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Plant Physiology 70:476-482 (1982) © 1982 American Society of Plant Biologists Metabolism and Translocation of Allantoin in Ureide-Producing Grain Legumes 1Botany Department, University of Western Australia, Nedlands 6009, Western Australia, Australia
Transfer of the nitrogen and carbon of allantoin to amino acids and protein of leaflets, stems and petioles, apices, peduncles, pods, and seeds of detached shoots of nodulated cowpea (Vigna unguiculata L. Walp. cv. Caloona) plants was demonstrated following supply of [2-14C], [1,3-15N]allantoin in the transpiration stream. Throughout vegetative and reproductive growth all plant organs showed significant ureolytic activity and readily metabolized [2-14C]allantoin to 14CO2. A metabolic pathway for ureide nitrogen utilization via allantoic acid, urea, and ammonia was indicated. Levels of ureolytic activity in extracts from leaves and roots of nodulated cowpea were consistently maintained at higher levels than in non-nodulated, NO3 grown plants. [14C]Ureides were recovered in extracts of aphids (Aphis craccivora and Macrosiphum euphorbieae) feeding at different sites on cowpea plants supplied with [2-14C]allantoin through the transpiration stream or to the upper surface of single leaflets. The data indicated that the ureides were effectively transferred from xylem or leaf mesophyll to phloem, and then translocated in phloem to fruits, apices, and roots.
1 Supported by grants from the Australian Research Grants Committee and the United Nations Development Program through a cooperative project with the International Institute of Tropical Agriculture, Ibadan, Nigeria. This article has been cited by other articles:
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