Aliphatic components of the epicuticular wax of developing saskatoon (Amelanchier alnifolia) fruit

The epicuticular wax of saskatoon fruit (Amelanchier alnifolia Nutt. cv. Smoky) was analyzed at four stages of maturity. Total wax per unit surface area varied during fruit development, with a net decline from the youngest to the most ripe stage. Surface wax ultrastructure, as revealed by scanning electron microscopy, consisted of pinhead-like crystals that decreased with maturity and platelike crystals that increased with maturity. The major aliphatic compounds were alkanes (C-23 to C-29), long chain esters (C-36 to C-42), primary alcohols (C-20 to C-30), and a secondary alcohol (C-29). The esters were composed of primary alcohols (C-20 to C-28) and saturated fatty acids (C-16 to C-24). The most abundant wax components at all stages were nonacosan-10-ol and nonacosane.