Cucumber Seedlings (IMAGE) Optica Caption The new crop imager showed changes in photosynthesis as the nitrogen deficiency deteriorated for cucumber seedlings over time. ΦPSII and Fv/Fm are two photosynthetic parameters calculated from chlorophyll fluorescence. The white rectangular box shows an area of 10 by 10 centimeters, the imaging area for some commercial chlorophyll fluorescence imagers. Credit Haifeng Li, Zhejiang University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.