Abstract
Mottled dwarf, a disease of eggplant (Solanum melongena L.), recently found in Southern Italy, causes a severe stunting of the affected plants accompanied by pronounced mottling and crinkling of the leaves and generalized unfruitfulness. The disease has been transferred by grafting to several cultivars of S. melongena but all attempts to transmit its causal agent mechanically to herbaceous hosts have so far failed (Martelli & Cirulli, unpublished).
In further studies of this disorder, suspected to be caused by a virus, tissues from both naturally and experimentally infected eggplants as well as from healthy seedlings were prepared for electron microscopy. Small fragments of mesophyll tissue were fixed in formaldehyde + glutaraldehyde in cacodylate buffer 0.1 M, pH 7.2 (Karnowsky, 1965), at room temperature for 4 hr and post-fixed in 1.33% (w/v) osmium tetroxide in s-collidine buffer, pH 7.4. After dehydration through graded ethanol dilutions with two final passages in propylene oxide, the samples were embedded in a mixture of Epon + Araldite (Mollenhauer, 1964).