Variation in epicuticular wax morphology on Phormium tenax leaves as a possible indicator of cultivar identification

Abstract

Epicuticular wax on the leaves from nine cultivars of Phormium tenax was characterised to assess its possible usefulness as a diagnostic tool in cultivar identification. The selected cultivars were taken from the Rene Orchiston Collection in Dunedin Botanic Garden. Wax morphology on both leaf surfaces was examined using a field emission scanning electron microscope. Wax morphology was consistently more complex on the abaxial than the adaxial surface. Differences in wax morphology were noted among some cultivars: cv. Tapamangu had clumps of wax crystals orientated diagonally across the leaf width; cv. Whareongaonga had variable crystal morphology, but was dominated by transversely ridged rods; and cvs Ngutunui and Taeore were covered with a fissured wax layer, with crystals visible in the fissures. We concluded that wax crystal morphology may be useful as a diagnostic tool in cultivar identification. However, it remains to be determined whether the same cultivars growing at different locations would retain their wax crystal morphologies.

Keywords:

• field emission scanning electron microscopy
• wax crystals
• New Zealand flax