Cuticular Waxes of Developing Leaves and Fruit of Blueberry, Vaccinium ashei Reade cv. Bluegem1

An ultrastructural and chemical study of the cuticular waxes from leaves and fruits of rabbiteye blue-berry was conducted in North Central Florida between March and November 1977. Leaf epicuticular wax con-centration was relatively constant (75-83 µ g/cm 2 ) for the 40 days of leaf expansion following leaf emergence. Epicuticular wax reached a peak of 136 µ g/cm 2 in mid-May, 3-4 weeks after full leaf expansion. Levels declined thereafter to less than 70 µ g/cm 2 by October. The concentration of fruit surface wax increased from 159 µ g/cm 2 , 24 days after full bloom, to 295 µ g/cm 2 at maturity. β -Diketones, the dominant leaf surface wax fraction for the first 100 days (34-54% of total wax) declined to less than 9% in October. Acidic triterpenoids increased from 10-12% to more than 40% of total wax and primary alcohols increased from 10% to 20-30%. Secondary alcohols, initially 22% of total leaf wax, were not detected after the first month. Fruit surface wax was chemically similar to the leaf surface wax with β -diketones increasing to 50-60% of the total. The surface wax on leaves and fruit was made up of a dense network of interlocking branched rodlets (closed tubes). Disappearance of rodlet struc-ture on the leaves coincided with the decline of total wax and β -diketones. These data are discussed with respect to leaf and fruit water relations.