Illuminating Indoor Tropicals: Characterizing Photosynthetic Light Responses in High-value Houseplants

Optimizing supplemental lighting for tropical foliage requires quantifying photosynthetic responses under controlled conditions. This study evaluated photosynthetic light response (A/Q i ) curves for 12 common houseplants, including Philodendron spp., Monstera spp., Syngonium podophyllum , and Goeppertia spp. Net CO 2 assimilation was measured using a portable gas-exchange system. The light compensation point ( I c ), light saturation point ( I sat ), and light-saturated assimilation rate ( A sat ) were derived from nonlinear fits using logistic and rectangular hyperbola formulations. The 12 houseplants showed considerable variability, with I c ranging from 4 to 12 μmol·m −2 ·s −1 , I sat from 145 to 621 μmol·m −2 ·s −1 , and A sat from 1.9 to 7.6 μmol CO 2 ·m −2 ·s −1 . Syngonium exhibited the highest I sat (413 μmol·m −2 ·s −1 ) whereas Goeppertia exhibited the lowest (249 μmol·m −2 ·s −1 ). These results provide physiological benchmarks for improving lighting efficiency in greenhouse and interior environments.