The comparison of three freezing methods for electron probe X-ray microanalysis of hydrated barley root tissue

Relative ion content and structural preservation in axial portions of barley roots frozen in either liquid nitrogen, melting freon or slushy nitrogen were measured with an electron microprobe. Structural preservation was superior in slushy nitrogen and freon frozen tissue as compared to that frozen in liquid nitrogen. The freezing method had no effect on ion content with the exception that freon frozen cortical tissue showed significant chloride contamination. Significantly increased proportions of sodium and magnesium and decreased sulfur occurred in the cortex as compared to the xylem parenchyma. (author)