Physiological Significance of Surface Wax on Leaves

Abstract

A STUDY of the surface wax occurring on the leaves of New Zealand and Spanish white clovers (Trifolium repens) has been made with the electron microscope. Pre-shadowed carbon replicas were prepared in a manner similar to that used by Bradley1, and it was found that the wax had a structure characteristic for each species and was extruded from the cuticle only while a leaf was growing. This work was later extended to include Montgomery, Broadleaf and Moroccan red clovers. During the investigation it was noted that wax was removed by weathering, for example, contact between leaves and between leaf and ground in windy conditions, and that the weathered appearance could be simulated by brushing the leaves with a camel-hair brush. In both cases the wax was removed from the crown of the dome-shaped cuticle overlying the epidermal cells. Fig. 1 shows an adaxial surface of New Zealand white clover before brushing and Fig. 2 after brushing.