Amino acids are the building blocks of protein and they are primary components in the machinery of cells, both in humans and in plants. In fact, just as plants require certain amino acids, humans require certain amino acids. And the best source of amino acids for humans is from plants.
For example, a healthy source of plant protein and amino acids is soybeans. It’s not an accident that the Latin name for soybeans is glycine max. Soybeans contain the highest level of the amino acid glycine found in plants.
Glycine is the smallest amino acid and because of its small size it penetrates plant tissues easily. This quality makes glycine an ideal chelating agent, which we will talk about in a minute.
As beneficial micro-organisms grow and multiply in a healthy, organic soil, they produce enzymes that break down and digest organic matter. One of these enzymes is called protease, which is an enzyme that breaks down large protein molecules into its constituent small amino acids that can be taken up by roots. This process of digesting protein is called enzymatic hydrolysis, and it preserves the biological structure, or chirality, of the amino acid molecules.
Amino acids produced by enzymatic hydrolysis have a left-handed orientation and are called l-amino acids. L-amino acids produced by micro-organisms are easily absorbed by plant cells. Synthetic amino acids produced by acid or alkaline hydrolysis have a right-handed orientation called d-amino acids that are not biologically active.
By adding l-amino acids derived from enzymatic hydrolysis directly to the reservoir, hydroponically grown plants will respond in the same way as plants grown in the best organic soils. One must be careful to ensure beneficial micro-organisms are already in place before the introduction of proteinaceous material to the nutrient solution because detrimental organisms also use protein and amino acids.
Chelates are molecules whose shells are formed around a metal or mineral. Often the metal or mineral by itself is easily tied up or reacted with other chemicals in the environment. By forming a shell around the mineral it can be taken up by the plant and not lost to the environment.
There are many chelating agents, both natural and synthetic, but amino acid-formed chelates offer something synthetic chelates do not. Amino acid chelates are completely used by plants—the shell and the mineral. Because glycine is the smallest amino acid it naturally makes the smallest chelated molecules that pass readily through plant tissues. Once inside the plant, the mineral or metal (e.g. calcium, zinc, manganese, magnesium, etc.) is released, and the leftover amino acids that formed the protective shell are either used by the plant directly as amino acids or further broken down into water-soluble nitrogen.
After all, amino acids are primary building blocks in cell machinery. Everything is used, nothing is lost. In fact, in wine making the vintner has to add minerals and nutrients for the yeast to live on. Yeast requires certain forms of nitrogen called YAN, or yeast assimilable nitrogen. Amino acid chelates are considered YAN.
Amino acid chelates also have a dramatic effect on calcium uptake by roots, especially chelates utilizing the amino acids glutamic acid and glycine. In soil and in hydroponics, calcium tends to react with phosphates and sulfates, precipitating out of solution as lime scale. Lime scale makes calcium unavailable to the plant.
Over time lime scale can clog up pumps, drip tapes and irrigation lines—a constant concern of hydroponic growers. Amino acid chelates are amino acid shells formed around the calcium ions like a claw, preventing calcium from reacting with other minerals in the water to form lime scale.
At the same time, glutamic acid and glycine amino acids stimulate root cells to open up calcium ion channels, allowing plants to take up calcium ions thousands to millions of times faster than simple osmosis.
The increased availability of calcium provided by amino acid chelated calcium has secondary benefits. For instance, a plant with a strong vascular system takes up water and nutrients more efficiently, increasing the Brix or sugar content of the plant.
Brix is a measurement of the percentage of sugar content in the sap and is a general indicator of the health and vigor of the plant. It is measured with a refractometer, not an EC meter. Organic molecules do not conduct electricity, but the total dissolved solids in water bend, or refract, light.
Using a Brix refractometer is easy. A few drops of sap are squeezed onto the glass slide of the refractometer, and the instrument is pointed toward a light source. The higher the dissolved solids in the sap, the more it refracts light and the higher the Brix reading. It has been reported that if the Brix of the sap exceeds 12%, sucking insects won’t even recognize the plant as food. Brix is also used as an objective measurement of the quality of fruit and vegetables.
Premium-quality produce has the highest Brix levels. Therefore, plants grown with amino acid-chelated supplements are generally richer in sugars and other nutritional elements, allowing them to be sold at premium prices. A high Brix content is especially important for wine grapes. The higher the Brix reading in wine grapes, the higher the potential alcohol content of the wine, and the sweeter the fruits and berries.
Amino acids also play a role in protecting plants against insects and disease. Weak plants have extra water between the cell walls, providing easy access to sucking insects and fungal pathogens. Strong plants with extra pectin between the cell walls are hardened against attacks, forming a physical barrier against invaders.
Calcium is also a secondary messenger. When plants are under attack from insects and other pathogens, calcium release starts a chain reaction that produces secondary metabolites to repel the attackers. Therefore, supplementing plants with amino acid-chelated calcium can help strengthen the plants’ natural immune system, potentially reducing the need for pesticides and fungicides.
The most interesting amino acid is tryptophan. This amino acid has an important function in both plants and humans. Tryptophan is a precursor molecule to the plant growth hormone indole acetic acid (IAA).
In humans tryptophan is a precursor to the brain neurotransmitter serotonin as well as the skin pigment melatonin, which is associated with sleep. It’s no wonder that turkey meat, which is high in tryptophan, makes us sleepy after a large Thanksgiving dinner.
Amino acids are critical for healthy plants and healthy people. Don’t underestimate amino acid fertilizers and chelated minerals for your indoor garden. Remember, healthy plants make healthy people and amino acids benefit both.