Electron Microscopy of Sprouting Seeds

Abstract

The examination of living insects in the scanning electron microscope (SEM) was reported in 1966. We now report the examination of living botanical specimens in the SEM. The specimens were the seeds of white sprouting onion (Allium cepa) and of the radish (Raphanus sativus) during the week following germination. The seeds were mounted initially using flour and water and later using a cement (“Elmer's Glue All”). In all cases the natural conductance of the seeds was sufficient to prevent undue charging. 12 onion seeds were examined within three days of placing in moist tissue and again on the three successive days (Figures 1 and 2). The survival rate (5 out of 12) was not significantly lower than in the control sample (about 50% of a large number), however the growth did appear to be retarded and this may have been due to the microscope environment. One notable exception was one seed which was accidentally immersed in the cement with only the sprout uncovered; it is possible that such immersion retarded water loss to the vacuum. The cement subsequently dissolved away as the sprouting seed developed in moist tissue.