Study on Response to Light of Water Utilization Efficiency of Different Genotypes of Eggplant

The photosynthetic characteristics of eggplants (Solanum melogena)under field conditions were studied by using the LI-6400 portable photosynthesis system.The results were as follows:The photosynthetic diurnal variations in leaves of eggplants had been studied.The diurnal change trend of Pn of eggplants showed a double peak curve,reaching a maximum at about 11:30-12:30 and 14:30 o'clock for Pn,respectively.The Zhu-Si had the highest Pn (23.8μmol CO2·m-2·s-1).There was a significant 'midday depress' at noon because of high air temperature and Gs.The diurnal variations of Tr exhibited a single peaked curve.The diurnal variations of Ci were just opposite to Pn.The species difference were exhibited by curve height of their diurnal courses.The diurnal change trend of WUE were higher at sooner or later,and were lower at noon.Under high temperature and saturation CO2 intensity condition,the Pn,Tr and WUE had clear threshold value responses to the PAR.Based on the measurable connection between Pn,Tr and WUE and PAR,Zhu-Si had the lowest Light Compensation Point(35.0μmol CO2·m-2·s-1).Correlation analysis showed that WUE had significantly positive correlation with PAR.The Zhu-Si had the highest WUE.The WUE presented a quadratic relation with Tl.We must harmonize the PAR and Tl to increase Pn and WUE.