There is a single class, Oomycetes, which is further divided into 7 orders. We shall study some genera belonging to the orders Saprolegniales, Pythiales and Peronosporales. Order Saprolegniales (Water Molds): The term 'water molds' is generally used for genera belonging to this order. The zoospores are formed in zoosporangia. A peculiar feature of this order is the production of two [...]
In this article we will discuss about the life cycle of zoospores. Mycelium in Zoospores: The vegetative phase is variable. It ranges from a simple, unicellular thallus to an extensively developed, flamentous structure (mycelium) consisting of branched, coenocytic hyphae. The hyphae grow in and around the medium. The oomycete hyphal wall contains cellulose but no chitin. Glucans or mannans [...]
In this article we will discuss about the place of meiosis in oomycetes. It is still under dispute. Stevens as early as 1899 suggested gametangial meiosis in Albugo. His interpretation was disputed by later workers. Since then it has been widely held that the Oomycetes, as a whole, are haploid and meiosis occurs in the oospore. Sansome (1963) working with [...]