ISSN:
1573-5036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary If a nodulated legume is decapitated immediately after a brief period of photosynthesis in C14O2 a highly reproducible pattern of labelling is detected among the amino compounds of the root bleeding sap. The sequences of this pattern apparently reflect the consequences of the exchange of labelled carbohydrate with various morphological and metabolic compartments of the root. The progress of the exchange is greatly influenced by diurnal variations in root metabolism. An endogenous component is described for the rhythmic discharge of amino compounds into the bleeding sap. At 24°C the period of the rhythm is slightly greater than 24 hours. Plants with branched shoots are used to study environmental influences on the translocation of labelled assimilates from a shoot, and the utilisation of these materials in synthesis of organic compounds of nitrogen in the nodulated root. One half of the branched shoot is fed with C14O2 and its unlabelled partner removed for collection of bleeding sap. A progressive enrichment of bleeding sap with radiocarbon occurs only if the plants are exposed to normal photoperiods and ambient temperatures. Similar plants retained in darkness in constant temperature exhibit a rapid decline in the specific activity of the amino fraction of the bleeding sap, suggesting that translocation from the pool of labelled carbohydrate in the shoot has failed to keep pace with root synthesis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01373602
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