A Dose-Response Framework for Ca2+-ROS-Associated Modulation of Aerenchyma Formation Under Flooding Stress.

Flooding stress associated with climate variability requires a better understanding of adaptive plant responses and their regulation in flood-prone systems. This study examines whether dose-dependent modulation of Ca2+/ROS-associated processes influences root porosity and biomass responses in Cynodon dactylon under flooding-related stress. Systematic modulation of Ca2+-ROS-associated processes was examined using CaCl2, 3-amino-1,2,4-triazole (AT), EGTA, and diphenylene iodonium. The core novelty lies in translating biological signalling into an actionable bioprocess optimisation framework using Hill/EMAX dose - response modelling and benchmark dose (BMD) analysis. This methodology defined precise efficacy - safety windows for chemical application. Principal results demonstrate that low doses of CaCl2 and the ROS inducer AT significantly enhanced root porosity without compromising biomass. Critically, the BMDporosity+10 (required dose for 10% porosity gain) was robustly positioned to the left of BMDbiomass-10 (dose causing 10% growth penalty), confirming a safe and effective operational zone. These results provide a quantitative basis for future validation of dose-dependent Ca2+/ROS modulation under more complex environmental conditions.