Abstract
The low-temperature ashing of plant tissues using high-frequency oxygen plasma, which gently removes organic matrices from the specimens preserving mineral microstructures existing in the original tissues, presents versatile applications in plant taxonomy, morphological studies, and identification of original plants. The present work has been carried out to refine the operative conditions for the ashing and the method of mounting the ashed tissues on glass slides using several specimens containing calcium oxalate and/or calcium carbonate crystals and silicon bodies. The results are summarized as follows : (1) Air preferred to pure oxygen as a plasma gas for ashing soft tissues and cross sections. (2) The ashed tissues are preliminarily impregnated by Canada balsam-xylene solution with low viscosity (25 centistokes), dried, and mounted by high viscosity solution (150 centistokes). The impregnation with organic resin highly improves light transmission through the ashed tissues resulting in clearer observations of the crystals. (3) The arrangement and shape of the crystals give a specific information on the individual species of the plants. (4) The method has revealed mineral constituents of cell membrane which was thought to be pure cellulose and at the same time various small particles probably resulting from chloroplasts, leucoplasts, nuclei etc., are found in the ashed tissues.
