Xylem sap nitrogen compounds of some Crotalaria species

Abstract

Thirteen species of Crotalaria were analysed for nitrogen compounds in the xylem root bleeding sap. Amino acids were the main form of organic nitrogen found, but only traces of ureides were present. Of the four species analysed for amino acid composition, asparagine was found to be the major amino acid, accounting for over 68% of the nitrogen transported. No striking deviations from this general pattern was found between species, between vegetative and floral stages of development, or between nodulated and non-nodulated plants. It was concluded that the Crotalaria species studied here have an asparagine-based nitrogen metabolism, consistent with many other non-ureide-producing legume species.

Using amino‐nitrogen pools and fluxes to identify contributions of understoryAcaciaspp. to overstoryEucalyptus regnansand stand nitrogen uptake in temperate Australia

“…Quite a few reports contain estimates of the mass‐transport of N in xylem (Millard, 1996; Weber et al ., 1998; Vitória & Sodek, 1999; Peuke, 2000; Malaguti et al ., 2001; Frak et al ., 2002; Grassi et al ., 2002; Millard et al ., 2006; Nahm et al ., 2006a) but many are based on potted plants. Even so, mass flow of N is reported using a wide range of units.…”