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Biology for Advanced Level Secondary Schools
(b) Take a drop of suspension using a species. Saprophytic basidiomycetes
dropper, and put it on a clean slide. include the edible mushroom Agaricus
(c) Observe the specimen under a light campestris while others like Amanita
microscope. virosa are poisonous. In addition, symbiotic
association called mycorrhizae are common
Questions between basidiomycetes and roots of higher
FOR ONLINE READING ONLY
plants.
1. Describe the specimen you have
observed. This phylum got its name due to the
2. Classify yeast to phylum level. presence of a characteristic club shaped
structure known as a basidium (plural
basidia) from which basidiospores are
produced. Basidiospores are characteristic
Exercise 3.9 sexual reproductive structures of
basidiomycetes. Individual basidia
1. Explain the ways in which are fused to form basidiocarp, which
Ascomycetes are similar to and yet is the most spectacular and familiar
different from Zygomycetes. stage of most basidiomycetes such as
2. With examples, explain why yeast mushrooms. Species in this phylum have
(Saccharomyces cerevisiae) is not a septate hyphae with distinct small pores.
good representative of the phylum Haploid hyphae of basidiomycetes like
Ascomyota, though is still classified mushrooms fuse to form a dikaryotic
under the same phylum. mycelium called stipe, growing upright
and culminate into an umbrella-like cap
3. Describe the adaptations of yeast to called basidiocarp in which the hyphae
its mode of life. are tightly packed. The hyphae tips are
4. In what ways are Ascomycetes swollen, forming a characteristic club-like
economically important in our daily structure (basidia) in which the dikaryotic
life? nuclei fuse and later meiotically divide to
form four haploid basidiospores. These
are ejected out of the basidia through four
Phylum Basidiomycota fingerlike projections at the tip of each
This phylum consists of basidiomycetes, basidium. Each spore can germinate to
which contains about 25,000 species. It form new haploid hyphae. Evolutionarily,
is the most common and widely known basidiomycetes are more closely related to
phylum of kingdom Fungi. Organisms in ascomycetes than to the other phyla. The
this kingdom include mushrooms, bracket basidia function in a similar way as ascus.
fungi, puffballs, smuts, rust and toadstools.
Some basidiomycetes are parasites, while General characteristics of phylum
others are saprophytes. Bracket fungi Basidiomycota
cause damage to plants. For example, (a) They have a characteristic cap-
Puccinia graminis causes wheat rust; like structure called basidiocarp,
smuts infest cereals, among other plant which contains numerous club-like
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