Ammonium/nitrate ratio in the initial growth of Guaco
Guaco is a plant that has secondary metabolites with therapeutic properties of interest in human medicine, mainly due to its action in respiratory tract diseases. Nitrogen is a nutrient that participates in the formation of several compounds considered to be of great importance for plant growth. Its main forms of absorption by plants are ammonium (NH4+) and nitrate (NO3-) ions and unbalanced ratios can change plant growth. This study evaluates the effect of NH4+ and NO3- (100:0; 75:25; 50:50; 25:75, and 0:100) ratios in nutrient solution on the initial growth of Guaco plants. Guaco growth was affected by NH4+ and NO3- ratios. When NH4+ was supplied as the exclusive N source, Guaco plants reduced dry biomass production, number of leaves, leaf area, specific leaf area, leaf area ratio, total chlorophyll, and chlorophyll a and b indexes. Thus, increasing doses of the NO3- ion positively favored the initial growth of Guaco.