The Effects of Amino Acids, Phenols and Protein Hydrolysates as Biostimulants on Sustainable Crop Production and Alleviated Stress

Abstract

Abstract: Biostimulants which contain substances or products, including natural compounds, special formulations and microorganisms have gained considerable attention as sustainable methods for heavy metal detoxification, stimulating natural toxins, controlling diseases and pests, and increasing both water and nutrient efficiency. Biostimulants are important products in modern agriculture, which are composed of different heterogeneous classes of compounds with a broad spectrum of action to increase both qualitative and quantitative productions. Amino acids can be useful in stress defense, photosynthesis, for increasing nutrient uptake, pollination and fruit formation, and as precursors to hormones and growth parameters. Amino acids are considered as precursors and constituents of proteins, which are well-known for the stimulation of cell growth. Because they are the basic building blocks of proteins, amino acids are very important in plant growth, development and metabolite synthesis. One of the diverse, notable and large group of secondary metabolites is phenolic compounds, which have important function in regulation of the plants’ physiological activities, oxidation-reduction processes, and photosynthesis. Protein hydrolysates contain amino acids and peptides, one of the most important kinds of biostimulants. Protein hydrolysates have a notable capability to increase crop performance, particularly under environmental stress conditions. This review article is aimed to introduce and find more about the roles of different types of biostimulants in plant growth and final yield production, leading to sustainable agriculture.