Root response to acid stress and the mechanism of acid tolerance regulated by boron

The application of N fertilizer increases crop yield and simultaneously leads to soil acidification. The pH values of farmlands in China have decreased by 0.42 in the past 20 years. H⁺ directly acts on the root cell wall, induces cell death by destroying the cell wall's structural stability, and thus inhibits elongation of root and absorption of nutrients and water. Consequently, the growth and development of plants and the yield and quality of agricultural produce are impacted. Therefore, exploring the mechanism of stress response in plants is essential for making the right counter-measurement. This paper summarizes the internal regulation of plants and their response to acid stress and the mechanism of boron in improving plant acid tolerance. The signal transduction of plants through Ca²⁺ and K⁺ channels can respond to pH changes and regulate them in gene and protein levels to respond to acid stress quickly. Moreover, recent studies have shown that boron can alleviate plant acid stress. This is achieved by regulating the secretion of organic acids in plant roots, changing cell wall characteristics, maintaining cell wall structure and stability, stimulating ethylene and class III peroxidase (CIII Prxs) metabolism, etc. At present, the research on plant acid stress is gradually deepening, but the changes of plant root metabolites under acid stress and the induction mechanism are not clear, and the specific genes responding to low pH are not clear, so further research is needed.