Diurnal decline in the photosynthetic capacity of uppermost leaves in an eggplant canopy grown in a horticultural greenhouse NOMURA K. author SAITO M. author ITO M. author YAMANE S. author IWAO T. author TADA I. author YAMAZAKI T. author ONO S. author YASUTAKE D. author KITANO M. author text journal article 2022 Parameters representing leaf photosynthetic capacity, namely, the maximal carboxylation rate (V<sub>cmax</sub>), maximal electron transport rate (J<sub>max</sub>), and triose phosphate-utilization rate (T<sub>p</sub>), can vary depending on various factors. The present study investigated diurnal variations in V<sub>cmax</sub>, J<sub>max</sub>, and T<sub>p</sub> of uppermost leaves of soil-grown, well-watered eggplant in a greenhouse based on the simultaneous measurements of leaf gas exchange and chlorophyll fluorescence. The values of net photosynthetic rates and electron transport rates plotted against intercellular CO<sub>2</sub> concentrations were noticeably higher in the morning than in the afternoon. Significant differences were detected among the values of V<sub>cmax</sub>, J<sub>max</sub>, and T<sub>p</sub> obtained at different times of day (08:30, 11:00, 13:30, and 16:00 h). All three parameters tended to decline as the time of day advanced; compared to the values at 08:30 h, V<sub>cmax</sub>, J<sub>max</sub>, and T<sub>p</sub> declined by approximately 15% at 16:00 h. Among the three parameters, T<sub>p</sub> appeared to be the most sensitive to time. CO2-photosynthesis curve; diurnal variation; Farquhar-von Caemmerer-Berry photosynthesis model; horticultural crop; photosynthesis limitation; triose phosphate utilization. 10.32615/ps.2022.040 https://ps.ueb.cas.cz/artkey/phs-202203-0014.php https://ps.ueb.cas.cz/artkey/phs-202203-0014.php Photosynthetica continuing 60 3 457 464 2022 03003604 periodical academic journal