Amino acids are the fundamental building blocks of proteins in living organisms, and their role in plants goes far beyond that; they are involved in growth processes, enzyme formation, photosynthesis, and plant responses to environmental stress factors. These shared functions among amino acids represent one of the most important areas of modern agricultural research, especially in light of the climatic challenges facing agriculture.

How Plants Absorb Amino Acids and Their Forms

• Plants benefit from amino acids not only as a nitrogen source but also as ready-made compounds that help them save the energy required to convert nitrate or ammonia into organic forms.

• Some amino acids, such as glutamine and asparagine, act as nitrogen carriers within the plant and serve as temporary storage forms in specific tissues.

• There are also various functional types of amino acids, such as threonine, serine, arginine, and GABA, which are used in growth regulation, tissue formation, and cell repair under damage or environmental stress conditions.

Physiological Functions of Amino Acids in Plants

1. Protein and Enzyme Formation:
   Every protein in a plant is composed of chains of amino acids; their presence in sufficient quantities determines the plant’s ability to build its organs and enzymes.

2. Supporting Root and Stem Growth and Seed Formation:
   Amino acids such as tryptophan are precursors of the plant hormone auxin, which stimulates the growth of lateral roots.

3. Enhancing Photosynthesis and Chlorophyll Production:
   Amino acids support the creation of proteins that are part of the light-absorbing components and assist in electron transport within chloroplasts.

4. Environmental Stress Resistance:

   • Amino acids such as proline accumulate under drought or salinity conditions and help maintain water balance within cells and the integrity of cell membranes.

   • Additionally, some amino acids act as antioxidants or stimulate the production of antioxidant compounds within the plant to reduce the damage caused by reactive oxygen species (ROS).

5. Signaling Molecules That Alert the Plant to Nutritional and Environmental Conditions:
   Some amino acids function as signaling molecules that interact with hormonal pathways such as auxins, abscisic acid, and others to regulate growth or respond to adverse conditions.

Green Practices to Enhance Plant Utilization of Amino Acids

• Use of bio-based products containing free amino acids or mixtures of amino acids and peptides to nourish plants, especially during sensitive growth stages such as seedling, flowering, and fruit formation.

• Incorporating amino acids as part of organic fertilization or biostimulants to enhance metabolism and improve the uptake of other nutrients.

• Providing optimal conditions of water, shade, and temperature, as environmental stresses increase the plant’s demand for amino acids for protection and cell repair.

• Using stress-tolerant plant varieties that respond effectively to amino acid supplementation to achieve higher and better-quality yields.

Conclusion

Amino acids are not merely the building blocks of proteins; they are functional molecules that regulate growth, enable plants to adapt to environmental changes, and maintain crop quality.
Applying modern knowledge in this field can transform agricultural practices toward higher efficiency and quality, particularly under current climatic challenges.

References

1. Heidarzadeh, A. Role of amino acids in plant growth, development, and stress responses: a comprehensive review. Discover Plants, 2025;2:237. DOI:10.1007/s44372-025-00322-0 SpringerLink

2. Wang, Q., et al. Roles of Functional Amino Acids in Plant Growth and Development. Plant and Cell Physiology, 2023. OUP Academic

3. Shen, S., Pan, L., Li, J., et al. The Involvement of Amino Acid Metabolism in the Mechanisms of Salt Tolerance Adaptation in Medicago sativa and Medicago truncatula. Plants, 2025;14(6):929. DOI:10.3390/plants14060929 MDPI