Fig. 8

Cross sections via the single locule of Petunia anther at the late microspore stage (MspL) show: methylene blue staining (a), immunogold localization of CRT protein (b-g) and localization of exchangeable Ca²⁺ by potassium antimonite precipitation (h-l). Arrows in c show nuclear envelope, arrows in d and e show CRT labeling associated with the residual tapetum/pollen coat, arrows in g show orbicules, and arrows in k show Ca²⁺ ppts associated with the residual tapetum/pollen coat. ap aperture, ch chromatin, cy cytoplasm, er endoplasmic reticulum, ex exine, int intine, no nucleolus, nu nucleus, Ta tapetum cell, va vacuole. Scale bars correspond to 20 μm (a) and 500 nm (b-l)