ISSN:
1573-5036
Keywords:
cowpea
;
nitrogen fixation
;
nitrate
;
partitioning
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract If the quality and quantity of yields from cowpea (Vigna unguiculata [L.] Walp.) are to be maximised, a complete understanding of the N nutrition of the plant must be achieved. The N requirement for developing pods of this species may come from mobilization of N in vegetative tissue, biological N fixation and uptake of N from soil. In this study, the fate of a pulse of fixed 15N2 or of 15NO3-given to different cowpea plants during pod development was determined. The plants were grown in vermiculite in plastic pots that were able to be sealed with silicone adhesive and equipped with a rubber septum so that 15N2 gas could be injected into the air space above the vermiculite, and gas losses would be eliminated. Nineteen days after injection of 15N2 the pods, leaves, nodules and roots contained 65%, 15%, 9%, and 4%, respectively of the quantity of 15N2 fixed. When 15NO3-15N was taken up by other plants during this period, these plant parts contained 40%, 26%, 3% and 19%, respectively, of the total plant 15N. The percentage 15N in roots was greater, and that of 15N in nodules was lower, when 15NO3-15N was applied than when 15N2 was utilised by plants. These results indicate that, while a high percentage of fixed-N or NO3-N given to cowpea plants moved to the developing pods, other sinks were competing for this newly-aquired N.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00025055
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