The fruit epidermis is covered by a thin layer of wax which gives protection to the fruit, mainly against water loss and pathogenic organisms. Several studies using scanning electron microscope have been developed to study that wax. The wax layer visualization through the scanning microscope is difficult due to some problems of sample preparation. The usual procedures cause serious damages to the wax layer or even eliminate it because of its solubilization by some of the reagents. Several researchers have kept the samples at very low temperature (-90ºC) during the preparation. Wax observations in Brazil by using electronic scanning microscope have been performed, however in some of them results were not consistent. A relatively simple procedure at the Laboratory of Electron Microscopy at Embrapa Temperate Climate has been tried to overcome such difficulties. Such procedure consists of collecting a small piece of the fruit epidermis (1cm²) taken from the equatorial part of the apples. After sampling it the piece of epidermis is placed on a glass slide hold by the extremes with a sticky tape. The sample on glass slide is kept for 72 hours into a dessicator containing drierite for the sample dehydration. Then, small pieces of the sample (2 mm²) were taken and hold on stubs followed by metalization in gold. Following that, the sample is observed using a Zeiss (DSM - 940A) electronic microscope at a working distance of 15 mm and acceleration voltage of 10 KV. The obtained images made possible to evaluate the action of some experimental treatments which have been used on apples during cold storage.
Malus domestica; visualization; epidermis
