The Essence of Nature Can Be the Simplest (7)—Plant Growth: Powered by Extracellular Fenton Chemistry

Plants serve as fundamental engineers of the biosphere, orchestrating processes essential for planetary function and the sustenance of life. They exhibit a notable morphological paradox: Aboveground structures (primarily photosynthetic shoots) display remarkable diversity in architecture and organ specialization, whereas belowground structures (primarily heterotrophic roots) often demonstrate striking conservation and convergence across phylogenetically distant taxa. This article synthesizes current knowledge on the dynamic patterns of ATP in photosynthetic and heterotrophic tissues driven by diurnal cycles, as well as variations in iron concentrations across different plant organs and tissues. By integrating molecular, physiological, and thermodynamic perspectives, the article proposes that shoots transition from ATP synthesis during the day to extensive extracellular Fenton chemistry at night, thereby coping with the substantial temperature decline. In contrast, roots, buffered by the insulating properties of soil, experience relatively minor fluctuations in the intensity of extracellular Fenton chemistry. Furthermore, critical life cycle transitions, including germination and flowering, are strongly influenced by extracellular Fenton chemistry. Elucidating the energetic mechanisms underlying these dynamic processes is essential for understanding plant biodiversity, advancing sustainable resource management, and enhancing plant adaptability in extreme environments, and revealing the chemical and energy rationales underlying the therapeutic principles of Traditional Chinese Medicine for disease treatment.