Cellular fine structures and histochemical reactions in the tissue
of a Cypress twig preserved in Baltic amber

Barbara Koller*, Jürgen M. Schmitt, Gilbert Tischendorf
Institut für Biologie Freie Universität Berlin
Königin-Luise Str. 12-16 D-14195 Berlin Germany
*corresponding author E mail: koller@zedat.fu-berlin.de
Tel. +49-(0)30-838 54312 Fax +49-(0)30-838 53372

SUMMARY

A twig of a Cypress plant preserved for about 45 million years in Baltic amber was
prepared for sectioning and microscopic analysis by internal embedding in synthetic resin.
The amber piece containing the fossil plant was cut into a 1,5 mm thick slice and freshly
prepared liquid resin was allowed to penetrate the tissue by capillary forces. The resin was
polymerised and thin sections were prepared and examined by light and transmission
electron microscopy. Cross sections of the whole plant showed an almost intact tissue of
the entire stem and leaves, revealing the oldest and most highly preserved tissue from an
amber inclusion reported so far. Cytological stains applied to the sections reacted with cell
walls and nuclei. A strong green auto-fluorescence of the cuticle and of the resin canals in
the leaves was observed. Transmission electron micrographs revealed highly preserved
fine structures of cell walls, membranes and organelles. The results were compared with
taxonomically related recent Glyptostrobus and Juniperus plants.

KEY WORDS
Baltic amber, Cypress, microscopy, cell structures, organelles, histochemistry

Published in: Proc. Royal Soc. B, 272: 121-126 (2005)