| The southern Brazilian highland plateau is a mosaic of two contrasting plant communities, Araucaria forests and grasslands, which differ in the relative abundances and spatial patterns of soil nitrate and ammonium. However, we still do not know the inorganic N preferences of one key species in this mosaic, Araucaria angustifolia, the dominant tree species in the Araucaria forests and an important tree species invading the adjacent grasslands. Growth responses measured in a greenhouse study demonstrated that the species prefers NH4+ over NO3- as an inorganic N source. When provided alone, NO3- induced N deficiency symptoms: increases in root: shoot ratio, root branching and leaf mass per area, thickening of the shoot apexes and decreased mass-based... |
