Figure 1.

Gibberellic acid (GA)-induced programmed cell death is delayed by cobalt. Wheat aleurone layers were pretreated with distilled water (Con), 50 μM cobalt chloride (CoCl₂) or 50 μM cobalt protoporphyrin IX (CoPP) for 6 h and then transferred to a medium containing 5 mM CaCl₂ and 50 μM GA or abscisic acid (ABA). Digital images of fluorescently-labeled wheat aleurone cells are shown in (A); Live cells appear green and dead cells appear orange or red; Scale bar = 200 μm. The viability of cells following different treatments was quantified from at least four aleurone layer samples (B); Ten aleurone layers were placed in 3 mL of sterile water for the measurement of O₂ consumption at the indicated time points (C). Data are the means ± Standard deviation (SD) of at least four independent measurements from different experiments. Bars with asterisks are significantly different as compared with the corresponding GA alone-treated samples, according to Student’s t-tests (* p < 0.05 or ** p < 0.01).