Ammonium and nitrate are both suitable inorganic nitrogen forms for the highly productive wetland grass Arundo donax, a candidate species for wetland paludiculture

作者：Bui Truong Tho^*; Lambertini Carla; Eller Franziska; Brix Hans; Sorrell Brian K

来源：Ecological Engineering, 2017, 105: 379-386.

DOI：10.1016/j.ecoleng.2017:04.054

• Giant reed
• Photosynthesis
• Nitrate reductase activity
• Uptake velocity
• Leaf biochemistry
• Paludiculture
• Inorganic nitrogen
• Biomass

The effects of inorganic nitrogen (N) forms (NH4+, NO3- or both) at equimolar (0.5 mM) concentrations on growth, biomass allocation, photosynthesis, nitrate reductase activity (NRA) and N uptake rates of Arundo donax were investigated in hydroponic culture. Plants supplied with NH4+, or NH4NO3 had significantly higher above -ground biomass, leaf length, shoot number and shoot production rates than NO3- fed plants, whereas the relative growth rates, below -ground biomass, and other plant morphological parameters were indifferent to N nutrition. Leaf photosynthetic pigment concentrations and leaf specific area of NO3-fed plants were lower than those of plants grown on NH4+, or NH4NO3. In addition, NH4+ and NH4NO3 fed plants had higher light -saturated rate of photosynthesis and stomatal conductance than NO3- fed plants and there were no differences in leaf dark respiration among N -form treatments. Both leaves and roots of A. donax had NRA, but NRA was much greater in leaves, particularly when plants were fed with NO3-. The N uptake rate of A. donax was greatest when supplied as NH4NO3 (1.10+ 0.34 mg N g-lroot DM h(-1)) although not different from the N uptake rate with NH4+ alone (0.61 +0.08 mg N g(-1) root DM h(-1)), whilst NO3- uptake velocities were similar among N -form treatments. Our results indicate that although some traits perform better in the presence of NH4+ presumably due to lower energetic costs of NH4+ uptake, A. donax grows well with either NH4* or NO3-. This reflects its ability to grow well in both wetland and terrestrial soil types, which is an important consideration for its use as a candidate species for paludiculture.

• 出版日期2017-8