Amino acids play a crucial role in plants, just as they do in animals. Here are some of the main functions of amino acids in plants:

• Protein constituents : Amino acids are the basic units that make up proteins. Plants use these proteins for numerous biological functions, such as cell structure, enzyme catalysis, nutrient transport and metabolic regulation.

• Photosynthesis : Certain amino acids, such as glycine and serine, are directly involved in the process of photosynthesis. Photosynthesis is the process by which plants convert sunlight into usable chemical energy.

• Nutrient transport : Certain amino acids are involved in transporting nutrients throughout the plant. For example, amino acids known as "branched side chain amino acids" are often used to transport ions and other molecules within the plant.

• Stress response : Plants use certain amino acids to respond to stress conditions, such as non-protein amino acids (proline, glycine betaine), which can help protect cells against damage caused by environmental stress.

• Synthesis of bioactive compounds : Certain amino acids serve as precursors for the synthesis of bioactive compounds in plants. For example, tryptophan is a precursor of auxin, a plant hormone that regulates plant growth.

• Defense against pathogens : Certain amino acids are involved in plant defense mechanisms against pathogens. They can act as chemical signals to activate immune responses.

Amino acids in biostimulants are often preferred in their levorotatory (or L) form, meaning that they have a specific molecular configuration. This is mainly because living organisms, including plants, generally use levorotatory amino acids for protein synthesis.

Amino acids exist in two mirror forms, levorotatory (L) and dextrorotatory (D), which are mirror images of each other. Proteins in living organisms are composed of levorotatory amino acids. Enzymes, which are proteins that catalyze chemical reactions in cells, are specific to the levorotatory configuration of amino acids.

When it comes to applying biostimulants containing amino acids in agriculture, levogyric amino acids are often preferred for several reasons:

• Biological compatibility : Levorotatory amino acids are more biologically compatible with plant metabolic processes. They are better recognized and utilized by the enzymatic systems involved in protein synthesis and other cellular processes.
• Efficiency in protein synthesis : Ribosomes, the cellular structures responsible for protein synthesis, are specifically adapted to use levorotatory amino acids. The use of D-amino acids in protein synthesis can lead to problems with protein structure and activity.
• Optimal biological response : Plants have evolved to use levorotatory amino acids, and the use of these forms in biostimulants aims to maximize biological response and plant benefits.

It should be noted that some biostimulants may contain mixtures of levorotatory and dextrorotatory amino acids, but the predominance of the levorotatory form is generally sought to optimize product efficacy.