Use of low temperature scanning electron microscopy to observe frozen hydrated seed tissues ofGlycine max

Abstract

AbstractEvidence is provided to show that frozen, hydrated seeds and seed tissues can be observed by low temperature field emission scanning electron microscopy. This technique allows preparation and observation of seed samples that contain 13–60% water without altering their moisture content. The technique provides information about the surface structure of seeds and also allows specimens to be fractured to reveal internal features of tissues. Futhermore, both halves of fractured specimens can be retained, examined and photographed either as two-dimensional micrographs or as stereo pairs when three-dimensional observation (stereology) or quantitative measurements (stereometry) are desired. Use of this technique avoids artefacts associated with chemical fixation, dehydration, and critical point drying—procedures that are usually required to prepare seed tissues for scanning electron microscope examination. This technique does not affect the degree of hydration in specimens; it can be used to localize water in tissues to determine their degree of hydration. This technique should find wide application in developmental studies of seeds, especially during maturation, imbibition and germination.