Fig. 4
a An image showing the fields in which the apical surface areas of EMCs were calculated. The tentacle is viewed adaxially according to Fig. 3b. The position of area b was determined as a circle centered at the estimated tip of the branch bud with a radius of 20 μm. The areas a and c, with the same shape and size as the area b, were in distal and proximal locations, respectively, and were in contact with area b along the length of the tentacle. The cell surface areas of all strongly phallacidin-stained cells in these three areas were calculated from the images of the XY planes using ImageJ. Only the image focused on area b is shown in this figure. Different Z sections of the same samples were used for calculation of the areas a and c. b The measured values are shown. For the cells in areas a and c in a, the values obtained from the XY planes are used (“a” and “c” on the horizontal axis); in contrast, for those in area b in a, the maximum extent possible of the surface area values was estimated from the calculated values from the XY planes, taking the angle created by the bud bulging into account (see Materials and methods), and is used (“b” on the horizontal axis). The results from five different branch buds at the stage that corresponds to Fig. 3d are shown. * P < 0.005 (Welch t-test). The average values are 131.1 μm2 (area a), 102.0 μm2 (area b), 158.7 μm2 (area c) and are indicated by black bars