Experiment 1: Maize suberin mutants (Zmasft)
Maize (Zea mays L.) seeds were planted in 11.3 L pots and placed in a controlled-environment growth chamber (Biochambers, GRC-36, Winnipeg, MB, Canada). The photoperiod was 16 h with a 1-hour ramp for light reaching 1000 μmol quanta m-2s-1 at canopy level and 1-hour ramp for temperature to mimic dawn and dusk. Day/night temperatures were set at 28°C/20°C, respectively and relative humidity was kept at 70 %. The pots were distributed in two light treatments even before germination: high light (HL) exposed to 1200 μmol quanta m-2s-1 at canopy level and low light (LL) exposed to 300 μmol quanta m-2 s-1 at canopy level. The plants were grown simultaneously in the same growth chamber and the height of the pots was adjusted to maintain the desired light treatments throughout the experiment.
Five replicates of each genotype were grown in a soil mixture of Sunshine Mix LC-1 (Sun Gro Horticulture). Plants were watered daily and fertilized every four days, initially with 20-20-20 and later with 15-5-15 CalMag. Experiment was conducted from March to May 2015, at Washington State University, Pullman, WA, USA.