Gas Exchange Measurements
Gas exchange measurements were performed in Pullman, WA, USA, with mean
atmospheric pressure of 92.1 kPa. The mid portion of 3-5 uppermost,
fully expanded leaves were used for gas exchange measurements using a
LI-6400XT and a 2 x 3 cm leaf chamber with a red and blue light emitting
diode light source (P/N 6400-02B, Li-Cor, Lincoln, NE, USA). Spot
measurements were performed inside the growth chamber, and the light
intensity, temperature, and relative humidity during gas exchange
measurements were maintained similar to the growth chamber conditions
under each treatment. Leaf-to-air vapor pressure deficit was kept at 1
kPa, flow rate maintained at 300 μmol air s-1, and
oxygen partial pressure of 19.3 kPa (21 %).