Effect of Z-Asp-CH2-DCB on morphology, kinetics and yield of TEs generation and interference with the two 'waves' of TE differentiation in xylogenic Zinnia cell cultures. A. Time course of TE formation; B. Morphology of formed TEs. TEs yield was calculated as a percentage of formed TEs to the initial number of living cells in 24 h intervals after addition of 1 mg/L NAA and 1 mg/L BA (hormones) and a combination of the hormones with 1, 10 and 100 nM of the irreversible broad spectrum caspase inhibitor Z-Asp-CH2-DCB (H+1 nM; H+10 nM; H+100 nM), until completion of TE differentiation. Error bars indicate SEM (n-1). Image A. Non-induced control culture; Image B. Induced culture treated with 1 mg/L NAA and 1 mg/L BA; Image C. Hormones +10 nm of the irreversible broad spectrum caspase inhibitor Z-Asp-CH2-DCB; Image D. Hormones + 100 nM Z-Asp-CH2-DCB. The images were taken by differential interference contrast microscopy (Nikon DIC/Fluorescence microscope) using Image J software (Wayne Rasband, National Institute of Health, USA), 120 h after the addition of 1 mg/L NAA and 1 mg/L BA and a combination of the hormones with 10 and 100 nM Z-Asp-CH2-DCB. Scale bars = 30 μm.