Amino acids, peptides and proteins, as core organic compounds in biology, play an essential role in living systems-part1
In the growth and development cycle of crops, the intake and proportion of various nutrients and substances and their balance within the plant are crucial to the nutritional and physiological activities of crops, which directly affects the formation of the quality of crop fruits.
Amino acids: play a key role in this process, providing plants with essential amino acids can stimulate and regulate the rapid growth process of plants, enhance the robustness of plants and improve the efficiency of nutrient absorption. Amino acids can also accelerate the accumulation of dry matter in the plant and optimize the rate and total amount of nutrients transported from roots or leaves to other tissues, thus effectively adjusting the ratio and dynamic balance of macroelements, trace elements and other nutrients, and vigorously maintaining the normal growth and development of plants.
Peptide: A compound called a peptide is created when amino acids are linked by peptide bonds. Peptide chains can range in length from dipeptides containing only two amino acid residues to polypeptides containing approximately 50 amino acid residues. Specifically, those consisting of two amino acids are defined as monopeptides, those consisting of 2-10 amino acids are referred to as small molecule peptides or oligopeptides, and those polymerized over 50 amino acid residues are classified as proteins. It is important to note that many peptides possess biological activity, such as hormones and neuropeptides.
Protein: As a macromolecular complex consisting of a large number of amino acids linked by peptide bonds, it usually contains more than 50 amino acid residues and may consist of one or more interwoven polypeptide chains. Their three-dimensional structures are highly complex and contain a variety of important biological activities and functions, such as the catalysis of enzymatic reactions, structural support roles, and immune defense mechanisms. The unique function and activity of each protein not only depend on the type and number of amino acids and the sequence arrangement, but are also closely related to its specific spatial configuration.
Multiple functions and applications of free amino acids
The functions of amino acids in plant physiology and their applications are of great importance. Amino acids are not only the basic building blocks of proteins, but also can be directly absorbed and utilized by plants without conversion, and their uptake rate even exceeds that of nitrate nitrogen, and once applied to the soil they are rapidly taken up by the root system, making them a highly efficient and direct-acting fertilizer.
Essential amino acids for plants include, but are not limited to, alanine, arginine, aspartic acid, cysteine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine (methionine), phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine.
Depending on the R group, amino acids can be categorized into four main groups: non-polar amino acids (e.g., alanine, leucine, isoleucine, etc.), polar amino acids (e.g., serine, threonine, tyrosine, etc.), basic amino acids (e.g., lysine, arginine, histidine), and acidic amino acids (e.g., glutamate, aspartic acid).
Individual amino acids have unique roles in plant growth and development and in response to environmental stress:
Aspartic acid
1)Exhibits multifunctionality throughout the plant’s life cycle and is involved in a variety of physiological processes.
2)Promotes growth and development and exerts a stimulatory effect.
3)Enhances seed germination, promotes protein synthesis, and supplies essential nitrogen under adverse conditions.
Glutamate
1)Reduces nitrate accumulation in the crop, enhances seed germination, promotes leaf photosynthesis efficiency and chlorophyll biosynthesis.
2)Positively affects the subsequent flowering and fruiting stages.
3)Enhances the absorption and utilization of other amino acids.
Alanine
1)Associated with photosynthesis and chlorophyll acquisition, increases chlorophyll synthesis, makes plants greener and regulates stomatal opening and closing, intensifying plant metabolic activity.
2)Possesses some antipathogenic microbial effects.
Arginine
1)It is a natural growth hormone auxin precursor, involved in polyamine synthesis and enhances plant resistance to salt stress.
2)Stimulates the development of leaves, stalks and new shoots.
3)Particularly beneficial to root growth (methionine has a similar effect), often recommended as a stimulant for foliar sprays and fertilizer-water integration to promote nutrient uptake and root development.
Asparagine
1)Enhances nitrogen uptake.
2)Used to compensate for chlorophyll loss due to nitrogen deficiency and as a stimulant for foliar sprays.
Phenylalanine
1)Promotes lignin and anthocyanin synthesis as their precursors.
2)Plays an important role in protein synthesis and synthesis of phenolic compounds or oils, and is significant for the medicinal value of plant extracts as well as for the activation of plant self-defense systems.
Glycine
1)With a strong chelating capacity, high levels of glycine help plants to better absorb nutrients, either by soil application to form complexes or by adding it to irrigation solutions (make sure the pH is compatible with glycine).
2)Glycine also plays an active role in flowering and fertilization, and is particularly suitable for pre-flowering.
3)Closely related to chlorophyll and photosynthesis, it promotes sugar accumulation, which in turn stimulates new growth and budding.
Hydroxyproline
Closely related to flowering, pollination and fruiting processes.
Histidine
1)Maintains plant metabolic balance and health.
2)Activates plant protection and defense mechanisms.
3)Regulates stomatal opening and provides carbon skeleton prerequisites for cytokinin co-catalyzed enzymes.
Isoleucine
Acts as a regulatory amino acid that balances intrinsic plant mechanisms, improves leaf characteristics, provides an energy response, and enhances resistance to salt stress.
Leucine
Improves pollen viability and germination, especially at flowering and fruiting stages to enhance flowering and reduce late fruit abscission.
Lysine
1)Provides resistance in harsh environments, especially drought conditions.
2)Associated with chlorophyll synthesis and enhances its synthesis efficiency.
3)Plays a catalytic role in nitrogen uptake.
Methionine
1)Promotes fruit ripening and color formation.
2)Acts as a precursor for the synthesis of the endogenous plant hormones ethylene and polyamines.
Favors root growth by means of fertilization through irrigation and is associated with nitrate uptake.
Proline
1)Acts as an internal homeostatic regulator in plant response to stress, improves osmotic stress tolerance, and is suitable for application under drought, low temperatures, wind damage, or other adversity.
2)Improves overall plant stress tolerance and pollen vigor.
Serine
1)Acts as a precursor substance for the synthesis of other amino acids.
2)Involved in the regulation of plant defense mechanism against animal invasion and mechanical damage, etc.
3)Promotes cell tissue differentiation and germination processes.
Tyrosine
1)Provides energy for plant metabolism and has stress and shock resistance activity.
2)Acts as a precursor of plant defense system and enhances drought tolerance.
3)Improves pollen germination quality.
Threonine
1)Promotes plant growth.
2)For situations where plant growth is stagnant or in need of stimulation.
3)Enhances tolerance to adversity such as pests, diseases and environmental stresses and promotes organic matter decomposition processes.
Tryptophan
1)Is a precursor of the endogenous hormone growth hormone indoleacetic acid and promotes the synthesis of aromatic compounds.
2)Activates plant defense pathways in response to external aggressions such as animal attack, mechanical damage and drought.
Valine
1)Promotes and enhances seed germination and can be used in soaking treatments or applied with water for irrigation.
2)Helps plants resist cold stress and other stresses.
3)Improves crop flavor and quality.