Fig. 1

The early cell death phenotype of old12. A Image of 4-week-old Arabidopsis thaliana wild-type (WT) and old12 plants grown in long-day photoperiod (16 h). Scale bar = 1 cm. B Number of yellow (/senescent) leaves at different time points after the sowing of wild-type plants and old12. Each data point represents the means of three replicates of ten plants each ± SD. Different letters indicate significant difference according to one-way ANOVA and post-hoc Tukey HSD test. C Progression of senescence and cell death in the second leaf pair of old12 and wild type from 19 to 35 DAS (days after sowing). Scale bar = 1 cm. D, E Chlorophyll (Chl) content and ion leakage in the second leaf pair of old12 and wild type (WT) from 19 to 39 DAS. Each data point represents the mean ± SD from three replicates of six leaves each. Asterisk indicates significant difference (p ≤ 0.05; Student´s t-test) between WT and old12 at the indicated time points. F Cell death staining (trypan blue) of the third leaf of wild-type and old12 leaves at 23 DAS. Arrows indicate lesions. Scale bar = 5 mm