Artificial light at night (ALAN) is an increasingly significant environmental disturbance, as it disrupts natural light-dark cycles that regulate daily and seasonal physiological processes and phenological events of all organisms. The use of artificial lighting in urban areas is rapidly increasing each year due to the rising number of unregulated vehicles, as well as the widespread installation of decorative lights, digital advertising boards, and streetlights. The objective of this research was to determine the impacts of artificial light at night (ALAN) on various ornamental garden plants such as Dieffenbachia seguine, Lawsonia inermis, Alocasia cucullata, Cynodon dactylon and Dypsis lutescens through the analyses of chlorophyll fluorescence transients, specific and phenomenological energy fluxes, density of functional PSII RCs, quantum yields (F/F, ϕE), non-photochemical quenching (Kn) and photochemical quenching (Kp), superoxide dismutase (SOD) activity, and concentrations of chlorophylls, malondialdehyde (MDA) and starch content. The results of the present study highlight that plant responses to ALAN vary among species. The present investigation demonstrates that D. lutescens and C. dactylon exhibit pronounced sensitivity to ALAN, whereas D. seguine, L. inermis, and A. cucullata display a comparatively higher degree of tolerance. These findings underscore the need to preferentially select ALAN-tolerant species for urban plantation programs to minimize the ecological consequences associated with light pollution. Moreover, the study identifies specific photosynthetic parameters (OJIP transients, ET/CS, RC/CS, Kp, Kn, and PI) along with key biochemical indicators (SOD activity, MDA accumulation, and chlorophyll content) as reliable diagnostic markers for distinguishing ALAN-sensitive and ALAN-tolerant species, thereby supporting informed species selection for sustainable urban greening. v m0CS
