of Brassica alboglabra grown under low light with supplemental LED lighting in the tropical greenhouse

2019 ◽  
Vol 42 (15) ◽  
pp. 1740-1749 ◽  
Author(s):  
Jie He ◽  
Lin Qin ◽  
Li Jun Lilian Teo ◽  
Choong Tsui Wei
2015 ◽  
Vol 33 (4) ◽  
pp. 428-433
Author(s):  
Nezihe Koksal ◽  
Meral Incesu ◽  
Ahmet Teke

ABSTRACT: Pansy (Viola cornuta) is a facultative long-day plant that flowers from October until March in Turkey. During the winter months, low light levels can limit plant growth and development. Light emitting diodes (LEDs) can provide supplemental lighting in greenhouses which produce same light intensity with less energy than conventional incandescent lighting. Light emitting diode technologies have enabled affordable and efficient light systems to be installed in greenhouses and plastic tunnels in the field. In this experiment we evaluated the effects of supplemental red-orange LED lightening on the growth and development of pansy cv. Blue Blotch grown in plastic tunnels. The energy, which LEDs are to consume, was provided through a solar panel system with the aim of drawing attention to the cleanliness of solar energy source. Five hours of supplement LED lighting was applied after dusk starting from November to February. Pansy growth and development parameters were compared with non-light supplied control plants. Supplemental LED lighting significantly increased plant biomass weight, flower number and leaves number at the rate of 52%, 72%, and 47%, respectively. Moreover, LED lighting increased plant growth rate (0.109 and 0.306 g of fresh weight), compared with the no light control. LED lighting, however, had no effect on length of stems, number of branches and the diameter of flowers. Thus, this study indicated that pansies are light limited during the winter months and supplemental LED lighting can significantly increase pansy growth and development.


2004 ◽  
Vol 129 (4) ◽  
pp. 570-575 ◽  
Author(s):  
Jernej Demšar ◽  
Jože Osvald ◽  
Dominik Vodnik

With a high nitrate supply, and most frequently under low-light conditions, lettuce accumulates relatively large amounts of NO3-as a result of an excess of uptake over reduction. Different approaches, which are used to reduce leaf nitrate, often result in a yield loss. A computerized aeroponic system, which supplies different nitrate concentrations in accordance with the changeable light conditions (dynamic light-dependent application of nitrate), was used to reduce nitrate accumulation in lettuce (Lactuca sativa L.) var. Capitata cv. Vanity. Under unfavorable light conditions nitrate was supplied at limited rates (slight, medium, and strong reduction) to the plants. In response to given light conditions the nitrate supply was reduced close to one-half or one-fourth of the full nutrient solution (8 mmol·L-1 NO3-). Controlled nutrition resulted in efficient reduction in leaf nitrate. In the early-spring experiment the average nitrate content in outer leaves was decreased by 9%, 63%, and 92% and in the late-spring experiment the decrease was 23%, 58%, and 76% compared to control. At the same time, the controlled, light-dependent nitrate deprivation did not result in a loss of a lettuce yield (except in the treatment with strong nitrate reduction) and had limited effects on photosynthesis (PN-Ci measurements) and photosynthetic pigments.


Author(s):  
N.S. Bolan ◽  
P.D. Kemp

Although plant roots take up nitrogen (N) both as ammonium (NH4 +) and nitrate (NO3 -) ions, under most soil conditions uptake of NO3 - dominates. Once absorbed by the plant roots, the NO3 - is reduced to NH4 +, which is subsequently assimilated into organic compounds. However, when the rate of uptake exceeds the rate of NO3 - reduction, accumulation of NO3 - in plants occurs. Ruminant animals with high NO3 - levels in their diets accumulate nitrite (NO2 -). Nitrite is absorbed into the blood and combines with hemoglobin to form methemoglobin. This condition is known as nitrate poisoning (i.e., methemoglobinaemea). Nitrate poisoning occurs when animals eat forage material with high NO3 - content. The most common causes of high NO3 - content in forage tissue include: (i) high application of N fertilizers; (ii) drought conditions; (iii) damage to plant tissue (such as defoliation as a result of herbicide application); (iv) low light intensity, which reduce photosynthetic activity; and (v) presence of NO3 - accumulating plant species, such as annual weeds. In this review paper, the processes of uptake and assimilation of N by plants, factors affecting NO3 - accumulation in plants, and the treatment and prevention of nitrate poisoning in grazing animals are discussed. Keywords: forage crops, methemoglobinaemea, methylene blue, N fer tilizer, nitrate accumulation, nitrate poisoning, nitrate reductase


