Changes in Root Architecture After Amino Acid Application in a Soybean Crop

Improving the root system favors better plant growth, since it promotes water and nutrient absorption, resulting in higher plant yield. In this respect, the use of products for this purpose has become promising. Applying amino acids has benefitted the root system of Arabidopsis and in some vegetables; however, little is known about their influence on soybean plants. As such, the aim of this study was to assess the effect of applying amino acids to seeds and leaves on the root architecture of soybean plants. Effects of amino acids such as glutamate, cysteine, glycine and phenylalanine on the main root length (MRL), total root length (TRL), projected area (PA), root volume (RV), number of secondary roots (NSR), secondary root length (SRL) and number of tertiary roots (NTR) were evaluated. All the amino acids studied improved root architecture. Seed-applied cysteine increased TRL by 55%, in relation to control. When applied on leaves, it raised TRL by 27% and MRL by 69%, compared to control. Applying glycine to seeds increased MRL by 54%, PA by 69%, RV by 96% and NTR by 119%, all in relation to control. Thus, amino acids enhanced the architecture of soybean roots. However, glutamate, glycine and phenylalanine produced better responses when applied to seeds, and cysteine, when applied to leaves. All of these changes may help roots absorb more water and nutrients, thereby raising crop yield.