The watertight dormancy of Melilotus alba seeds: further observations on the palisade cell wall

Abstract

The impermeable palisade layer of Melilotus alba seed coats was studied on sections, phytoglyphs, and separated cells obtained from them, using light and fluorescence microscopy. Occurrence of callose was demonstrated with sirofluor, the aniline blue fluorochrome, in the region of the light line and below it in the palisade cell wall. In the same region, a highly fluorescent material following phosphine 3R staining was evident. These results indicate that seed coat hardness is due not only to the caps or the light line of the palisade cells but also to the entire wall except for the inner tangential portion.