Science has uncovered a surprising plant superpower: they slurp up small peptides faster than amino acids! This nutrient uptake shortcut has become a major research focus, with scientists racing to decode how—and why—plants evolved this clever feeding trick.
Comparison between small peptides and amino acids
Structure
Small peptides are peptide chains with a length of 2-50 amino acids and have high biological activity.
They are usually composed of multiple amino acid residues and can be expressed as NH2-CHR-CO-NH-CHR1-COOH (where CHR is a hydrophobic amino acid and CHR1 is a hydrophilic amino acid).
The structure of small molecule peptides can significantly affect their physical and chemical properties and biological activity.
While amino acids are the basic building blocks of proteins, consisting of an amino group and a carboxyl group connected to the same carbon atom.
Different types of amino acids have different R-group side chains, which determine the physical and chemical properties and biological activity of amino acids.
Properties
Small molecule peptides and amino acids are both hydrophilic and hydrophobic, but the former are more hydrophilic.
Small molecule peptides also have lower polarity and higher stability, which make it easier for them to pass through the cell membrane and enter plant cells.
Stability
The stability of small molecule peptides is affected by multiple factors, such as temperature, pH, enzyme activity, etc. Under certain conditions, they can be degraded into single amino acids, but compared with amino acids, they are more stable.
Factors affecting absorption rate
Hydrophilicity
Small molecule peptides are generally more hydrophilic than amino acids, which allows them to better bind to water channel proteins on plant cell membranes, thereby accelerating the absorption rate.
Transmembrane transport
Small molecule peptides may enter plant cells through active transport or endocytosis, while amino acids mainly enter cells through active transport. Active transport requires the participation of carrier proteins, while small molecule peptides may use more transport protein channels for transmembrane transport. Therefore, small molecule peptides may enter plant cells through more efficient transmembrane transport.
Energy supply
After entering plant cells, small molecule peptides may be more easily broken down into single amino acids than amino acids, because the decomposition products of small molecule peptides can generate more energy to supply plants. In addition, the decomposition process of small molecule peptides may involve less energy consumption, so their absorption efficiency is higher.
All in all，from many perspectives, plants absorb small molecule peptides faster than amino acids. Although they are both important sources of nutrition for plants, in some cases, small molecule peptides have a higher absorption rate and efficiency than amino acids. This phenomenon is related to factors such as the hydrophilicity of small molecule peptides, transmembrane transport mode, and energy supply.
In actual agricultural production applications, although small molecule peptides are superior to amino acids in terms of absorption efficiency and stability, amino acids also have their own irreplaceable advantages.
In order to maximize the efficacy of biostimulant products, it is an effective method to organically combine small molecule peptides and amino acids.
This combination can make the two nutrients complement each other and exert the maximum combined effect.
For example, the YPD-360 formula of the amino acid peptide finished preparation of LYS Ecology is a good example. It contains free amino acids ≥140g/L and 360g/L of peptides.
The combination of these free amino acids and peptides can greatly improve the utilization rate of nutrients and promote the growth and development of plants.
