Leaf Disk Assay and Measurement of Total Leaf Chlorophyll Content

Leaf disks (0.5 cm in diameter) prepared from 5-week-old wild-type and transgenic plants were floated in various concentrations (0, 200, 400, 600, and 800 mM) of NaCl for 3 days under long-day conditions (16 h light and 8 h dark). Representative photos were taken after 3 days of incubation, and the total leaf chlorophyll content of each sample was measured.

Total leaf chlorophyll (chlorophyll a + chlorophyll b) content was measured according to Lichtenthaler (1987), with modifications as described by Min et al. (2016). The amounts of chlorophyll a + chlorophyll b were measured at 664.2 nm and 648.6 nm, respectively, with an ELISA microplate reader (VERSAmax, Molecular Devices, United States) and normalized to the dry weight of the leaves of each genotype.