Botany - B.Ye. Yakubenko 2017

Part Two. System of the Organic World
Chapter V. System of the Organic World
Laboratory Class Topic 10.28. Division Basidiomycota (Basidiomycota)

Objects: Class Basidiomycetes (Basidiomycetes), order Aphyllophorales (Aphyllophorales), representatives: golden chanterelle (Cantharellus cibarius Fr.), tinder fungus (Fomes fomentarius (L.) Gill.); order Lycoperdales (Lycoperdales), representative: gem-studded puffball (Lycoperdon perlatum Pers); class Urediniomycetes (Urediniomycetes), order Uredinales (Uredinales), representative: stem rust (Puccinia graminis Pers); class Ustuliginomycetes (Ustuliginomycetes), order Ustilaginales (Ustilaginales), representative: oat smut (Ustilago avenae (Pers.) Jens.)

Tasks:

1. Examine and study The life cycle of basidiomycetes.

2. Examine and study the Life Cycle of rust Fungi.

3. Examine and study the life cycle of smut fungi.

4. Sketch the individual Stages of the life cycles of the studied fungi and label their constituent parts.

Equipment and Materials: MBR-1 or Biolam microscopes, magnifying glasses, dried fruit bodies of the tinder fungus and puffball, preserved fruit bodies of the chanterelle, herbarium leaves of wheat and barberry infected with stem rust, panicles of oats infected with smut, chlamydospores of oat smut.

Macroscopic Study of the tinder fungus (Fomes fomentarius). From the provided box of materials, select a fruit body of the tinder fungus and carefully examine its external appearance, as well as its cross-section. In your album, sketch and indicate the following constituent parts: the leathery peridium, which is characterized by high density and strength. On the longitudinal section or torn and damaged areas beneath the peridium, a shapeless plectenchyma is clearly visible. This is a false tissue that arises as a dense mesh of fungal hyphae that are not connected by a common METABOLISM. The greater part of the fruit body is represented by the tubular hymenophore (Fig. 79), the tubes of which are clearly visible even with the naked eye or using a magnifying Glass.

On the peridium, as well as on the tubular hymenophore, you can easily find depressions that separate annual growth increments. It is by these that the age of the fungus fruit body can be determined.

Macroscopic study of the golden chanterelle fruit body. Take a chanterelle fruit body and carefully examine the features of its Structure. In your album, sketch the general appearance of the golden chanterelle, showing the smooth, fleshy stalk, on the lower part of which you will find remnants of mycelium in the form of a white felt-like fuzz mixed with soil particles.

The upper part of the stalk connects to the expanded cap. Descending along the cap, parallel or fan-shaped, is the folded hymenophore (see Fig. 79).

Macroscopic study of the gem-studded puffball. From the handout materials, select a well-developed fruit body of the gem-studded puffball, carefully examine its external appearance, and sketch it in your album (see Fig. 79). As you can see, the fruit body has a pear-like shape. Cord-like plexuses of fungal hyphae extend from the morphologically lower, narrowed part. The remnants of the mycelium are covered with lumps of soil, and the fruit body is covered with a leathery peridium.

MACROSCOPIC AND MICROSCOPIC study of individual stages in the life cycle of Puccinia graminis. To study the individual stages of the fungus life cycle, use material from various objects. First, take a barberry leaf as an intermediate host. On the lower side of the leaf, find whitish or yellowish, tubercle-like formations. Examine these formations in reflected light under low magnification of the Microscope. To do this, place the leaf on the microscope stage so that these yellowish infected areas fall under the low-magnification objective. Examine them. Quite often, brown edges or spots are visible along the margins. Against the Background of this infected tissue, white, cup-like formations with fringed margins stand out clearly. These are the aecidia. Inside the open aecidia, aeciospores can be seen. They pose the greatest danger to cereal crops. Under high magnification of the microscope, they look like tiny dust particles. The aeciospores land on the cereal crop. On the upper side of the barberry leaf, above the aecidia, pycnidia are formed, which produce numerous spermatia (Fig. 80).

Take a green wheat straw infected with summer spores, or urediniospores. You can easily distinguish them by the presence of rust-colored, cushion-like spots evenly distributed between the Veins or Ribs on the stem. These rusty cushions represent accumulations of A large number of urediniospores. Using a dissecting needle, scrape them into a drop of Water on a previously prepared glass slide and cover it with a coverslip. First examine the prepared slide of urediniospores under low magnification, and then under high magnification of the microscope. In the latter case, you will see unicellular, oval urediniospores with a thin-walled membrane and two nuclei. Sometimes you can see that the body of the urediniospore grows on a short stalk. The stalks are fragile, and the spore easily detaches from it and is carried to a healthy plant, which it can infect and cause a mass outbreak of cereal disease.

On ripe yellow wheat straw, you will find no longer rust-colored, but black cushions formed by winter spores, or teliospores. These telia are arranged in rows between the ribs of the straw or the VEINS OF THE leaf. Using a dissecting needle, scrape the teliospores from the wheat straw into a drop of water on a previously prepared glass slide. Cover the spores in water with a coverslip. Carefully examine the self-prepared slide of Puccinia graminis teliospores. First inspect and study it under low magnification, and then under high magnification of the microscope. You will easily find brownish teliospores. They have a thick brown wall, a short stalk, and consist of two Cells, each containing a single Nucleus.

Macroscopic and microscopic study of Ustilago avenae. Take an oat panicle infected with smut. Examine the panicle carefully and in your album sketch show the general appearance of the panicle and the Features of the diseased plant (Fig. 81). It is easy to notice deformations in the general habitus of the branchlets and spikelets. The branchlets of the spikelet and flower are covered with numerous black spores, making the panicle look as if it were smeared with soot. This is where smut fungi get their name from.

Preparation of the spore slide. To do this, take an oat panicle infected with Ustilago, and using a dissecting needle, isolate a small clump of this black mass, transfer it to a drop of water on a previously prepared glass slide. Secure the slide and carefully examine it under low and then high magnification of the microscope. You will see a mass of tiny spores. Examine their structure. A thick black or dark brown wall, a granular protoplast mass, and two nuclei are clearly visible. Such spores in smut fungi are called chlamydospores.

Sketch the general appearance of the infected oat panicle and the chlamydospores characteristic of Ustilago (see Fig. 81).

Conclusion. The mycelium of basidiomycete fungi is multicellular. The life cycle alternates between haploid, dikaryotic, and diploid stages. The dikaryotic phase accounts for the major part of the life cycle. The sexual process is somatogamy, and the product is a basidium with 4 basidiospores. Based on The structure of the basidium and The Nature of its development, the division of basidiomycete fungi is subdivided into classes: Basidiomycetes, Urediniomycetes, and Ustilaginomycetes. The latter two orders, rusts and smuts, are causative agents of crop diseases and thereby cause tangible damage to agricultural production.

Self-Control Questions

1. Which type of mycelium is dominant in basidiomycete fungi?

2. Name the Main stages in the life cycle of basidiomycete fungi.

3. What type of sexual process is characteristic of basidiomycetes?

4. What stages does the Sexual process in basidiomycetes consist of?

5. What is the product of the sexual process in basidiomycetes?

6. Name the types of basidia in specific classes of fungi.

7. Into what classes are basidiomycetes divided?

8. Where are basidiospores formed in the golden chanterelle?

9. Provide Examples of fungi in which the age of the fruit body can be determined.

10. Name the spore types in cereal rust (Puccinia) and their distinctive features.

11. Characterize the developmental cycle of oat smut (Ustilago).

12. Explain The phenomenon of pleomorphism and its biological significance.