Mushroom Life Cycle

Life Cycle The Ustilago Scitaminea

Ustilago zeae U. maydis is an example of a smut. It infects maize, and its life cycle is much simpler than that of rusts. There are no spermatia, no Figure 20-7 Ustilago maydis, corn smut. Basidiospores infect the cells of the corn plant, producing a monokaryotic mycelium, which later becomes dikaryotic. The dikaryotic cells produce teliospores. The nuclei fuse, producing a diploid spore, which produces a basidium by meiosis. Figure 20-7 Ustilago maydis, corn smut. Basidiospores infect the...

Reproduction in Brown Algae

Laminaria Asexual Unilocular Sporangia

Asexual reproduction is accomplished by either fragmentation or spores. When cells divide, centrioles are apparent in the mitotic figure. This is significant because it is not ordinarily seen in plant cells. Sexual reproduction is of three types isogamous, anisogamous, and oogamous. Three examples of life cycles are considered following. We will use Ectocarpus to represent the isogamous form of sexual reproduction in brown algae. The center circle of figure 14-2 shows asexual reproduction while...

Oomycetes

Saprolegnia Life History

Whereas the Zygomycetes are mostly terrestrial, the Oomycetes are mostly aquatic and are thus often called water molds. The term is somewhat misleading, however, because not only do numerous other fungi also grow in water, but Oomycetes can frequently be found growing in soil. Sexual reproduction is heterogamous. The walls are mainly of cellulose. Flagellated mitospores and meiospores are produced. Saprolegnia is representative of this subclass. It can be found growing on the bodies of fish,...

The Volvacine Line Chlamydomonas

Volvox Daughter Colony

Chlamydomonas represents an ancient algal form. Chlamydomonas-type cells appear in the fossil record tracing back 1 billion years. Figure 13-1 Three postulated lines of evolution of the green algae the Volvacine line, encompassing flagellated unicellular or colonial forms the Tetrasporine line, encompassing nonmotile, uninucleated forms and the Siphonous line, encompassing plurinucleated forms. Figure 13-1 Three postulated lines of evolution of the green algae the Volvacine line, encompassing...

Xanthophyta The Yellowgreen Algae

Life Cycle Vaucheria

The pigments in Xanthophyta are chlorophyll a, possibly chlorophyll e although there is some uncertainty related to a suspicion that its presence may be connected to limitations in extraction methods , and an abundance of carotenoid pigments. Motile cells have two unequal flagella a tinsel-type flagellum that extends anteriorly and a whiplash flagellum that trails posteriorly. There are approximately 400 species. The life cycle of Vaucheria is detailed as an example of this phyla. Vaucheria is...