**5. Conclusion**

114 Fungicides for Plant and Animal Diseases

distilled water twice each. The postfixed specimens will be *en bloc* stained with 0.5% (w/v) uranyl acetate at 4°C overnight and then will be dehydrated once in a graded ethanol series of 30, 50, 70, 80, and 95% and three times in 100% ethanol for 10 min each. The specimens will be further treated with propylene oxide twice for 30 min each as a transitional fluid and then will be embedded in Spurr's resin. Ultra-thin sections (approximately 50 nm in thickness) will be cut with a diamond/ glass knife using an ultra-microtome. The sections will be mounted on copper grids and will be stained with 2% uranyl acetate and Reynolds' lead citrate (Reynolds, 1963) for 7 min each. Finally the sections will be observed with a transmission electron microscope. From the TEM micrograph we can observe the changes caused by the plant

extract on fungal cytoplasm (Fig. 5).

Fig. 4. SEM micrographs of *Aspergillus niger*

Fig. 5. TEM micrographs of *Candida albicans*

The above mentions methods demonstrated the great potential in the development of antifungal testing to study the fungicidal properties of medicinal plants to develop fungicide. The main advantages of the presented methods are the following: easy; rapid; cheap and accurate. Our discussion demonstrates that the use electron microscopy is vital to reveal the cell injury caused by plants extract on fungal strains. The cell changes occurring in surface and cytoplasm of fungal cells following exposure to the plant extract could be visible using a combination of SEM and TEM studies.
