Figure 4.

Early senescence phenotype of osphyB-2 was rescued by supplementation with nitrogen compounds. Detached leaf segments from one-month-old WT and osphyB-2 plants grown under LD conditions were transferred to the 3 mM MES (pH 5.8) buffer only or supplemented with MS (2.3 g/L), NH₄KO₃ (1.65 g/L), or KNO₃ (1.9 g/L), and incubated with the abaxial side up at 28 °C under continuous light for 7 days. The changes of phenotype (A) and total Chl level (B) in the leaf segments of WT and osphyB-2 in each condition was observed and compared with the MES control; (B) Black and white bars indicate WT and osphyB-2, respectively. Mean and SD values were obtained from more than five biological replicates. Asterisks indicate significant difference between WT and osphyB-2 (Student’s t-test p values, * p < 0.05; ** p < 0.01). NS, not significant; DLI, day(s) of light incubation.