Providing microelements and biostimulant effects by spraying aminocholates (Micromix Zenith, Germany)
Introduction
Microelements are essential for plant growth and development, and their deficiency disrupts plant growth and development. Unfortunately, a large part of Iranian soils do not have the ability to supply these elements to plants. Although some of these elements may be present in Iranian soils in sufficient quantities, the conditions for absorption are not there.
Alkaline pH, high levels of lime, salinity of water and soil, and high levels of phosphorus are among the most important reasons for these conditions.
Since the amount of plants’ need for these essential elements is very low, and on the other hand, the possibility of absorbing them from the soil is affected by limiting factors, foliar spraying of these elements and absorption through the leaves is an alternative and effective method for supplying microelements.
Chelation is a way to improve the absorption of micronutrients.
One of the problems of foliar spraying of microelements is their instability in water. This is because the water used in foliar spraying contains many compounds such as carbonates, bicarbonates, calcium and magnesium, etc., and these compounds react rapidly with iron, zinc, manganese, etc., and while stabilizing, they greatly reduce their effectiveness and absorption. Therefore, if we use sulfate compounds of these elements such as iron sulfate, zinc sulfate, manganese sulfate in foliar spraying, in practice, because these sulfates ionize in water and the ions of metal elements react rapidly with active non-metallic ions such as carbonates, bicarbonates and calcium, they cause a severe reduction in the absorption of these elements by plants.
An effective and practical solution is to chelate the desired mineral elements with organic compounds. Chelating means surrounding and involving the mineral element with organic compounds that make the mineral element’s access to other compounds impossible or minimizes it, and in this way the desired mineral element is preserved and slowly made available to the plant at the right time.
There are different types of chelating compounds, the most famous of which are EDTA and EDDHA.
Ethylene Diamine Tetra Acid or ethylene diamine tetraacetic acid with the chemical formula C10H16N2O8 is EDTA.
Its structure has:
2 amine groups -NH2
4 carboxyl groups -COOH
EDDHA or Ethylene Diamine-N,N’-bis(Di Hydroxyphenylacetic Acid) with the formula C18H20N2O6 The molecule ethylene diamine – N. N bis (dihydroxyphenylacetic acid) in addition to amino and carboxyl groups, has hydroxylated aromatic rings that provide very high binding strength to iron.
The important thing about EDDHA is that it has three isomers. The molecule of this chelate has two aromatic rings on which the hydroxyl group can be placed in different positions, which is why it has three main isomers. The figure below shows these three isomers best. Pay attention to the position of the hydroxyl group -OH and its connection to the aromatic ring.
The best chelating form is the ortho-ortho isomer, and the higher the amount of this isomer, the higher the quality of the iron chelate.
The other two isomers, ortho-para and para-para, have weak chelating power, and the higher their amount, the lower the quality of the iron chelate. Apart from these two important chelators, there are many other chelators, each with its own advantages and disadvantages.
One of the most important disadvantages of all these chelators is that after the mineral element is released, the remaining molecule, i.e. its organic part, is a useless and sometimes annoying molecule, and it has no practical use and practically does not play any role in the various mechanisms of plant physiology.
Amino acids as chelators of micronutrients and their effect on reducing plant stress
Amino acids are the building blocks of proteins and proteins are the foundation of life on Earth. Today, the direct use of amino acids in plant nutrition and their unique role in the growth and development process of plants is no secret to anyone.
In addition to their nutritional role, amino acids can act as chelators (Chelatin Agents) for micronutrients such as iron, Fe, Zn, manganese, Mn, copper, Cu, and to some extent calcium, Ca. This feature increases the absorption and transport of nutrients in the plant.
Amino acids are chelators that themselves play a very important role in plant nutrition.
Chelating Mechanism of Amino Acids
The amino acid molecule has two active groups:
Amino group (−NH2)
Carboxyl group (−COOH)
These groups are able to bond with metal ions and form stable complexes. For example:
Glycine + iron → iron _ glycine complex
Glycine + zinc → zinc _ glycine complex
These complexes are much more effective than free metal ions for the following reasons:
They are more stable.
