Abstract
Biomass, leaf area, canopy photosynthesis, photosynthetic nitrogen-use efficiency (PNUE), nitrogen-partitioning ratio (NPR: ratio of nitrogen taken up by jack pine relative to two different competitor species), and nitrogen uptake (NU) of jack pine ( Pinus banksiana Lamb.) competing with large-leaved aster ( Aster macrophyllus L.) and Canada blue-joint grass ( Calamagrostis canadensis (Michx.) Beauv.) were examined at three nitrogen levels in a controlled-environment growth chamber. When grown with large-leaved aster, jack pine biomass, photosynthesis and PNUE ( p<0.001) increased as nitrogen level increased. Jack pine biomass, photosynthesis and NPR ( p<0.001) decreased as nitrogen level increased when grown with Canada blue-joint grass. At the lowest nitrogen supply level, jack pine photosynthesis decreased as competitor PNUE increased ( r 2=0.84, p<0.001). Jack pine photosynthesis decreased as NU of large-leaved aster (37.5 mg N l −1: r 2=0.75, p<0.001; 100 mg N l −1: r 2=0.86, p<0.001) and Canada blue-joint grass (37.5 mg N l −1: r 2=0.96, p<0.001; 100 mg N l −1: r 2=0.84, p<0.001) increased. NU and PNUE may play an important role in the outcome of interactions between jack pine seedlings and competing forest vegetation in newly planted stands.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call