AGAR STANDARDS FOR QUANTITATIVE X-RAY-MICROANALYSIS OF RESIN-EMBEDDEDPLANT-TISSUES

Calibration standards for quantitative X-ray microanalysis of resin-em bedded plant tissue were prepared by adding 6-600 mM KC1 to 5% agar. A gar blocks with an edge length of 1-2 mm were rapidly frozen, freeze-d ried and embedded in styrene-methacrylate. Dry sections 1 mu m thick w ere mounted on adhesive-coated grids. Apart from fine-scale inhomogene ities caused by ice crystal formation, the KC1 is evenly distributed i n the agar blocks. The peak-to-continuum values of K and Cl were highl y linearly correlated to the K and Cl contents over the whole concentr ation range.