A biostimulant containing L-valine

Biostimulants containing L-valine, as a new type of plant growth regulator, exhibit unique effects in enhancing crop stress resistance (such as drought, salinity, low temperature, pests, and diseases) by regulating crops' own physiological metabolism and signaling pathways. Their impact mechanisms and application characteristics can be elaborated as follows:

I. Resistance to Abiotic Stress: From Physiological Metabolism to Signal Regulation

Abiotic stresses (drought, salinity, low temperature, etc.) cause crop cell dehydration, oxidative damage, and metabolic disorders. Biostimulants containing L-valine alleviate stress damage mainly through the following pathways:

Enhanced Osmotic Regulation: As an amino acid substance, L-valine directly participates in the synthesis of intracellular osmotic solutes, increasing cell osmotic pressure and reducing water loss under drought or saline-alkali conditions. For example, under drought stress, application of L-valine-containing biostimulants can increase the content of osmoprotective substances such as proline and soluble sugars in wheat leaves by 20%-30%, maintaining cell structural integrity.

Activation of Antioxidant Systems: In stressful environments, the accumulation of reactive oxygen species (ROS) in crops triggers membrane lipid peroxidation. L-valine can induce increased activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) (some studies show enzyme activity can be enhanced by over 40%), while promoting the synthesis of non-enzymatic antioxidants like glutathione, thereby reducing ROS damage to cell membranes and organelles.

Regulation of Stress Signal Pathways: L-valine derivatives can enhance crop responses to low-temperature stress by regulating the synthesis of plant hormones (such as ABA and salicylic acid). For example, under low-temperature stress in rice, such biostimulants can upregulate the expression of cold-responsive genes (e.g., OsICE1), reduce cell freeze damage, and increase seedling survival rate by 15%-25%.

II. Resistance to Biotic Stress: Strengthening Immunity and Defense Mechanisms

In the case of biotic stresses such as pests and diseases, biostimulants containing L-valine enhance crops' resistance to pathogens and pests by activating their own immune systems:

Inducing Phytoalexin Synthesis: As a precursor for secondary metabolism, L-valine can promote the synthesis of phytoalexins (such as isoflavones and phytoalexin A), which directly inhibit fungi (e.g., powdery mildew pathogens) and bacteria (e.g., bacterial wilt pathogens). For example, after application on tomatoes, the content of phytoalexins in leaves increases significantly, with a control effect of over 60% on late blight, reducing the use of chemical fungicides.

Enhancing Cell Wall Structure: It can stimulate crops to synthesize lignin and cellulose, thickening cell walls to form a physical barrier that blocks pest feeding or pathogen invasion. Studies have found that after spraying L-valine-containing biostimulants, the lignin content in cotton leaf cell walls increases by 18%-22%, significantly enhancing resistance to cotton bollworms.

Activating Systemic Acquired Resistance (SAR): By regulating the salicylic acid signaling pathway, crops develop systemic resistance after local infection, showing stronger defense capabilities against subsequent pest and disease attacks. For example, on tobacco, such biostimulants can induce the expression of PR proteins (pathogenesis-related proteins), with an inhibition rate of over 50% on tobacco mosaic virus (TMV).

III. Application Characteristics and Optimization Directions

The following points should be noted in the practical application of L-valine-containing biostimulants:

Application Methods and Timing: Foliar spraying or root irrigation is commonly used. Foliar spraying takes effect faster (physiological index changes can be detected within 24-48 hours), suitable for emergency stress resistance; root irrigation has a longer lasting effect (up to 2-3 weeks), suitable for long-term stress prevention. Application during crop stress-sensitive periods (such as seedling stage and flowering stage) yields better results.

Synergistic Effects: Combined use with other biostimulants (such as humic acid, seaweed extracts) or low-dose chemical pesticides can significantly enhance stress resistance effects. For example, after compounding L-valine with humic acid, the drought resistance of wheat is 15%-20% higher than that of using L-valine alone.

Safety and Environmental Friendliness: As a natural amino acid derivative, L-valine can be degraded by microorganisms in the soil without residual pollution, meeting the needs of green agricultural development and being particularly suitable for organic crop production.

Summary

Biostimulants containing L-valine demonstrate high efficiency and safety in resisting abiotic and biotic stresses by regulating crop physiological metabolism, activating antioxidant systems and immune pathways. Future research needs to further clarify their interaction mechanisms with crop gene expression, optimize formulations and application technologies, to better meet the demand for green stress resistance technologies in sustainable agricultural development.