The answer to your question is organic acids. Organic acids are produced by some plant roots as a natural process. These acids play various roles in plant growth and development, including nutrient uptake and defense against pathogens. If you'd like to know more about the specific types of organic acids produced by plant roots, it would be helpful to search for scientific articles or books on plant physiology or biochemistry. Additionally, you can consult botanical databases or websites that provide information on plant characteristics and adaptations.
