Fertilizing with Amino Acids
In the laboratory, foliar or root fertilization based on amino acids shows a triple effect on plants : nutritional, biostimulant, and abiotic anti-stress. It helps crops resist harsh conditions such as cold, pests, drought, oxidative stress and allows better assimilation of traditional fertilizers.
Description
Amino acids, as well as proteins and other derivatives they form, are involved in all biological processes of living organisms, both plants and animals. In plants, different amino acids are present in varying proportions and fulfill different roles. There are hundreds of amino acids, but only 22 are called essential amino acids because they form proteins.
They are all important and a deficiency can have significant consequences. In plant production, treatments based on amino acids must therefore be designed according to the plant's needs : growth phase, stress situation due to frost or drought,...
Commercially available products are often composed of amino acids of animal origin or obtained by chemical synthesis. They are then less assimilable by the plant and can, in some cases, cause phytotoxicity.
Amino acids, basic constituents of plants
The chemical and biological properties of a protein depend on the number and type of amino acids it contains and the order in which they are arranged in the molecule. Amino acids or their derivatives are involved in all biological processes.
Not all plant amino acids have the same importance in the biological cycles of plants and are present in different proportions.
For example :
- Lysine, methionine, and tryptophan are needed in low concentrations while glutamate and aspartate, through transamination giving rise to all other amino acids, are present in large quantities in plants.
- Proline acts on water management for crops, strengthens cell walls and plants are therefore more resistant to unfavorable climatic conditions.
- Glycine is crucial in the formation of plant tissues and is one of the first compounds used in chlorophyll synthesis and is thus a means of preventing chlorosis.
- Lysine and arginine are active in stimulating photosynthesis and delay the senescence process.
All amino acids are important and interdependent, and the deficiency or absence of one can block the synthesis of others.
Period of use
The amino acid content varies according to the physiological state of the plant. Concentrations are higher during dormancy periods when protein synthesis decreases (accumulation of amino acids). During growth periods, these reserves are used for protein synthesis, and consequently their concentration decreases.
Therefore, the best time for treatments is when the plant has a specific and significant need for amino acids : growth, development, and fruit formation phases, or when frost, drought or any other abiotic stress has altered the plant's synthesis capacity.
Two sources of amino acids
There are plant and animal origin amino acids.
The effectiveness of a fertilizer with amino acids is not only due to the total concentration of amino acids and their aggregation state, but also the balance of proportions in which each acid amino acid is present.
Plant origin amino acids
Through their origin and production process by enzymatic hydrolysis, they provide amino acids in a form and balance more appropriate for plants, for maximum efficiency and optimal quality of action. By analyzing the amino acids contained in plants, it can be seen that they are all optically active and levorotatory, unlike those produced by chemical synthesis or by alkaline or acid hydrolysis. Plant amino acids therefore retain their full biological functionality.
Only levorotatory amino acids can be assimilated and used in the biological cycles of plants. Dextrorotatory amino acids are not recognized by enzymatic function and are not used in protein synthesis in the best cases, otherwise, in the worst cases, they can create phytotoxicity situations.
Thanks to the exclusively plant origin (no use of animal waste or waste from tanneries, etc.) and their manufacturing process, plant amino acids do not contain residues of antibiotics (fermentation residues), trace metal elements (chromium, lead, mercury...), chlorides or any other contaminants.
Animal origin amino acids
They contain hydroxyproline and hydroxylysine, 2 amino acids not metabolized by plants and therefore not useful for them. Conversely, the contents of aspartate and glutamate are higher for plant origin, as they directly contribute to plant development.
They come from animal by-products, such as waste from tanneries, leather, or rendering plants. Some fragile amino acids are destroyed by the manufacturing process for animal origins (tryptophan, cysteine, lysine, etc.). Glycine, mainly present in collagen, has a stimulating effect at low concentration and is phytotoxic above a certain dosage.
Finally, animal hydrolysates mainly stimulate the rhizosphere, while plant hydrolysates directly stimulate the plant.
Advantages
Fertilizers based on plant amino acids are rapidly absorbed and incorporated into the plant. Thanks to their ability to penetrate cell membranes and integrate into metabolic processes, they can fulfill their function in plants within a few hours.
The supply of plant amino acids is therefore essential when the plant is subjected to stress conditions for amino acid synthesis. This application allows considerable energy savings, enabling rebalancing and restoring optimal conditions for plant development.
The main effects are triple : nutritional (5% nitrogen), phytostimulant and/or abiotic anti-stress.
The consequences of applications on crops are numerous, depending on the stage of application :
- Increase in yield and quality.
- Better pollination and fruit set.
- Improved organoleptic quality of fruits and vegetables.
- Slowing down of senescence.
- Optimized nitrogen absorption (even for mineral forms).
With the direct supply of amino acids, the plant will save a higher energy expenditure, since it will not need to perform the biochemical transformations of inorganic nitrogen into amino acids.
Amino acid applications
Foliar
In foliar application, fertilization acts as a vegetative development activator by providing the amino acids and peptides most needed by the plant.
Nettle has a nutritional and intrinsic resistance signature thanks to the amino acids it contains which will serve as a basis for protein synthesis[1].
Combinations with other products such as phytosanitary products or foliar fertilizers are generally possible, except for those containing sulfur and other alkaline products (pH>8).
Root
In application as watering, fertilization provides the soil with nutrients directly absorbable by the plant, improving soil microbial activity, humification, mineralization, and chelating activity.
Seed coating
The principle is simple : the plant needs access to light to perform photosynthesis and produce reducing sugars, from which, with nitrogen, they form amino acids involved in the metabolism (protein constitution, vitamin synthesis, etc.) of germination and root system growth.
By coating with amino acids, the cultivated plant no longer needs access to light, it immediately has access to the coating elements, allowing a much better growth dynamic than weeds. Coating increases the root exploration surface at the beginning of the cycle. Moreover, microorganisms can be added which will be directly functional at sowing, implying better control of the initial symbiosis.
For example, Trichoderma, a very competitive neutral fungus, develops in the plant's root system and occupies the space throughout the campaign like a shield to block pathogenic fungi.
Sources
- Amino acids, the building blocks of all cells? - Biobase.
- Amino acids, the building blocks of all cells? - Arbo Bio infos.
- Amino acids -L levorotatory – High assimilation – Usable in Organic Farming - Auxine.
- Worm earth : Mathias and natural applications - Marne Chamber of Agriculture.
