Ammonium/nitrate ratio in the initial growth of Guaco

Abstract

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 NO3ratios. 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 NO3ion positively favored the initial growth of Guaco.