Acclimation to high light intensity increases leaf photosynthetic capacity and NPQ kinetics, but barely affects photosynthetic induction rate

Crops often grow under fluctuating irradiance, requiring photosynthesis to dynamically adjust to these fluctuations. However, to what extent acclimation to different growth irradiances affects this dynamic response remains unclear. To elucidate this, three widely cultivated horticultural crops (cucumber, tomato, and sweet pepper) were grown under three irradiances (100, 300, and 600 μmol m −2 s −1 ). Leaf morphology, pigmentation, steady-state and dynamic photosynthetic gas exchange, and chlorophyll fluorescence were analyzed. In all three species, higher irradiance significantly increased leaf pigment concentration, light-saturated net photosynthesis rate ( A sat ), mitochondrial respiration rate ( R d ), maximum carboxylation rate ( V cmax ), electron transport rate at high irradiance ( J 1500 ), maximum rate of triose phosphate use (TPU), and the rates of non-photochemical quenching (NPQ) induction. However, different growth irradiances had few effects on the optimization of quantum yield of CO 2 assimilation ( Φ CO2 ) and photosynthetic induction rates. Only cucumber leaves grown under 600 μmol m −2 s −1 exhibited a slower photosynthetic induction rate ( t 90 , time to reach 90 % of full photosynthetic induction) compared to those grown at lower irradiances, due to reduced stomatal opening speed and stronger biochemical limitation. Our findings enhance the understanding of photosynthetic acclimation to growth irradiance, provide options for optimizing supplemental lighting in greenhouses and the controlled environment agriculture, and offer insights for modeling photosynthesis under both steady and fluctuating irradiance. • Acclimation to high light intensity barely affected photosynthetic induction rate. • High light acclimation significantly increased non-photochemical quenching induction rates. • Growth light intensity did not optimize the quantum yield of CO 2 assimilation at the corresponding growth irradiance.