scholarly journals A PHOTOELECTRIC DEVICE FOR MEASUREMENT OF LEAF AREAS

1958 ◽  
Vol 38 (4) ◽  
pp. 490-494 ◽  
Author(s):  
L. S. Donovan ◽  
A. I. Magee ◽  
W. Kalbfleisch
Keyword(s):  
Light Source ◽  
Genetic Study ◽  
Red Light ◽  
Leaf Size ◽  
Light Filter ◽  
Birdsfoot Trefoil ◽  
Fluorescent Light ◽  
Photoelectric Device ◽  
Rapid Measurement

A device for the rapid measurement of leaf areas is described. Leaves are placed between a fluorescent light source, high in the red spectrum, and a photocell covered with an F29 red light filter. The reduction in output of the cell, as measured by a galvanometer, is interpreted in terms of area. The device has been successfully used in a genetic study of leaf size in birdsfoot trefoil.

scholarly journals INFLUENCE OF LIGHT SOURCE ON THE GROWTH OF ALFALFA CULTIVARS

1973 ◽  
Vol 53 (2) ◽  
pp. 291-294 ◽  
Author(s):  
D. H. HEINRICHS
Keyword(s):  
Protein Content ◽  
Light Source ◽  
Germ Plasm ◽  
Red Light ◽  
Fluorescent Light ◽  
Medicago Falcata ◽  
Definite Trend ◽  
Growth Room ◽  
Yellow Orange ◽  
Genetic Makeup

Alfalfa produced more herbage and more roots in a growth room when the fluorescent portion of an incandescent-fluorescent light source consisted of half gro-lux, high in blue-green-red light and half cool-white, high in blue-green-yellow-orange light than when it consisted of either alone. Protein content and degree of flowering were not affected by light source variations. Alfalfa cultivars, ranging in genetic makeup from Medicago falcata to M. media and M. sativa types, responded similarly to variations in light source. There was a definite trend for cultivars to produce less herbage and fewer roots as the proportion of M. falcata germ plasm in them increased. M. falcata flowered later than M. sativa in the growth room.

Effects of specific wavelength spectra on antioxidant stress and cell damage of the ornamental cleaner shrimp Lysmata amboinensis (De Man, 1888) (Decapoda, Caridea, Lysmatidae) exposed to changing saline environments

Crustaceana ◽  
2018 ◽  
Vol 91 (10) ◽  
pp. 1231-1245 ◽  
Author(s):  
Jong Ryeol Choe ◽  
Ji Yong Choi ◽  
Jin Ah Song ◽  
Cheol Young Choi
Keyword(s):  
Cell Damage ◽  
Red Light ◽  
Aquatic Organisms ◽  
Major Influence ◽  
Fluorescent Light ◽  
Saline Environments ◽  
Positive Effects ◽  
Negative Results ◽  
Antioxidant Stress ◽  
Cleaner Shrimp

Abstract A variety of environmental factors have a major influence on the survival of aquatic organisms, particularly light and salinity, changes in which lead to a range of physiological changes. In the present study, we investigated the levels of stress caused by changes in salinity in the ornamental cleaner shrimp, Lysmata amboinensis, as well as the effect of specific light wavelengths following stress to changes in salinity. We measured the activity of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) in the tissues (gill, hepatopancreas, and muscle) for three days after irradiating shrimp with specific wavelengths of light [red (630 nm), green (520 nm), and blue (455 nm)] at two intensities (0.5 and 1.0 W/m2) following exposure to different saline environments [25 practical salinity units (psu), 30 psu, 35 psu (normal seawater), and 40 psu]. DNA damage was measured using comet assays. Although all of the experimental groups exhibited negative results to changes in salinity, the green and red light groups exhibited positive effects when compared to the other wavelengths and fluorescent light. The effect of wavelength was not influenced by the intensity. In conclusion, the light of green and red wavelengths effectively reduces antioxidant stress and cell damage in cleaner shrimp.

scholarly journals The Effects of Day Length and Light Intensity on Tile Growth of Barley

1969 ◽  
Vol 22 (1) ◽  
pp. 53 ◽  
Author(s):  
D Aspinall
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Light Source ◽  
Blue Light ◽  
Floral Development ◽  
Red Light ◽  
Day Length

The acceleration of flowering in barley due to the inclusion of incandescent illumination in the light source has been shown to be due to the far�red content of the light. A linear relationship between floral development and intensity of far�red light in a 16�hr photoperiod has been established with the cultivar CI5611. Barley appears to be relatively unresponsive to blue light, however.

The value of red light at night for increasing basil yield

2018 ◽  
Vol 98 (6) ◽  
pp. 1321-1330
Author(s):  
Jaimin S. Patel ◽  
Leora Radetsky ◽  
Mark S. Rea
Keyword(s):  
Plant Height ◽  
Red Light ◽  
Leaf Size ◽  
Cost Effective ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light At Night ◽  
Sweet Basil

Sweet basil (Ocimum basilicum L.) is primarily used for culinary purposes, but it is also used in the fragrance and medicinal industries. In the last few years, global sweet basil production has been significantly impacted by downy mildew caused by Peronospora belbahrii Thines. Nighttime exposure to red light has been shown to inhibit sporulation of P. belbahrii. The objective of this study was to determine if nighttime exposure to red light from light-emitting diodes (λmax = 625 nm) could increase plant growth (plant height and leaf size) and yield (number and weight of leaves) in basil plants. In two sets of greenhouse experiments, red light was applied at a photosynthetic photon flux density of 60 μmol m−2 s−1 during the otherwise dark night for 10 h (from 2000 to 0600). The results demonstrate that exposure to red light at night can increase the number of basil leaves per plant, plant height, leaf size (length and width), and leaf fresh and dry weight compared with plants in darkness at night. The addition of incremental red light at night has the potential to be cost-effective for fresh organic basil production in controlled environments.

Tuning characteristics of fluorescent light source by dye-doped liquid crystal filled hollow fiber

2017 ◽  
Vol 66 (15) ◽  
pp. 154205
Author(s):  
L Yue-Lan ◽  
Yin Xiang-Bao ◽  
Yang Yue ◽  
Liu Yong-Jun ◽  
Yuan Li-Bo
Keyword(s):  
Liquid Crystal ◽  
Light Source ◽  
Hollow Fiber ◽  
Fluorescent Light
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