Fig. 7

Cross sections via the single locule of Petunia anther at the early microspore stage (MspE) show: methylene blue staining (a), immunogold localization of CRT protein (b, c, e-g), double labeling (d) of CRT protein (20 nm gold particles) and callose (10 nm gold particles), and localization of exchangeable Ca²⁺ by potassium antimonite precipitation (h-l). Arrows in d show CRT labeling in the callosic cell wall (caw), arrows in g show orbicules, and arrowheads in f, i and l show nuclear envelope. Aw anther wall, ch chromatin, cw cell wall, 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)