1974 ◽  
Vol 54 (4) ◽  
pp. 783-788 ◽  
Author(s):  
D. J. CANTLIFFE ◽  
S. C. PHATAK

Four cultivars each of lettuce (Lactuca sativa L.), radish (Raphanus sativa L.) and spinach (Spinacia oleracea L.) were grown at three NH4NO3 levels (0, 14.7 and 29.4 g N/m2) in a muck soil as a commercial greenhouse crop under winter conditions (low light intensity and short photoperiod). Analysis of the tissues for NO3-N showed that all three vegetable crops contained high concentrations of NO3-N when grown under these conditions: radish highest, followed by lettuce, then spinach. Total N and NO3-N were increased by N fertilizer only in radish roots, and yield was promoted by the additional N only in lettuce. Lettuce cultivars Domineer and Korrekt contained significantly less NO3 than Grand Rapids or Noran and were higher yielding than the standard cultivar Grand Rapids. The NO3 content of radishes was extremely high, especially in the root of the white cultivar Icicle (1.68% NO3-N). Yield of roots from Icicle was not significantly different from Champion, Early Scarlet Globe and Red Boy, cultivars which did not contain as much NO3-N. Smooth-leaf spinach cultivar Northland was higher yielding with significantly less NO3 than savoyed cultivars America, Winter Bloomsdale or Savoy. High NO3 tissue concentrations can be reduced in these crops by growing cultivars that accumulate less NO3.


Author(s):  
G.Y. Fan ◽  
J.M. Cowley

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.


Author(s):  
W. Lin ◽  
J. Gregorio ◽  
T.J. Holmes ◽  
D. H. Szarowski ◽  
J.N. Turner

A low-light level video microscope with long working distance objective lenses has been built as part of our integrated three-dimensional (3-D) light microscopy workstation (Fig. 1). It allows the observation of living specimens under sufficiently low light illumination that no significant photobleaching or alternation of specimen physiology is produced. The improved image quality, depth discrimination and 3-D reconstruction provides a versatile intermediate resolution system that replaces the commonly used dissection microscope for initial image recording and positioning of microelectrodes for neurobiology. A 3-D image is displayed on-line to guide the execution of complex experiments. An image composed of 40 optical sections requires 7 minutes to process and display a stereo pair.The low-light level video microscope utilizes long working distance objective lenses from Mitutoyo (10X, 0.28NA, 37 mm working distance; 20X, 0.42NA, 20 mm working distance; 50X, 0.42NA, 20 mm working distance). They provide enough working distance to allow the placement of microelectrodes in the specimen.


Author(s):  
Ray Keller

The amphibian embryo offers advantages of size, availability, and ease of use with both microsurgical and molecular methods in the analysis of fundamental developmental and cell biological problems. However, conventional wisdom holds that the opacity of this embryo limits the use of methods in optical microscopy to resolve the cell motility underlying the major shape-generating processes in early development.These difficulties have been circumvented by refining and adapting several methods. First, methods of explanting and culturing tissues were developed that expose the deep, nonepithelial cells, as well as the superficial epithelial cells, to the view of the microscope. Second, low angle epi-illumination with video image processing and recording was used to follow patterns of cell movement in large populations of cells. Lastly, cells were labeled with vital, fluorescent dyes, and their behavior recorded, using low-light, fluorescence microscopy and image processing. Using these methods, the details of the cellular protrusive activity that drives the powerful convergence (narrowing)


2019 ◽  
pp. 71-77
Author(s):  
Vladimir V. Vorozhikhin ◽  
Eugenia L. Moreva ◽  
Vladimir G. Starovoytov ◽  
Igor G. Tyutyunnik

The purpose of this paper is an investigation of LEDs illumination experience at US-based aerodromes with an assessment of its feasibility and its necessity in Russia. The following methods were used: the analysis of aerodrome lighting requirements; the review and the analysis of development features in aerodrome LEDs illumination; the experience analysis of LEDs illumination of US-based aerodromes; the deductive analysis and the assessment synthesis of feasibility and necessity of US experience in LEDs illumination at Russian-based aerodromes. The following results were achieved: – The analysis of issues and opportunities was conducted for development of LEDs illumination at US-based aerodromes and of American experts’ recommendations for its use; – The cases were taken for use and assessment of development in LEDs illumination at US-based aerodromes; – The review and the analysis were conducted in relation to a developing market of LEDs illumination at Russian-based aerodromes. The main conclusion is that the US experience will improve quality and reliability of service provided in air transportation, comfort, and safety of Russian flights, as well as competitiveness of Russian- based airports and airlines (indirectly).


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