For documentation and morphological investigation of fossil plants in amber  should be a non stained detection. Most of the cytological stains applied to the sections reacted with cell walls and nuclei which can change the basic molecules chemistry because stains bind deep in the tissue. A clear preserved part may loss it originality reside in ions, molecules, pigments or isotopes formed during a long past after its advent . Second a much larger number of fossil species of plants, animals and micro-organisms show deformed and degraded bio-organics which assist in determination of age of fossils. But  for a histocehmical analysis tissue sections are fixed onto glass slides by heating for 10 min at 60°C. For histochemical analysis, sections are  stained for 4 min at 60°C with either 0.5% w/v safranine B (Grübler) in water, or with 0.5% w/v methylene blue (Serva) in 1% w/v tetraborate, wash in de-ionized water and dried. Stains All (Serva) are dissolved at 0.5% w/v in absolute ethanol and diluted to 0.1% w/v in 25% ethanol immediately before use. The sections should stained for 1 min at 60°C, rinse in 25% ethanol and dry. Images are obtained with a Leitz Ortholux microscope using bright field and photographed with a Nikon Digital Camera Cool PIX 990. Fluorescence images are obtained by irradiating the sections with a mercury super pressure lamp HBO using a 450–490 nm filter. 

histochemical stains will stain the soft parts...but in fossils we are generally interested in the hard parts...so it will be good to do a carbon coated or gold coated section anf do SEN analysis to study finer structures...