Physiological and biochemical traits mediate species-specific air pollution tolerance in ornamental plants

Rapid urbanization has escalated air pollution, highlighting the need to identify resilient plant species for sustainable urban greening. This study evaluated the tolerance strategies of three ornamental plants Rosa indica, Jasminum sambac, and Polianthes tuberosa at their flowering stage under ambient air pollution. Physiological and biochemical traits were measured and integrated into the Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API). Particulate matter was the dominant pollutant at the study site compared to NO₂ and SO₂. Although APTI values did not differ significantly among species, their adaptive responses were distinct. Rosa indica maintained photosynthesis under stress, Jasminum sambac sustained gas exchange and water use efficiency, while Polianthes tuberosa relied on conserving relative water content and antioxidant defense but showed impaired stomatal conductance. API scoring classified Rosa indica and Jasminum sambac as good performers whereas Polianthes tuberosa was vulnerable. Random forest analysis was used for assessment of adaptive response and further identified species-specific predictors of tolerance, emphasizing photosynthesis in Rosa indica, stomatal traits in Jasminum sambac and antioxidant defense in Polianthes tuberosa. These findings propose Rosa indica and Jasminum sambac as promising candidates for parks, rooftops and vertical greenery, underscoring the role of floral ornamentals in air pollution mitigation.