Effect of Ammonium Fertilization on Acclimation of Ingá to High and Moderate Irradiance

ABSTRACT Nitrogen can be decisive for the tolerance of plants to stress factors such as high irradiance. This work aimed to investigate the effect of ammonium fertilization during acclimation of young ingá plants under two light environments. Accumulation and partitioning of dry matter, growth, photosynthetic capacity and leaf nitrogen content were analyzed in ingá plants subjected to moderate and high irradiance of 554.4±81 µmol photons m-2 s-1 and 1941±12.3 µmol photons m-2 s-1, respectively. The highest values of dry matter, growth and photosynthesis were observed in plants subjected to moderate and high irradiance fertilized with ammonium. The specific leaf area was higher in plants under moderate irradiance, while the treatments control and N fertilization showed no differences, independent of light condition. The ammonium fertilization contributed to acclimation and dry matter accumulation of ingá under moderate and high irradiance, while plants subjected to moderate irradiance invested in strategies for energy interception (e.g. specific leaf area).