In a long-standing concept, it is generally believed that plants cannot directly absorb organic nitrogen, such as amino acids, but need to be converted into simple inorganic nitrogen through mineralization before it can be absorbed. However, an increasing number of experiments have shown that in many soil systems, the absorption of amino acids as a nutrient nitrogen source by plants accounts for a considerable proportion of total nitrogen source utilization, especially in soil systems with relatively scarce nitrogen sources, where the The role of amino acids cannot be ignored.
With the deepening of research, people have discovered that amino acids are not only organic nitrogen sources for plants, but also have multiple functions, including participating in protein synthesis and regulating plant growth. Different types of amino acids also have different physiological functions on crops:
- Alanine: Increases chlorophyll synthesis, regulates stomata opening, and fights pathogens.
- Arginine: Enhances root development, is a precursor for polyamine synthesis, and improves salt stress resistance.
- Aspartic acid: promotes seed germination and provides a source of nitrogen for growth during periods of stress.
- Cysteine: maintains cell function and acts as a sulfur antioxidant.
- Glutamic acid: Reduces nitrate content and promotes leaf photosynthesis.
- Glycine: has a unique effect on photosynthesis and increases sugar content.
- Histidine: regulates stomatal opening and provides the precursor of carbon skeleton hormones.
- Isoleucine and leucine: improve resistance to salt stress and increase pollen vitality.
- Lysine: Enhances chlorophyll synthesis and improves drought tolerance.
- Methionine: precursor for polyamine synthesis.
- Phenylalanine: Promotes lignin synthesis, the precursor of anthocyanins.
- Proline: Increases plant tolerance to osmotic stress, improves stress resistance and pollen viability.
- Serine: Participates in cell tissue differentiation and promotes germination.
- Threonine: Improves tolerance and protects against pests and diseases.
- Tryptophan: a precursor for the synthesis of auxin indole acetic acid, improving the synthesis of aromatic compounds.
- Tyrosine: Increases drought tolerance and improves pollen germination.
- Valine: Increases seed germination rate and improves crop flavor.
There are also synergistic effects between these amino acids, such as promoting chlorophyll production, plant endogenous hormone formation, root development, seed germination, flowering and fruiting, and improvement of fruit flavor, etc.
Regarding amino acid fertilizers, you need to understand a few concepts first: Amino acids are the basic units of protein and are easy to absorb. Small molecule peptides are composed of 2 to 10 amino acids and are also called oligopeptides. Polypeptides are composed of 11 to 50 amino acids and have relatively large molecular weights. Protein consists of more than 50 amino acids and cannot be directly absorbed by plants.
The methods of using amino acid fertilizers include drip irrigation, flushing, and foliar spraying. They are suitable for top dressing rather than basal fertilizer. When choosing fertilizers, small molecule peptides can be selected according to actual conditions to resist adverse environments and improve crop stress resistance, while ordinary amino acid fertilizers are more suitable for improving fertilizer efficiency. When using amino acid fertilizers, pay attention to timely application, because it is easy to be decomposed by microorganisms after being exposed for a long time.
In general, exogenous application of amino acid fertilizers is very necessary to exert plant physiological regulation functions, increase yields, and enhance stress resistance.
