What is Plasma Activated Water?

Plasma Activated Water (PAW) is a liquid containing antimicrobial properties suitable for disease control in agriculture crops. The only required components for making PAW are water, ambient air and electricity. Ambient air is brought into plasma phase with electrical energy and then fixated in water. Reactive Oxygen and Nitrogen Species (RONS) dissolve into the water creating PAW.

This process of treating water with plasma is copied from nature. It’s a biomimicry of a thunderstorm where rain and water get into contact with lightning (a plasma). After the activation process, PAW possesses unique temporary properties that have antimicrobial action. PAW has a strong but short-lived effect on plant health, and leaves only nitrate as a residue which is a nutrient for the plant and fully absorbed.

What does PAW do to fungal spores?

The mode of action of PAW involves the creation of reactive species that exert antimicrobial effects on pathogens while also stimulating beneficial responses in plants. This supports disease prevention, enhances plant health, and contributes to better yields. The RONS in PAW can inactivate microbes either by directly disintegrating the outer membrane or via an intracellular mechanism, preventing microbial growth and reproduction.

RONS can enter the fungal cell due to (1) reduced membrane integrity, (2) through active transport via pores, or (3) via diffusion. Intracellular, these RONS accumulate and lead to a decrease in pH and oxidize DNA, proteins and lipids, thereby breaking DNA, disintegrating proteins and triggering lipid peroxidation. By inducing intracellular oxidative stress, the membrane potential decreases, which results in a breach of membrane integrity. Fragmentation of the cell membrane and other cellular components results in content leaking out of the microbes, resulting in spore death.

PAW acts asa broad-spectrum solution against different types of sporulating bacteria and outside plant-tissue fungal colonizers. Within a few minutes spores are unable to germinate and infest new plant parts.

The effect on fungal spores can be clearly seen by means of electron microscopy. PAW treatment results in holes in the cell wall, causing spores to be irreversibly damaged and unable to germinate (Figure 1).

‍The 3 benefits of PAW on disease control in your crop

1. PAW prevents germination of spores within minutes. This prevents the spores from developing into harmful fungi or pathogens, immediately reducing the risk of crop contamination. This rapid effect helps maintain healthy plant growth and protects against potential diseases.
2. PAW reduces the infection rate on a plant. Due to its effectiveness in preventing spore germination, the chance of infection is significantly reduced. This ensures a healthier harvest, less loss due to disease and improved overall plant health.
3. PAW limits the spread of spores in a greenhouse. In a controlled environment such as a greenhouse, it is important to minimize the spread of pathogens. This prevents the spread of spores between plants, resulting in a cleaner and more controlled growing environment. This allows the plants to recover more quickly from any damage and greatly reduces the risk of large-scale contamination.

Including PlasmaActivated Water in disease management programs contributes to more optimal growing conditions for plants and accelerates the transition to more sustainable crop protection.

‍References

1. Ki, S. H., Noh, H., Ahn, G. R., Kim, S. H., Kaushik, N. K., Choi, E. H., & Lee, G. J. (2020). Influence of Nonthermal Atmospheric Plasma-Activated Water on the     Structural, Optical, and Biological Properties of Aspergillus brasiliensis Spores. Applied Sciences, 10(18), 6378. https://doi.org/10.3390/app10186378 

2. Köhl, J. P.H.B. de Visser & J. Wubben (2007). Risico’s op schimmelaantasting in vruchtgroenten: literatuurstudie. Rapportage van project ‘Risicoschatter voor schimmelaantasting in vruchtgroenten: voorfase’ van onderzoekprogramma Energie (LNV-DK-03-06). Nota 467. 

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