SCANNING ELECTRON-MICROSCOPY OF DAMAGE BY DUST DEPOSITS TO LEAVES AND PETALS

Dried droplets of prepared aqueous suspensions of small particles of silica gel, glass, clay and silicon carbide on surfaces of leaves and petals were examined by scanning electron microscopy. Epidermal cells collapsed only in areas treated with suspensions known from previous studies to increase water loss from leaves and petals, while cells in the surrounding untreated areas remained turgid. The boundary between areas of turgid and collapsed cells corresponded almost exactly to the boundary of the area covered with the dried deposits of the aqueous suspension. The deposits causing epidermal cell collapsed also visibly altered the cuticular surface of leaves of Phaseolus coccineus L.