They are less prone to precipitation.
They pass through the leaf cuticle more easily.
They move faster in the plant’s vessels.
Benefits of foliar application of microelements with amino acids
A: Increased foliar absorption
In foliar application, free iron or zinc ions (e.g., using iron and zinc sulfates) may precipitate on the leaf surface or have difficulty passing through the cuticle. However, when these mineral elements are in the form of amino chelates:
Penetration through the cuticle increases.
Entry into epidermal cells occurs more quickly.
Fertilizer use efficiency and effectiveness increase.
B: Reduced element fixation
The fixation and precipitation of metal elements in alkaline and hard water is reduced.
((The amino acids in amino chelates prevent the formation of insoluble hydroxides and keep metal elements in solution for a longer period of time, and as a result, the absorption and effectiveness of the compounds are increased.))
C: Better transport in the plant
Amino chelate complexes usually have greater mobility in the xylem and vascular tissues,
As a result, the desired microelement reaches the desired points faster and deficiency symptoms are eliminated sooner.
*** One of the most important points that distinguishes amino chelates from other chelates is that ultimately the amino acids in them themselves also play a role in physiological processes, and in this way, while providing microelements, the plant also benefits from the positive role of amino acids. ***
The role of amino acids in reducing and improving the negative effects of environmental and biological stresses
As mentioned, amino acids are not only carriers and protectors of microelements, but they also play an important role in stress metabolism (environmental and biological). This important role of amino acids in controlling and strengthening plants will be explained in detail.
Biostimulants and their place in plant nutrition
Biostimulants are a group of substances or microorganisms that do not act directly as fertilizers, but stimulate the physiological processes of the plant, and as a result, they increase the absorption of nutrients and the plant’s tolerance to stresses, and ultimately improve performance and increase plant production.
The definition accepted in Europe by the European Biostimulants Industry Council is:
Plant biostimulants are products that stimulate plant nutritional processes independently of their nutrient content and their aim is to improve nutrient utilization efficiency, tolerate abiotic stresses, increase crop quality and increase nutrient availability in the soil and rhizosphere.
As mentioned, fertilizers provide nutrients (micro and macro) to the plant, but biostimulants increase the plant’s ability to use available nutrients and their tolerance to stresses. According to the above definition, ferrous sulfate fertilizer, and amino acids or seaweed are considered biostimulants.
Modern agricultural technologies, along with extensive research conducted in plant nutrition, lead us to the conclusion that in order to maximize the use of fertilizers or, in other words, increase the efficiency of fertilizer use, we are forced to use more biostimulants.
In addition to increasing the efficiency of fertilizer use, biostimulants help plants to tolerate the various stresses they are exposed to.
The use of biostimulants alone, without the use of micro and macro fertilizers, is common and has yielded excellent results. However, if these compounds are used together with macro and micro elements, they will have a synergistic effect.
Reputable scientific articles and research in recent years on amino chelates and their effectiveness in greenhouse strawberries, pistachios, citrus fruits
By reviewing reputable articles published in the years 2023 to 2026, it can be said that the scientific view on amino chelates and fertilizers based on amino acids has changed from “simple nutritional sources” to “nutritional biostimulants”. Today, it is believed that their effect is not only due to the provision of nutrients, but also by improving the absorption of nutrients, regulating nitrogen metabolism, increasing antioxidant activity, and promoting stress tolerance, resulting in optimal growth and development and ultimately maximum production.
A study conducted in 2024 on greenhouse hydroponic strawberries showed that amino acid-based biostimulants increased vegetative growth and performance and significantly increased plant resistance to environmental stresses.
Another study in 2024 showed that the use of soluble fertilizers containing amino acids, even under conditions of a 30% reduction in nitrogen, increased nitrogen use efficiency, compensated for the decline in growth and fruit quality, and even improved fruit quality.
