Composition of organic acids secreted by alpine shrub roots and its influencing factors

Background and aims: There appears to be a strong correlation between the rapid proliferation of shrubs in the alpine grassland of the Qinghai-Tibet Plateau and the root exudates of these plants. The dynamics of root exudates during shrub development, however, have been the subject of few investigations. Methods: This work examined Lonicera thibetica, a plant found on the eastern edge of the Qinghai-Tibet Plateau. It focused on the root systems of 5-, 10-, 15-, and 20-year-old L. thibetica plants and how their primary organic acid components changed with the seasons and other circumstances. Results: The findings revealed that the primary components of acid secretion in the roots of L. thibetica were oxalic acid, lactic acid, and tartaric acid; of these, oxalic acid made up over 50% of the total organic acid content. The levels of these organic acids often dropped as shrubs got older, and their seasonal dynamics exhibited a parabolic shift pattern, typically peaking during the robust development stage. According to regression analysis, soil moisture was the primary determinant of the concentration of organic acids produced by alpine shrub roots, suggesting that soil moisture played a crucial role in the secretion process. Conclusions: The physiological dynamics of roots and the mechanisms that regulate them throughout the expansion of alpine shrubs can be better understood thanks to this work.