Source-sink relationships

Action of Vacuum on Spacecraft Materials. For service beyond the atmosphere, the vacuum environment allows materials to evaporate or decompose under the action of various forces encountered (1,18,19). These forces include the photons from the sun, charged particles from solar wind, and dust. The action of space environment on materials and spacecraft can be simulated by a source—sink relationship in a vacuum environment. Thus, for example, the lifetime of a solar panel in space operation may be tested (see Photovoltaic cells). 

This simulation can be achieved in terms of a source—sink relationship. Rather than use the gas concentration around the test object as a target parameter, the test object can be surrounded by a sink of ca 2-7T soHd angle. The solar panel is then maintained at its maximum operating temperature and irradiated by appropriate fluxes, such as those of photons. Molecules leaving the solar panel strike the sink and are not likely to come back to the panel. If some molecules return to the panel, proper instmmentation can determine this return as well as their departure rates from the panel as a function of location. The system may be considered in terms of sets of probabiUties associated with rates of change on surfaces and in bulk materials. 

Frankenberger, Jr., and Muhammad Arshad Handbook of Weed Management Systems, edited by Albert E. Smith Soil Sampling, Preparation, and Analysis, Kim H. Tan Soil Erosion, Conservation, and Rehabilitation, edited by Menachem Agassi Plant Roots The Hidden Half, Second Edition, Revised and Expanded, edited by Yoav Waisel, Amram Eshel, and Uzi Kafkafi Photoassimilate Distribution in Plants and Crops Source-Sink Relationships, edited by Eli Zamski and Arthur A. Schaffer Mass Spectrometry of Soils, edited by Thomas W. Boutton and Shinichi Yamasaki... 

Preiss J, Sivak MN. In Zamski E, Schaffer AA, eds. Photoassimilate Distribution in Plants and Crops Source-Sink Relationships. New York, NY Marcel Dekker 1996 63-96. 

Leegood, R. C. 1996. Primary photosynthetic production Physiology and metabolism. In Photoassimilate distribution in Plants and Crops. Source-Sink Relationships (E. Zam-sky, and A. A. Schaeffer, eds.), pp. 21—42. Marcel Dekker, New York. 

Zamski. E and Schaffer, A. A. 1996. Photoassimilate distribution in plants and crops. Source-sink relationships. Marcel Dekker, Inc. New York. 905 pp. 

Very little inter-plant transfer of or occurred from pea to barley in non-mycorrhizal systems with either intact plants or where the pea plants had their shoots removed. In mycorrhizal systems, significantly greater transfer occurred from decapitated pea plants (Fig. 3.4b). Whilst an elegant demonstration of such source sink relationships, this experimental design also suffered from the lack of reciprocal controls. Furthermore, an alternative mechanism for all such inter-plant transfer may simply be a more efficient uptake of elements liberated from donor plant roots by exudation or sloughing, by mycorrhizas associated with the receivers that are simply in the vicinity of the donor rhizosphere. None of the large number of inter-plant experiments reported actually discriminate between these alternative mechanisms. 

A book with many good reviews on source-sink relationships and factors affecting source-sink interactions... 

H. Ck)nclusions and Speculations Z+A retention, Photoinhibition, and Whole Plant Source-Sink Relationship... 

For most of the trace nitrogen compounds, the sources have increased significantly as a result of human activities. For some classes of compounds, such as NOx and NH3, humans ate the dominant source. ForN20, the human contribution is approximately 40% of the total. Nonetheless, because N2O is long lived, the human sources result in an imbalance in the global source-sink relationship and an ongoing increase in the tropospheric burden. 

Glyphosate is phloem mobile and accumulates in accordance with source-sink relationships in meristematic areas of the treated plants. " The general physiological effects of glyphosate are consistent with its acting as a metabolic poison. Death is a slow process, requiring days or weeks much more rapid effects, within hours, can be demonstrated at the biochemical level. These effects can be explained if the turnover rates of specific proteins, and therefore sensitivity to amino acid synthesis inhibition, differ. Inhibition of phenolic biosynthesis and chlorophyll formation and effects on the levels of the phytohormone 3-indoleacetic acid have been considered as target sites but can be viewed as necessary consequences of the primary interference with aromatic amino acid biosynthesis. " ... 

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