• Arginine is an amino acid – one of the building blocks of proteins.
• It is the most nitrogen-rich amino acid in nature (four nitrogen atoms per molecule).
• In plants, arginine is used as a storage and transport form of nitrogen, and as a direct nitrogen source when present in soils.

(Evolutionary perspective – the selective value of the arginine response)

• Efficient nitrogen storage and transport: Plants evolved to use arginine as a storage compound to buffer against seasonal fluctuations in nutrient supply and as a transport compound to efficiently transport nitrogen within the plant.
• Nutrient alignment with soil reality: Boreal and forest soils are dominated by organic nitrogen, including amino acids. Plants that can use arginine directly are better adapted to these conditions.
• Microbial partnerships: Arginine supports beneficial fungi and bacteria, improving access to water and nutrients.
• Stress resilience: Plants that can utilize arginine as a long-term nitrogen store are more resilient in nutrient-poor ecosystems.
• Root growth stimulation: Arginine is largely immobile in soils and hence plants that grow more roots and more root hairs, increasing the root surface area for nutrient and water uptake prevail.

Selective value: Plants that can use arginine efficiently gain a survival advantage in nutrient-limited environments.

• Direct uptake: Roots absorb intact arginine via amino acid transporters, Amino acid permeases (AAP´s; in particular AAP5).
• Soil retention: Unlike nitrate, arginine binds to soil particles, preventing leaching and keeping nitrogen in soil.
• Microbial attraction: Arginine draws in and nourishes mycorrhizal fungi and symbiotic bacteria such as Rhizobium, strengthening symbiotic nitrogen supply.
• Nutrient complexation: In formulations such as arginine-phosphate and arginine–iron–hexametaphosphate, arginine forms a slow-release nutrient matrix, synchronizing supply with uptake.

• Positive charge: Arginine is cationic at normal soil pH, so it sticks to negatively charged soil particles. It’s strong binding - adsorption to peat and organic matter reduces mobility compared to nitrate.
• Low diffusion: Arginine moves slowly in soils, staying where applied rather than washing away.
• Accumulation and slow release: Bound arginine can be dissolved over time, releasing nitrogen gradually.

Result: Arginine acts as a stable, rechargeable nitrogen battery in soils.

• Energy cost of uptake: Nitrate (NO₃⁻) must first be reduced to nitrite (NO₂⁻) and then to ammonium (NH₄⁺) before assimilation. These reduction steps consume large amounts of energy (in the form of NADH and ATP).
• Ammonium toxicity: While ammonium can be taken up directly, high levels are toxic to roots and disrupt pH balance.
• Arginine advantage: Arginine provides ready-made reduced nitrogen in an organic form, bypassing the costly nitrate reduction steps and avoiding ammonium toxicity.
• Carbon bonus: Unlike nitrate or ammonium, arginine also supplies carbon skeletons, improving energy efficiency of assimilation.

In biological terms, arginine is a low-cost, high-value nitrogen source that saves plants metabolic energy and supports growth more efficiently than nitrate or ammonium.

• Compared to ammonium: Arginine is more stable, less prone to volatilization, and safer for roots. It also doubles as a nitrogen storage form, unlike ammonium.
• Compared to nitrate: Arginine avoids costly reduction steps and leaching losses. It remains bound in soils, reducing nitrogen runoff and increasing long-term nitrogen availability.
• Overall advantage: Arginine combines stability, energy efficiency, and plant preference, making it superior to both ammonia and nitrate for sustainable plant nutrition.

• Amino acid biostimulants: Most commercial amino acid biostimulants provide free amino acids, including arginine, that can stimulate growth but are often released quickly and complex mixtures contain both beneficial amino acids and amino acids that have negative effects on plant growth.
• Arginine–phosphate (Arevo): Combines arginine with phosphate (and in some formulations, iron), forming a stable complex that provides controlled, long-lasting release of nutrients around the seed or in the root zone.
• Key difference: Arginine phosphate is a stable formulation, well-defined with constituents that only have positive effects on plants, while complex mixtures contain compounds with both negative and positive effects.

• Protein hydrolysates: Most amino acid biostimulants are produced by breaking down animal by-products. This process yields a mixture of amino acids and peptides, often inconsistent in purity and composition.
• Bacterial fermentation (used in Arevo’s products): Uses microbes fed to produce pure arginine. This method ensures:
  • High purity and consistency.
  • Minimal risk of contaminants (heavy metals, pathogens).
  • Controlled and scalable production.
• Key difference: Hydrolysates are complex, variable mixtures, while fermentation delivers targeted, pure arginine optimized for plant nutrition.

• Arginine (free form): A single amino acid, highly nitrogen-rich, taken up directly by plants and microbes. It is mobile in living tissues but binds to soil particles.
• Arginine phosphate (complex form): A chemical complex of arginine with phosphate. This pairing creates a slow-release nutrient matrix, keeping both nitrogen and phosphorus available over longer periods.
• Implication: Arginine provides the nitrogen, while arginine phosphate delivers balanced, multi-nutrient support with improved stability.

• Forestry: Aligns seedling nutrition with natural soil nitrogen forms, improving establishment and survival.
• Agriculture: Crops like soy, corn, wheat, barley, oilseed rape, and potato can directly take up amino acids (including arginine) under field conditions. This improves nitrogen use efficiency, reduces leaching, and provides farmers with a sustainable way to grow food profitably while protecting farmland for future generations.
• Sustainability: Cuts nitrate leaching and prevents water pollution.
• Efficiency: Provides both nitrogen and carbon skeletons, making uptake more energy-efficient than nitrate or ammonium.
• Resilience: Strengthens roots, microbial networks, and plant defenses for long-term ecosystem and farm health.

Sources

• Ganeteg, U., Ahmad, I., Jämtgård, S., Aguetoni-Cambui, C., Inselsbacher, E., Svennerstam, H., Schmidt, S., & Näsholm, T. (2016). Amino acid transporter mutants of Arabidopsis provide evidence that a non-mycorrhizal plant acquires organic nitrogen from agricultural soil. Plant, Cell & Environment, 39(12), 2580–2590. https://doi.org/10.1111/pce.12738
• Hobbie, E. A., & Högberg, P. (2012). Nitrogen isotopes link mycorrhizal fungi and plants to nitrogen dynamics. New Phytologist, 196(2), 367–382. https://doi.org/10.1111/j.1469-8137.2012.04292.x
• Näsholm, T., Kielland, K., & Ganeteg, U. (2009). Uptake of organic nitrogen by plants. New Phytologist, 182(1), 31–48. https://doi.org/10.1111/j.1469-8137.2008.02751.x
• Tünnermann, L., Franklin, O., Näsholm, T., & Högberg, P. (2024). Plant organic nitrogen nutrition: Costs, benefits, and carbon use efficiency. New Phytologist, 241(2), 303–317. https://doi.org/10.1111/nph.19425
• Arginine–iron–hexametaphosphate complex as a novel nitrogen plant nutrition reducing nitrate leaching in Scots pine (Pinus sylvestris) seedling production. (2024). Scientific Reports.
• Uptake of organic nitrogen in the field by four agriculturally important plant species.
• Uptake of glycine by field-grown wheat. 
• Franklin et al. “The carbon bonus” https://onlinelibrary.wiley.com/doi/10.1111/pce.12772