Incandescent Radiation Research Articles

Light Inhibition of Nigella Germination: The Dependence of a High Irradiance Reaction on 720-nm Irradiance

Seeds of Nigella damascena L. germinated in darkness. Incandescent light inhibited germination, with greater inhibition occurring during the latter half of the 24-h imbibitional period. The inhibitory effects of incandescent radiation depended upon irradiance; inhibition of germination by a 12-h irradiation also exhibited a broad spectrum FR irradiance dependence. An action spectrum in the region of 650-740 nm revealed that 720-nm radiation was most inhibitory, suggesting that a HIR was operative. An action of P, evidenced by photoreversible control of germination following brief R and FR irradiations, was documented when temperature was shifted upward but not when temperature was held constant.

Radiation Environment of Growth Chambers1

Abstract Radiation measurements with different types of meters in several controlled environment facilities have been compiled to demonstrate the problems associated with insuring uniform radiation levels in separate faciities. Data are provided for a quantum meter, three photometers, a pyranometer and a far-red energy meter. Significant variations in total radiant energy in chambers under similar photosynthetically active radiation (PAR) levels were demonstrated. Measurement of light under cool white fluorescent and incandescent lighting with calibrated photometers from different manufacturers, varied by 20%. Greater variation occurred when photometer measurements were compared under different types of lamps. One of the most significant variations in different chambers was the intensity of incandescent radiation. This could only be effectively monitored and controlled with the far-red sensor. Factors are given for conversion between quantum, photometric and radiometric measurements, but high precision cannot be assumed in the use of these factors because of the differences in instrument sensitivity and variations in spectral output of lamps. The study documents the need for calibration of instruments under the same type of light source that is utilized in the growth chambers and for the use of more than one type of sensing instrument to quantify the radiation that controls plant growth.

Modified Photoelectric Device for Recording Leaf Movements

The description of a photoelectric device for monitoring leaf movements was published previously (5). This instrument eliminated physical attachment of sensors to the plant and provided a direct readout of up and down movements of leaves during light periods. The equipment has been modified to monitor rotational movements of the leaf about its longitudinal axis while simultaneously monitoring up and down movements. In addition, the servo-actuating incandescent radiation source has been replaced with a modulated infrared source to assure that radiation originating from the leaf monitor does not influence leaf movements and to permit the recording of leaf movements during periods of darkness, as well as during periods of light. Samples of recordings obtained with it are described.

Quality of Supplemental Lighting and Bulb Planting Depth on Development of Naturally Cooled Lilium longiflorum Thunb. ‘Harson’12

Abstract Four-hour dark period interruptions of incandescent, red and far-red radiation each night during natural cooling hastened flowering by 22, 15 and 8 days, respectively, over natural daylengths. No additional acceleration occurred when night breaks were applied during natural cooling and forcing as compared to lighting during natural cooling only. The accelerating effect of night breaks was found to be the response to light alone and not total radiant energy or temperature. Bloom date acceleration by night breaks of incandescent light was due to a proportionate acceleration in flower bud initiation. For every week of acceleration there was an average decrease of 2 flower buds and 7 leaves per stem. Bulb potting depth also influenced bloom date. The depth effects on flowering time were independent of lighting treatments. A 4-day acceleration was obtained by setting the bulb nose at the soil line as compared to a 2 inch planting depth. Plant height was independently influenced by photoperiod-light quality and by potting depth. Height was only slightly affected by supplemental lighting during natural cooling. After forcing temperatures were reached, red and incandescent lighting caused slight height increases while far-red caused pronounced stem stretching. Exposure of the bulb above the soil at potting reduced plant height at maturity.

Effects of a Single Biodose of Ultraviolet Radiation upon the Speed of College Women

Abstract The present study investigated the effects of a single suberythemic biodose on the speed of college women running the 30-yd. dash. Three trials were given on two consecutive days one hour after radiation. A double blind testing procedure was followed. Ultraviolet and incandescent radiation was alternated. Time was automatically recorded to .01 sec. A significant difference occurred in the third trial under the experimental condition. All other data favored the ultraviolet treatment but not significantly. It was concluded that a single biodose of ultraviolet radiation below threshold levels aids the speed of college women on the 30-yd. dash.

Part II: Assets and Deficiencies of Available Sources of Radiant Energy for Medical Uses: Practical Suggestions Regarding Sources of Radiant Energy for Medical Uses

The primary natural source of ultraviolet radiation is the sun. Approximately five per cent of this incandescent body's radiation is ultraviolet. The ultraviolet intensity at the earth's surface depends on a number of factors including time of day, time of year, latitude, elevation above sea level, atmospheric turbidity and thickness of the ozone layer.