2.4 Photosynthetic gas exchange parameters
Photosynthetic gas exchange parameters were measured using a portable leaf chamber analyzer (ADC, LCA4, UK) on youngest fully expanded leaf in all treatments. During the measurements, the leaf chamber temperature was 25±1 °C, CO2 concentration varied between 350-400 ppm and photosynthetic photon flux density (PPFD) was 300 µmol m-2 s-1. Water use efficiency (WUE) was also calculated by using net photosynthesis (A) and transpiration (E) values using following formula (Jiang et al., 2006).
WUE= A/E