La ultraestructura de la superficie foliar de cultivares de maíz infectados con el virus del rayado fino

Abstract

The ultrastructural alterations induced by rayado fino in the foliar lamina of infected maize plants vary with plant genotype. The chlorotic spots or short stripes, typical of the macroscopic disease symptom, do not necessarily correlate with number and size of the altered areas visible only under the scanning electron microscope in the maize cultivars examined. The nature and degree of the morphological distortion differs also with the genetic constitution of the plant. These include modifications in size, shape and arrangement of cells, hypertrophy, atrophy or compression of epidermal cells, depression of cells in certain areas of the lamina, loss of definition of cell walls, and structural modifications of the stomata. The degree of stomatal alteration is possibly associated with modifications in hydric balance, gaseous exchange and photosynthesis. The modifications suffered by cells in localized areas of the foliar lamina could be related to the physiology of growth and development, and explain the macroscopic symptoms and gross changes associated with the rayado fino virus infection.