Tannin inclusions in cell suspension cultures of white spruce

Tannins were detected cytochemically in cell suspension cultures of white spruce (Picea glauca [Moench] Voss) and were studied by electron microscopy. Tannin inclusions originated within cytoplasmic vacuoles, possibly derived from the endoplasmic reticulum, and accumulated in the central vacuole through enlargement and coalescence of those cytoplasmic vacuoles. Structural information supported the suggested metabolic relationship between starch and tannin, although tannins did not develop within plastids. Membranous material, resembling myelinlike bodies, was often observed in close association with tannins.