Excessive soil salinity poses a significant threat to crop growth, causing what is known as salt stress. This condition adversely affects plants by leading to water deficiency, the suppression of photosynthesis, worsened respiration, breakdown of chlorophyll, and the leakage of potassium ions.
Additionally, the presence of water-soluble toxic salts triggers the synthesis of reactive oxygen species, which can result in cell damage. In the context of climate change, there is a growing concern about the expansion of saline lands around the world.
To address this issue, agronomists from RUDN University collaborated with researchers from Egypt, Kazakhstan, and Russia, and they have made a notable breakthrough. They found that organic amino acids, also known as biostimulants, can effectively mitigate the harm caused by salt stress. Their findings were published in the journal Horticulturae.
Salinization is a problem affecting over 6% of the Earth's land, making it a critical concern for agriculture. Biostimulants have gained attention in research circles due to their potential to offer a sustainable solution for countering the effects of toxins and biotic stress, ultimately enhancing water and nutrient absorption.
Substituting synthetic chemicals with biostimulants for salt stress mitigation is seen as a key approach to promoting sustainable agriculture.
The agronomists conducted experiments to simulate salt stress and cultivated lettuce (Lactuca sativa) in such conditions. They then applied six amino acids - alanine, arginine, glutamine, glycine, methionine, and proline - at a concentration of 0.5 grams per liter by spraying the lettuce.
After the experiments, the researchers assessed various parameters, including the activity of photosynthetic pigments, ion absorption levels, endogenous amino acid content, and the activity of catalase and peroxidase enzymes, which are crucial for regulating oxidative processes and respiration in plants.
Glycine, methionine, and proline emerged as particularly beneficial amino acids. Their application mitigated the increase in electrical conductivity induced by salt stress. The concentration of chlorine anions decreased by 25% when compared to lettuce which was not treated with amino acids.
Moreover, the absorption of potassium cations improved, and there was an increase in the concentration of chlorophyll. Methionine and proline also led to an increase in the production of the plant's own amino acids.
In conclusion, the use of amino acids had a positive impact on the growth, physiological, and biochemical characteristics of lettuce under salt stress conditions. The researchers recommend spraying lettuce crops with methionine or proline at a concentration of 0.5 grams per liter to reduce the detrimental effects of salt stress.
However, it's important to note that this study represents only a portion of the broader research needed to address the potential challenges posed by salinity due to climate change.
