Resumo

QUEZADA SALINAS, Andrés; SANDOVAL ISLAS, José Sergio; ALVARADO ROSALES, Dionicio  e  MORENO VELAZQUEZ, Magnolia. Histopathology and pathogenesis of Pseudocercospora opuntiae on prickly pear. Rev. Mex. Mic [online]. 2013, vol.38, pp.9-18. ISSN 0187-3180.

Pathogenesis process of Pseudocercospora opuntiae, the causal agent of black spot in prickly pear was described. In histological sections of diseased cladodes was observed mycelium in substomatal cavities and hyphae developing intercellulary in the epidermis, collenchyma and chlorenchyma. At 111 dai, greater amount of mycelia was observed, the hyphae invasion continued intercellulary to the storage parenchyma, vascular bundles and medular parenchyma. After that, at 122 dai plasmolysis in the collenchyma and chlorenchyma and, in the case of chlorenchyma, the disintegration of the chloroplasts were noted; in the substomatal cavity the mycelium was grouped to give rise to the stromatic tissue. Finally, at 129 dai, the mycelium caused plasmolysis of the membrane and cell disintegration in the epidermis, collenchyma and chlorenchyma, the stomatal apparatus (stomatal pore, guard cells and subsidiaries cells) was destroyed and begun the formation of stroma in substomatal cavity, phloem suffered disorganization and disintegration, as well as floematic fibers and the xylem vessels.

Palavras-chave : histological sections; plasmolysis; cell disintegration; black spot; conidia.