Amino acids, the building blocks of proteins, continue to get a lot of attention in agriculture. Proteins are one of the major components of the structure and the chemistry of living things. Amino acids may be linked together to form more than 50,000 different proteins. The primary function of amino acids is to furnish the essential material for duplication of genetic code, for cell division, and for forming tissue. Amino acids are also involved in the metabolism of hormones and enzyme systems. A healthy plant is continually breaking down proteins into individual amino acids, and then re-assembling those into new proteins as needed.
The question of whether the supplementation of amino acids can positively impact a plant is not at issue. Amino acids are highly effective as chelators, which allow the solubilization and the transfer of relatively insoluble materials into plants. But it’s important to combine amino acids with other materials to help the plant have the right proteins to work with. Our fish hydrolysate Pacific Gro and soil and foliar fertilizers from Ecotech both have amino acids as part of their complex structures.
There remains some disagreement on whether amino acids can be effective when applied as a foliar spray. Can a plant absorb the entire amino acid molecule? There is research showing that foliar applications of proline, an amino acid that is used in the biosynthesis of proteins, has improved the growth and development of various crops against salt stresses. There is additional research suggesting that systemic amino acids influence the biochemical defense pathways and suppression of root rot nematodes.
I think it’s more a question of how much of the amino acids get absorbed by the plant versus whether a plant can process amino acids. Foliar-applied water-soluble amino acids can be absorbed by plants through stomata and can participate in various cellular processes, including signaling. Even at very low concentrations, their effect is quite substantial. Application of amino acids as foliar spray can alter crop performance by either signaling or by being a nitrogen source. Because amino acids are also an N source and can be metabolized, it’s unclear whether their effect on NO3- uptake results from a role as signaling molecules or from their role in overall nitrogen supply.
We have two types of benefits from amino acid foliar application. One, as just mentioned, the nutritional aspects of N and, two, chelation or nutrient mobilization, enhancement of certain metabolic pathways, disease suppression, etc. I’m sure there will be more innovative research regarding amino acids and I look forward to learning more, but for today, amino acids remain a solid contributor as a biostimulant in agriculture.