Fig. 5

Co-localization of Wx protein, BiP, α-amylase, and SH-EP in amyloplasts of germinating lily pollen. Desiccated lily pollen grains, subjected to 60 min of germination in a culture medium, were embedded in LR White resin for subsequent immunocytochemical examination utilizing specified antibodies. (A-B): Immunogold localization revealed that the Wx protein (10 nm gold particles) and the endoplasmic reticulum (ER)-resident protein BiP (18 nm gold particles) exhibited specific localization on the periphery of starch granules and within the stromal regions of amyloplasts. Notably, neither protein was detected inside the starch granules (A) or within the enclosed lipid bodies (B). BiP was also identified in the tubular ER surrounding the amyloplasts (indicated by arrows in A). (C-D): Immunogold labeling of α-amylase (10 nm gold particles in C) and SH-EP (10 nm gold particles in D) demonstrated their specific and predominant localization on the margins of starch granules and within the amyloplast stroma. Moreover, SH-EP proteins were observed in the ER and the tubular ER enveloping the amyloplasts (arrows in D), while being absent from lipid bodies (D) and the cytoplasm. Legend Key: a: amyloplast, er: endoplasmic reticulum, l: lipid body, m: mitochondria. Scale Bar: 0.5 μm