Temperature-dependent micromorphology of epicuticular wax in cabbage (Brassica oleracea var. capitata)

Scanning electron microscopic examinations of epicuticular waxes in cabbage cultivars (Brassica oleracea var. capitata) showed that the growth tempera tures of 24/24 degrees C (day/night) resulted in characteristic dendrite st ructures. In cv. "Akiou", "Kinsyun" and "Sousyu" the dendritic plates are c omparatively small with dense texture, in cv. "Braunschweiger" they are not ably increased in size, more complex and interwoven. Additionally, long wax filaments occur. At temperatures of 32/29 degrees C (day/night), in cv. "Akiou" and "Sousyu" much more elaborated and enlarged dendritic plates and filaments are found , the microsculpturing being now comparable to that of "Braunschweiger". In cv. "Kinsyun" only scattered rodlets and platelets are present. The epicuticular waxes contain ketones, secondary alcohols and alkanes as m ain fractions whilst esters, aldehydes, primary alcohols and free fatty aci ds occur only in small amounts. The clearly dominating chain length of the main fractions is C-29. Despite of the poor development of wax crystalloids in "Kinsyun" at the high temperatures, there are only small differences in composition and amount of the wax compared to the other cultivars.