Colored Leaves of Epipremnum aureum Reveal Contrasting Dynamic Photosynthetic and Water-Use Strategies

Leaves normally operate under temporally heterogeneous light and experience frequent dark-light transitions as the incident irradiance fluctuates on time scales of seconds to minutes. Under such conditions, the kinetics of photosynthetic induction and stomatal adjustment influence carbon gain, water loss, and intrinsic water-use efficiency (iWUE); however, colored leaves have rarely been examined from this dynamic perspective. We compared three cultivar-associated leaf-color phenotypes of Epipremnum aureum (Linden & André) G.S. Bunting (Neon, Golden, and Jade cultivars) during a 150 min dark-light-dark sequence. Time-resolved net CO₂ assimilation (A), stomatal conductance (g _s), transpiration (E), iWUE, and chamber leaf temperature were analyzed together with photosynthetic pigments, hyperspectral reflectance, and stomatal and epidermal anatomy. The total chlorophyll and normalized difference vegetation index-type indices increased from Neon to Golden to Jade, whereas the area-based carotenoids and visible reflectance decreased. Steady-state A ranged from ≈1.3 μmol CO₂ m^-2 s^-1 in Golden to ≈6.0 μmol CO₂ m^-2 s^-1 in Neon. Neon also showed the fastest photosynthetic induction, the highest steady-state iWUE, the lowest E during illumination, and the slowest stomatal closure after darkening. Jade showed intermediate A and g _s, the highest illuminated E, slower induction, and the fastest closure, whereas Golden had the lowest A and g _s, the smallest dynamic ranges, and intermediate E despite high abaxial stomatal density and sparse trichomes. These cultivar-associated pigment, optical, anatomical, and physiological traits formed distinct covarying profiles during light transitions. Owing to color-genotype confounding, colored pothos cultivars provide a practical comparative system for studying dynamic photosynthesis and water use under fluctuating light.