Another study on the use of potassium amino chelate in strawberries showed that under cold stress, the activity of antioxidant enzymes CAT, SOD, APX increased and oxidative damage was less than with conventional potassium sulfate.
A look at numerous articles on the use of amino chelates of iron, zinc, manganese, and potassium shows that stress caused by water salinity and cold stress is well controlled in strawberries under the influence of these nutritional biostimulants. Reduction in nitrogen consumption, tolerance of transplant stress, and tolerance of summer heat stress are other tangible and significant results of using amino chelates.
In pistachio orchards, many field studies have shown that foliar spraying of iron and zinc amino chelates causes:
Increase in chlorophyll concentration
Reduce leaf yellowing
Improve young shoot growth
Increase in kernel percentage
Increase in flower bud formation
The most important advantage in pistachios is increased iron and zinc absorption in alkaline and calcareous soil conditions.
In many experiments, amino chelates have had much greater absorption and efficiency than conventional sulfates.
In citrus, more focus has been on eliminating iron chlorosis and increasing tolerance to salt stress. The results show that the use of iron, zinc and manganese amino chelates increases chlorophyll, improves photosynthesis and leaf color, and reduces oxidative stress.
In a comprehensive study between Zenith Company and the University of Göttingen, Germany, on potted poplar seedlings, two of the company’s compounds were used: Calista (a mineral compound of marine limestone with a very high percentage of calcium and silicon) and Micromix (amino chelate with 25% amino acids). The results were obtained in the following table:
It should be noted that each treatment was sprayed once with a dose of 1 in 1000. The Callista-Micromix treatment was sprayed first with a dose of 1 in 1000 and then with a dose of 1 in 1000.
A look at the results shows that the Callista-Micromix treatment has a significant difference with the control in all parameters. This experiment shows the synergistic effect of amino chelate compounds (Micromix) and important elements such as calcium and silicon.
The important effects of amino chelates occur in four ways:
Chelating nutrients
Stimulant function
Stimulation of the antioxidant system
Regulation of the expression of genes related to stress
Micromix Zenith: Supply of microelements, biostimulant effects
This mixture is a mixture of micronutrients (Fe, Zn, Mn, Cu) that are chelated with amino acids. It is primarily considered an aminochelate micronutrient fertilizer, not a pure biostimulant
But why is Micromix Zenith considered more of a biostimulant mixture that also provides microelements to the plant?
The answer to this question is related to two important points in this extraordinary mixture that make the biostimulant aspect of this mixture very prominent, so that while providing micronutrients, its positive biostimulant effects are evident. The first point is its high level of amino acids, and the next important point is related to the type of amino acids selected in this mixture. 25 percent of its amino acids are mainly free and left-handed, and effective amino acids such as glycine, proline, and glutamic acid make Micromix Zenith special.
In this type of compound, two mechanisms operate simultaneously:
Nutritional role
A look at the percentage of microelements in this compound (weight-weight percentage) shows that the amount of microelements is at an appropriate level. On the other hand, these elements are chelated with amino acids.
When dissolved in the foliar spray tank, microelements are exposed to various compounds and ions, and there is a possibility of combining with them and removing them from the absorption process from the leaves. For example, if we use ferrous sulfate to provide iron as a foliar spray, the ferrous sulfate is ionized in the water and the iron ion exposed to the carbonate in the tanker water becomes insoluble iron carbonate and precipitates.
Fe++ + CO3−− → FeCO3
The chelation of these mineral elements such as iron and zinc with amino acids and the creation of amino chelates increases their stability in the spray tank until they are absorbed by the leaves. This increases the efficiency of foliar spray.
Another important and effective point in the nutrition of microelements chelated with amino acids is their absorption by the leaf. Amino acids do not just passively pass through the leaf cuticle, but an important part of their absorption and movement is carried out through specific carriers. (Amino Acid Transporters)
This is one of the main reasons for the higher efficiency of amino chelates compared to many mineral salts in foliar spraying.
