The addition of amino acids to hydroponic nutrient solution often has a dramatic affect on plant growth. Again, the secrets of amino acids lie in nature. As beneficial microorganisms grow and multiply in a healthy, organic soil, they produce enzymes that break down organic matter. One of these enzymes is called “protease”, an enzyme that breaks down large protein molecules into small amino acids that can be taken up by the roots. This process 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 microorganisms are easily absorbed by plant cells, but synthetic amino acids produced by acid or alkaline hydrolysis have a “right-handed” orientation and 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.
Amino acids have a dramatic affect on calcium uptake by the roots; especially amino acid blends rich in the primary chelators- glutamic acid and glycine. In nature, as 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 also form calcium deposits that clog up pumps and irrigation lines, a constant concern of hydroponic growers. Amino acid chelators, on the other hand, attach to calcium ions like a claw, preventing them from reacting with other minerals to form lime scale. At the same time, glutamic acid and glycine stimulate root cells to open up calcium ion channels, allowing plants to take up calcium ions thousands to millions of time faster than simple osmosis!
Calcium is an immobile element. In other words, once it is deposited in plant cells it cannot be moved to other parts of the plant. Therefore, a constant supply of calcium must be available to the roots of vigorously growing plants. Calcium is very important for building strong cell walls. Calcium ions are transported from the roots to the new growth, where they react with pectic acid to form calcium pectate, also know as pectin. Pectin is the “glue” that holds cell walls together. When an abundant supply of calcium is available, cell division and cell wall expansion are accelerated. Calcium also activates the enzymes that pump auxins to the growing root tips and meristems. So calcium not only provides the raw materials to form new cell walls, it has an active role in instructing the plants to keep on growing!
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. On the other hand, 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 acids can help strengthen the plants’ natural immune system, often reducing the need for pesticides and fungicides. Other physiological diseases, such as tip burn in lettuce and blossom end rot in tomatoes are the direct result of calcium deficiency. So calcium/amino-acid chelates can help prevent calcium deficiency, reducing crop losses under high humidity and other calcium-limiting conditions.
Amino acids also help protect the plants from temperature stress. Plants with weakened cell walls are more susceptible to extremes of heat and cold. For example, during frost conditions the water between the cell walls crystallizes, puncturing the cell membranes and wilting the plant. But when the plant has extra calcium pectate between the cell walls instead of water, injury to the plant is minimized. For example, it is not uncommon for lettuce plants treated with amino acids to survive two or three hard frosts! Although most hydroponic vegetables are grown in a controlled environment, future research with amino acid supplements may suggest ways of growing plants at lower temperatures, without sacrificing quality or yield. As energy costs continue to escalate, the ability to condition plants against temperature extremes may have important economic benefits to growers.
The increased availability of calcium provided by amino acids has secondary benefits, as well. A plant with a strong vascular system takes up water and nutrients more efficiently, increasing the brix 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. Brix is measured with a refractometer, not with 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! Furthermore, for every 1% increase in brix, the freezing temperature is lowered by half a degree. 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 supplements are generally richer in sugars and other nutritional elements, allowing them to be sold at premium prices.