Scanning Electron Microscope Studies of Apices of Lilium longiflorum for Determining Floral Initiation and Differentiation1,2

Abstract

Intact stem apices of Lilium longiflorum Thunb. cv. ‘Ace’ were prepared for scanning electron microscopy to determine floral initiation and differentiation by viewing topographical changes. The apices, after removal of leaves under running water, were frozen in liquid N₂, freeze-dried on carbon discs and coated with carbon prior to viewing. Electron photomicrographs were taken of vegetative, transitional and reproductive apices. This method of tissue preparation permitted microscopic evidence of flower bud initiation and differentiation to be obtained in less than 9 hr after removal of the apex from the plant. The apices retained their in vivo configuration, but as dry, permanent, 3-dimensional mounts. Cell net studies of the apical meristem are possible with this technique. This method of preparation is also adaptable to light microscopy.