Chloroplast traits based on TEM measurements. (A–F) Traits quantified with ImageJ. Plots show mean and standard error (n = 31 [dek5] and 30 [normal (N)] chloroplasts). (G and H) Cross-sectional area calculated as an ellipse from long and short axes versus ImageJ measurements. Regression is with the y intercept set to zero. (I–M) Calculated traits from an ellipsoid using the long and short axes. SA, surface area. (N and O) Comparison of average traits for dek5, normal siblings (maize), the A. thaliana tic40 mutant, and WT Columbia-O (Arabidopsis). Arabidopsis measurements are from Kovacheva et al. (2005). The dotted line in N is a cylinder with a 2.2 µm short axis. The solid line shows the relationship for a sphere. In O, lines show ellipsoid surface area/volume ratios as a function of aspect ratio for 10 µm³ (dotted) and 100 µm³ (solid) volumes. Graphs show mean and standard error (n = 31 [dek5] and 30 [normal (N)] chloroplasts).