PT  - JOURNAL ARTICLE
AU  - NOMURA, K.
AU  - SAITO, M.
AU  - ITO, M.
AU  - YAMANE, S.
AU  - IWAO, T.
AU  - TADA, I.
AU  - YAMAZAKI, T.
AU  - ONO, S.
AU  - YASUTAKE, D.
AU  - KITANO, M.
TI  - Diurnal decline in the photosynthetic capacity of uppermost leaves  in an eggplant canopy grown in a horticultural greenhouse
DP  - 2022 Sep 8
TA  - Photosynthetica
PG  - 457--464
VI  - 60
IP  - 3
AID - 10.32615/ps.2022.040
IS  - 03003604
AB  - Parameters representing leaf photosynthetic capacity, namely, the maximal carboxylation rate (V&lt;sub&gt;cmax&lt;/sub&gt;), maximal electron transport rate (J&lt;sub&gt;max&lt;/sub&gt;), and triose phosphate-utilization rate (T&lt;sub&gt;p&lt;/sub&gt;), can vary depending on various factors.  The present study investigated diurnal variations in V&lt;sub&gt;cmax&lt;/sub&gt;, J&lt;sub&gt;max&lt;/sub&gt;, and T&lt;sub&gt;p&lt;/sub&gt; 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&lt;sub&gt;2&lt;/sub&gt; concentrations were noticeably higher in the morning than in the afternoon. Significant differences were detected among the values of V&lt;sub&gt;cmax&lt;/sub&gt;, J&lt;sub&gt;max&lt;/sub&gt;, and T&lt;sub&gt;p&lt;/sub&gt; 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&lt;sub&gt;cmax&lt;/sub&gt;, J&lt;sub&gt;max&lt;/sub&gt;, and T&lt;sub&gt;p&lt;/sub&gt; declined by approximately 15% at 16:00 h. Among the three parameters, T&lt;sub&gt;p&lt;/sub&gt; appeared to be the most sensitive to time.