TY - JOUR
AU - ATKINS, C., A.
AB - Abstract Nitrogen metabolism and transport were studied during reproductive development of cowpea (Vigna unguiculata (L.) Walp. cv. Vita 3) under three contrasting nitrogen regimes: (1) nitrate supplied continuously (plants non-nodulated), (2) symbiotic N2 fixation (no combined nitrogen), (3) nitrogenstarvation post-anthesis of previously N2-fixing plants. The last treatment involved daily flushing of the root systems with 100% oxygen which suppressed post-anthesis N2-fixation by 76–79%, thereby making fruit growth almost entirely reliant upon mobilization of previously accumulated nitrogen. The bulk of the xylem nitrogen (root bleeding sap or peduncle tracheal sap) of nitrate-fed plants was nitrate and amide, that of symbiotic and O2-treated plants largely ureide. The composition of fruit cryopuncture phloem sap, however, was closely similar in all treatments, with most nitrogen as amides and amino acids. The evidence suggested intense metabolic transfer of root derived nitrate-N or ureide-N to amino acids by vegetative plant parts prior to translocation to fruits. All tissues of fruits showed patterns of development of enzymic activities consistent with release of nitrogen from both ureides and amides and re-assimilation of ammonia to form amino acids. Although the levels of enzyme activities varied between treatments the differences could not be readily associated with individual patterns of nitrogen transport in the treatments. Nitrogen sufficiency in the NO3-fed plants was marked by elevated vegetative biomass and low harvest indices for dry matter and nitrogen, while nitrogen deficiency of the O2-treated plants was associated with seed abortion, small seed size and low seed nitrogen concentration, and efficient mobilization of nitrogen from vegetative parts to fruits. Nitrogen, Translocation, Cowpea This content is only available as a PDF. Author notes 1 Supported by grants from the Australian Research Grants Scheme and the Wheat Industry Research Council of Australia. © Oxford University Press
TI - The Effect of Nitrogen Source on Transport and Metabolism of Nitrogen in Fruiting Plants of Cowpea (Vigna unguiculata (L.) Walp.)
JF - Journal of Experimental Botany
DO - 10.1093/jxb/36.4.567
DA - 1985-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/the-effect-of-nitrogen-source-on-transport-and-metabolism-of-nitrogen-CLa871fI8C
SP - 567
EP - 582
VL - 36
IS - 4
DP - DeepDyve
ER -