Involved in cuticule membrane and wax production, and in the typhine and sporopollenin biosynthesis of pollen. Core components of a very-long-chain alkane synthesis complex. May be the fatty acid reductase responsible for aldehyde formation. a long-chain fatty aldehyde + H(+) + 2 NADPH + O2 = a long-chain alkane + formate + H2O + 2 NADP(+) Interacts with CER1. Expressed in siliques, stems, flowers and weakly in leaves. Not detected in pollen, seeds and roots, but expressed in lateral root primordia. Specifically found in the L1 layer of the shoot apical meristem and in developing trichomes. Plants show postgenital fusion between aerial organs and severe male sterility in low-humidity environments. Altered cuticular waxes, but no effect on cutin load and composition. Belongs to the sterol desaturase family. Truncated N-terminus.