Search

Drop-covered surfaces in the landscape such as dew covers cause increased reflection of the incident light in a direction towards the light source, so-called retroreflection. Surveyable registration in the form of imagery of retroreflected light from pound surface and vegetation, for instance from an airplane, may provide valuable climatological and biological information. Different factors influencing the retroreflection are treated in the paper. Among these the lens-effect of the drops is dealt with in detail, and goniophotometric experiments with laser light are mentioned. An active remoteasensing system for registration of retroreflected light from drop-covered surfaces is described. The system Consists of a laser scanner equipped with an image-producing device. Laboratory tests with the apparatus are presented as well as planned activities with the equipment. [ABSTRACT FROM AUTHOR]

Filtrates from gametophyte cultures of Polypodium vulgare L. grown under red or blue light contain several substances affecting gametophyte development. Chromatograms prepared from red-light-grown cultures show two separate zones of inhibition while those from blue-light-grown cultures show a broad zone of promotive activity and a zone of inhibition. All the zones of activity affect spore germination, cell division and the transition to two-dimensional growth. None affects cell length but the inhibitors cause a reduction in cell width. Most of the known effects of red and blue light on gametophyte morphogenesis can be interpreted in terms of the activity of these substances. [ABSTRACT FROM AUTHOR]

At an in vivo level, thin-walled, ordinary colorless plants of H. emersonii increase more rapidly in size and have a longer generation time in the light than in the dark. Maximum stimulation occurs with continuous exposure to 100 foot candles of white light. The effective wave lights lie in the 400 to 500 mμ range. Atmospheric CO2 or 10-5 M bicarbonate are essential; without them, light has no effect. Preliminary data for a six-degree temperature range suggest that the Q10, for light-stimulated growth is unity. Finally, the effect of light can be duplicated by a mixture of glyoxylate and succinate, the presumed products of the reductive carboxylation of ketoglutarate which occurs in light-stimulated growth. At an in-vitro level, the effect of light on ketoglutarate metabolism is corroborated. In addition, the data suggest that another, unidentified reaction involving TPN and a product of glucose-6-phosphate metabolism is also affected by light. [ABSTRACT FROM AUTHOR]

The article discusses the effect of temperature and light intensity on the rate of apparent assimilation of Fucus serratus, using material that had been kept under standardized conditions during the pre-experimental period. Each of the specimens gathered were kept for 5 days in diffuse daylight, darkened for 12 hours on the night previous to experimentation, and subjected to the same degree of illumination prior to the experimental period. Winkler's method was used to determine the amount of dissolved oxygen given out by the plant over a known period of time.

Details are given of the design and construction of an apparatus used in conjunction with a spectroradiometer for the measurement of the chlorophyll content of leaves in vivo. [ABSTRACT FROM AUTHOR]

Presents a system for logging light interception in crop stands. Use of photosynthesis data for whole stands of plants in models simulating crop growth that requires an estimate of light intercepted by the canopy; Silicon solar cell fitted with a Jena BG-18 filter that is suitable for the purpose; Integration of transducer signals via resistance capacitance feedback networks utilizing operational amplifiers.

Describes several tests of a uranyl oxalate light integrator in relation to its applications in fruit tree canopies in an orchard. Evaluation of the distribution of light in the tree canopies that require many sensors and some form of integration of the short term values; Variability of light conditions in fruit tree canopies due to seasonal changes in growth and crop load; Implications on ecological studies.

Cites the key findings of a survey of apple orchard and tree structure together with measurements of light penetration and its effect on fruit quality. Two distinct types of apple orchard types that predominate the sector; Light penetration levels into the heterogeneous structure of apple orchards arising from the distance between apple trees and tree structure; Implications on ecological studies.

Recently, the substitution of conventional light sources for fluorescence microscopy by laser system have yielded promising results. The .system reported here is capable of creating fluorescent images by excitation with defined pulses of coherent light. Photographic recordings of fluorescent objects have been produced with exposures of less than 10 μsec. No significant amount of fluorescence bleaching was noted, even after illumination for 50 μsec. The laser light source holds a promise for improvement in microfluorometry, and is discussed with special reference to quantification in immunofluorescence. [ABSTRACT FROM AUTHOR]