accumulation in response to Mn nutrition by eight soybean genotypes with [N.
A 30- to 35-mg sample of dry ground leaf sample from each plot was used to determine shoot ureide
concentration using a modified colorimetric procedure (de Silva et al.
The procedure for ureide
analysis was as described by Young and Conway (1942) with minor modifications (Streeter, 1979).
Evaluation of the relative ureide
content of xylem sap as an indicator of [N.
Relative abundance of ureide
(RAU) was calculated from ureide
2] fixation sensitivity to water deficits opens the possibility of genotypic segregation based on ureide
2] fixation in Jackson to water deficits and have shown that leaf ureide
concentrations in Jackson are relatively low under water deficits (Serraj and Sinclair, 1996a; Purcell et al.
We tested the hypothesis that large nodules in combination with lower leaf ureide
levels would confer drought-tolerant [N.
2] fixation tolerance to soil-water deficit was the measurement of petiole ureide
levels under well-watered conditions.
2] fixation during water deficit was associated with ureide
accumulation in shoots.
Exceptions to this idea occur when urea is the chief cause of nitrogen supply, in species in which ureides
play an significant physiological role (Martin and Ruby, 2004), when too much application of Zn, Cu, Mn, Fe, Ca, or Mg has been made over many years (Martin and Ruby, 2004), and possibly also in nitrogen-fixing crops grown on mineral-poor or highly nickel-fixing (high pH, high lime) soils.
Concentrations of ureides
(allantion and allantoic acid) in xylem sap were measured as the phenylhydrazine derivative of glyoxylate (Young and Conway.