After foliar spraying, in the first stage, amino acids are absorbed either through the cuticular route or through the stomatal route. In the next stage, specific carriers come into action and transport amino acids into the cell by spending energy. It is at this stage that microelements chelated with amino acids enter the cell.
When an element such as iron or zinc chelated with amino acids enters the plant, two situations may occur:
1 – The complex is broken down in the apoplast (the space outside the plasma membrane) and then the amino acid is absorbed through its own specific transporters and the metal element through its own specific transporters.
2 – The small amino chelate complex is directly absorbed and then broken down inside the cell and then enters the vascular transport system.
Several transporters, including proT1, AAP2 and AAP1, are activated in the transport of amino acids to meristems, young leaves, fruits and seeds after being transferred to the vascular system.
Therefore, it can be said with certainty that foliar-applied amino acids are not absorbed only through passive diffusion, but are actively absorbed by specific membrane transporters after passing through the cuticle and then transported into the vessels.
As mentioned, amino chelates have a more effective nutritional role than synthetic chemical chelates, both in preserving and maintaining the desired microelement and in absorbing and transporting them in plant organs.
Biostimulant role
25% of amino acids in this compound is a very high amount. This is while most amino chelates available in the Iranian agricultural market have between 5 and 15% amino acids.
This high amount of amino acids causes us to witness the positive effects of amino acids in addition to chelating. In other words, we can say that Micro Mix Zenith is more of a biostimulant compound.
More than 95% of the amino acids in this compound are free and all are left-handed.
Arginine, Glycine, Glutamic Acid, Serine and Proline are the highest percentages of amino acids in this compound.
Amino acids do not only play the role of chelating and transporting elements, although glycine performs this role especially well.
The amino acids in the composition of Micro Mix Zenith are presented according to the aminogram, and while they are of plant origin, they are engineered and selected with modern technology, and this aminogram is not accidental and is the result of experience, knowledge and technology. The set of amino acids has been selected in such a way that, in addition to maximum chelating (high levels of glycine), they also have the greatest biostimulant effect (high levels of proline, glutamic acid and arginine), which play an important role in stress metabolism.
The role of amino acids in reducing and improving the negative effects of environmental and biological stresses
Amino chelates are not only important in terms of providing plant microelements due to the amino acids they contain, but also the effect of their accompanying amino acids is very important under the name of what we call biostimulant effects.
This is well demonstrated in the foliar application of Zenith Micromix, which has a high percentage of amino acids (25 percent).
The amino acids in this fertilizer-biostimulant combination are not only carriers and protectors of micronutrient minerals, but they also play an important role in the stress process (environmental and biological). This important role of amino acids in controlling and strengthening the plant against various stresses will be explained in detail below.
In drought and water deficit stress, the plant experiences a decrease in turgor pressure and an increase in free radicals. In such conditions, when the plant is under stress, amino acids, especially proline and glutamic acid, reduce the negative effects of drought stress by maintaining the osmotic balance of the cell and conserving water in various plant tissues, as well as by protecting cell membranes.
In salinity stress, water absorption decreases and sodium toxicity increases. Since the conditions are similar to drought stress, amino acids, especially proline and glutamic acid, along with glycine and arginine, help plants overcome salinity stress by regulating the osmotic pressure of the cell and thereby preserving its water, as well as by protecting proteins and membranes and neutralizing free radicals. The presence of amino acids such as proline, glutamic acid and arginine plays the greatest role in plant tolerance to salinity stress.
In oxidative stress, amino acids are very effective and play an important role in controlling ROS (Reactive Oxygen Species). And in fact, amino acids do this by activating antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT).
Oxidative stress is one of the important factors in the negative effects of various stresses, especially in thermal stress. Balancing the physiological conditions of the plant during stress and even after the stress is over is one of the very important roles of amino acids.
In thermal stress, extreme heat causes the plant to suffer problems such as protein denaturation and increased ROS. In addition to proline, methionine also plays a very important role, and cysteine also reduces the damage caused by thermal stress by reducing oxidative damage and chloroplast stability. When plants are affected by extreme heat or cold, the structure of proteins, especially in chloroplasts and mitochondria of cells, is damaged and destroyed.
