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. This study is the first to systematically evaluate the tolerance strategies of ornamental flowering plants to ambient air pollution by integrating physiological and biochemical responses with established indices (APTI and API) and random forest modeling.Unlike prior work that has primarily focused on trees and shrubs, this research demonstrates that ornamental flowers—Rosa indica, Jasminum sambac, and Polianthes tuberosa—exhibit distinct, species-specific adaptive mechanisms at their flowering stage, a critical and pollution-sensitive phase. The study not only identifies resilient floral species suitable for parks, rooftops, and vertical greenery systems in polluted urban environments but also introduces an evidence-based framework for linking physiological integrity with pollution tolerance.To our knowledge, this is the first report from the Indian subcontinent highlighting the application of flowering ornamentals in vertical greenery as a sustainable strategy for urban air quality management. This study is the first to systematically evaluate the tolerance strategies of ornamental flowering plants to ambient air pollution by integrating physiological and biochemical responses with established indices (APTI and API) and random forest modeling. Unlike prior work that has primarily focused on trees and shrubs, this research demonstrates that ornamental flowers—Rosa indica, Jasminum sambac, and Polianthes tuberosa—exhibit distinct, species-specific adaptive mechanisms at their flowering stage, a critical and pollution-sensitive phase. The study not only identifies resilient floral species suitable for parks, rooftops, and vertical greenery systems in polluted urban environments but also introduces an evidence-based framework for linking physiological integrity with pollution tolerance. To our knowledge, this is the first report from the Indian subcontinent highlighting the application of flowering ornamentals in vertical greenery as a sustainable strategy for urban air quality management.