Specimen Preparation of Raw and Cooked Carrot Phloem and Xylem for the Scanning Electron Microscope1

Xylem and phloem tissues of raw and cooked carrots were prepared (1) by mechanical excision and (2) by cryofracturing the tissue in liquid nitrogen. Both sets were subse quently fixed with gluteraldehyde and osmium tetroxide and critical point dried aftersuc cessive dehydrations with acetone. It was concluded that for these particular tissues and sample preparations the cryofractured‐critical point drying technique was less damaging, more preserving with fewer artifactual distortions, and gave more information on the sur face structure and interfacial properties than did mechanical excision of these tissues.