References

162 T. Müller, W. Koch, D. Wipf
Fig.11.3. Phylogenetic tree of the ATF1 superfamily. Maximum parsimony analyses were
performed using PAUP 4.0b10 (Swofford 1998). Heuristic tree searches were executed using
100 random sequence additions and the tree bisection-reconnection branch-swapping
algorithm with random sequence analysis. The complete alignment was based on 529 sites;
498 were phylogenetically informative. Bootstrap values (%) are indicated at branch nodes
nitrogen, these transporters have Km values that are in a physiological
range with respect to the concentrations of these AA found in the phloem
and xylem. Aspartate is transported by most AAP with an extremely low
affinity and efficiency. Only AAP6 has a Km valueforaspartatethatisin
a physiological range (Fischer et al. 2002).
Plants take up nitrate and ammonium but also AA as a nitrogen source
and, more importantly, AA are the principal long-distance transport forms
of organic nitrogen. In accordance with these facts, reporter gene analyses