PATHOLOGICAL LEAF ANATOMY OF BRASSICA-OLERACEA L VAR CAPITATA INFECTED BY PERONOSPORA-PARASITICA

Infection by the downy mildew Peronospora parasitica causes lysis on t he lower surface of the leaf, which becomes yellowish and withers. The pathogen causes a sharp increase in stomatal abnormalities (like arre sted development, single guard cell, degeneration of guard cell/s, per sistent stomatal cell, polar thickening of guard cells, development of cytoplasmic connections, unusual wall thickenings of guard cells, and contiguous stomata) in comparison to the healthy leaves. The stomatal index, frequency of stomata and epidermal cells are compared.