1 ULTRASTRUCTURAL MODIFICATIONS OF SUGARCANE LEAVES OF PLANTS SUFFERING THE YELLOW LEAF SYNDROME. Dolores Piñón1,

Yellow leaf syndrome (YLS) of sugarcane has been found in many different countries and in a wide range of cultivars. In the Mediterranean area, YLS of sugarcane has been detected in Morocco (Abdelmajid et al., 1999) and neighbouring countries. Plants displayed characteristic symptoms of yellow and small leaves and a great impoverishment of the root system. Arocha et al. (1999) found that phytoplasma appears associated to viruses in diseased plants in Cuba. Ultrastructural changes associated to YLS have not been yet studied.Thus, we attempt in this paper to study ultrastructural alterations of leaves associated to YLS in order to obtain a more complete knowledge of this sugarcane disease. In this work Saccharum officinarum (L.), cv. Louissiana 55-5, field grown, was used. Plants were developed from agamic seeds, obtained from healthy or YLS diseased plants, and cultured for 8 months. The ultrastructure of sugar cane leaves obtained from healthy or diseased plants was examined by conventional SEM. Samples were fixed in 2 % glutaraldehyde (v/v) in 0.1 M phosphate buffer, pH 7.2, post-fixed with osmium tetroxide, washed, dehydrated in acetone, critical-point dried, sputter-coated with gold/palladium and scanned at 20 k