In extreme cold, where we are faced with cell destruction, if amino acids such as proline, methionine, glutamic acid and arginine are increased in the cytoplasm and plant sap before the onset of cold (spraying solution before freezing), they are effective in reducing the damage caused by cold stress. On the other hand, after the damage caused by cold stress, it is possible to accelerate the recovery and regeneration of aerial organs by spraying a mixture such as Micromix Zenith and increasing amino acids.
Many amino acids themselves are signaling molecules. Glutamate activates receptors, which as a result regulate nitrogen absorption, root growth and stress response. Proline, in addition to its unique roles, also acts as a messenger molecule in salinity and drought stress.
In biological stresses, amino acids also help maintain and improve photosynthesis in stresses, which means that production in the plant continues, which improves and helps the repair process and increases production.
When plants are exposed to a pest or disease, this biological stress affects growth and development and, of course, production. The use of pesticides, while helping farmers to get through this stage, puts the plant under metabolic stress again. If at this time, various amino acids such as proline, glycine, glutamic acid, arginine and methionine are available to the plant, protein synthesis is accelerated and increased, as a result, photosynthesis is also improved and increased, and ultimately plant tissues are quickly repaired and regenerated, and the plant’s recovery period is shortened.
New research shows that glycine and glutamic acid are the most effective amino acids in increasing foliar absorption of iron, zinc, and manganese, while proline plays the most anti-stress role and regulates the response to salinity and drought. This is very important in the formulation and final aminogram of advanced amino chelate compounds. This is evident in the aminogram of the Zenith Micro Mix compound.
Conclusion:
Today, with the advancement of knowledge and technology, it is not only important to provide nutrients, but also to use special compounds, which are called biostimulants, along with nutrients, which greatly increase their nutritional effect.
Biostimulants are products that stimulate plant nutritional processes independently of their nutrient content, and their goal is to improve the efficiency of nutrient consumption, increase tolerance to environmental stresses, and also increase the availability of nutrients in the soil and rhizosphere.
Amino acids, humic, fulvic and chitosan are some of these important and wonderful compounds.
The very important and effective product Micromix Zenith has been designed and produced with Zenith Company’s latest technology and knowledge in view of this issue. The presence of more than 25% of free and selected amino acids such as proline and glycine has made this fertilizer mixture for foliar spraying not just a fertilizer for providing microelements, but has many positive side effects.
Authors: Arash Nikokar, B.A. in Agricultural Engineering and CEO of Nikokar Trading, Seyed Farid Sayah, M.A. in Plant Nutrition and Director of Research and Development at Nikokar Trading
References:
Chelated amino acids: biomass sources, preparation, properties, and biological activities Rania H. Jacob1 · Adel S. Afify1 · Sanaa M. Shanab2 · Emad A. Shalaby.
Amino acid-based biostimulants and microbial biostimulants promote the growth, yield and resilience of strawberries in soilless glasshouse cultivation Ruvini Ranasingha, Anya Perera, Kambiz Baghalian, Christos Gerofotis First published: 15 July 2024
Response of strawberry (Fragaria ananassa L.) to chilling and potassium supply from inorganic and amino acid-complexed sources Author links open overlay panelIman Salimi a, Amir Hossein Khoshgoftarmanesh b, Shakeh Markarian b, Seyed Ali Mohammad Mirmohammadi Maibodi c
Review of Amino Acid Foliar Application as a Stress Mitigation Strategy: Unraveling the Protective Mechanisms Against Abiotic Stress Xiaoyu Ma, Mirezhatijiang Kayoumu, Yue Yin, Zewen Wang, Guilan Duan First published: 10 February 2026
Effect of foliar application of amino acids on growth, yield and nutrient uptake of pistachio Vali Asr University of Rafsanjan Rastegari Ali Akbar Saedi Gholamreza
Effect of amino acids Amine and micronutrients on grape yield and quality Shiraz University Ronaghi Mohammad Reza
