Drought reduces rice (Oryza sativa L.) productivity by impairing leaf water status, activating abscisic acid (ABA)-mediated stomatal closure, and disrupting carbon-water trade-offs. Rice adapts to drought through rapid stomatal signaling, developmental modifications, and whole-plant integration of hydraulic regulation, mesophyll conductance, and canopy architecture. Growing evidence indicates that moderate reductions in stomatal density (SD) can enhance water-use efficiency (WUE) and drought tolerance with minimal yield penalties when coordinated with non-stomatal traits. However, extreme reductions in SD may restrict carbon assimilation and impair thermoregulation. Recent studies have identified SD-related quantitative trait loci (QTLs) and candidate genes, alongside successful genome editing of EPF/EPFL family members, providing valuable targets for drought-resilient rice breeding. Rice deploys morphological, physiological, and molecular strategies to maximize WUE while sustaining photosynthesis under drought, including SD and aperture modulation, ABA and reactive oxygen species (ROS)-mediated signaling, and transcriptional regulation of drought-responsive genes and transcription factors. Despite these advances, key challenges remain in integrating stomatal traits with whole-plant hydraulics, root architecture, reproductive resilience, and genotype-by-environment interactions under field conditions. Future breeding strategies should combine physiological phenotyping with genomics, genome editing, and digital agriculture tools to develop climate-resilient rice cultivars capable of sustaining productivity under drought.

Keywords: Rice (O. sativa L.), stomata, drought stress, ABA-signaling, guard cells, drought tolerance

Key findings: Drought reduces rice (O. sativa L.) productivity by lowering leaf water status and inducing ABA-mediated stomatal closure, disrupting carbon-water balance. Moderate reductions in stomatal density enhance water-use efficiency and drought tolerance with minimal yield penalty, whereas excessive reduction limits carbon assimilation.