Inter- and intra-species differences in nitrate uptake and N allocation were studied in wheat seedlings. Two collections of wheat cultivars Triticum aestivum and Triticum durum were grown at controlled conditions in hydroponics (773µM NO<sub>3</sub><sup>–</sup>, i.e. 10.8 ppm N-NO<sub>3</sub><sup>–</sup>). At the age of 3 weeks the net rate of nitrate uptake was measured in depletion experiments and it was expressed as µmol NO<sub>3</sub><sup>– </sup>per g of root fresh weight per hour (µmol/g FW/h). Nitrate uptake capacity of the whole root system was expressed as µmol NO<sub>3</sub><sup>– </sup>per plantper hour (µmol/plant/h). At the same time wheat plants were harvested and analyzed for nitrogen content. In contrast to the net rate of NO<sub>3</sub><sup>– </sup>uptake (3.98–8.57 µmol/g FW/h) the net NO<sub>3</sub><sup>– </sup>uptake capacity of T. aestivum roots (6.37–11.66 µmol/plant/h) significantly differed from T. durum roots (15.26–22.69 µmol/plant/h). Within T. aestivum collection cultivar Roxo exhibits the lowest value in both traits (3.98 µmol NO<sub>3</sub><sup>–</sup>/g FW/h and 6.67 µmol NO<sub>3</sub><sup>–</sup>/plant/h). By contrast Strela was characterized by relatively low NO<sub>3</sub><sup>– </sup>uptake rate (5.47 µmol/g FW/h) and the highest NO<sub>3</sub><sup>– </sup>uptake capacity (11.66 µmol/plant/h). Intra-species differences in T. durum group were not significant. In both species about 70% total nitrogen was found in shoot. Statistically significant differences in nitrogen content and its allocation were affected by growth rate in early stages of development.
Cation Pretreatment Effects on Nitrate Uptake, Xylem Exudate, and Malate Levels in Wheat Seedlings
