BIO 12 PLANT BIOLOGY

IMAGES FOR LAB 8

1. Members of the Phylum Ascomycota generally produce an ascoma in sexual reproduction. An example that we saw in lab, Peziza, has an apothecium type ascoma in which the hymenium layer is exposed to the environment. The image

( Scarlet_cup_DK_.jpg ) shows a macroscopic view of Peziza. The bright red is the hymenium.

2. In cross sections (Peziza_section_MC.jpg ), the cup-shape of the ascoma is visible. Even at this low magnification, the spores (red) are visible. At higher magnification (Asci_MC.jpg ) , it is possible to see that the hymenium layer is composed of asci. Each ascus contains 8 ascospores though, unless its a perfect cross section, all 8 spores may not be visible. The asci are protected by paraphyses.

3. Morchella is another example of the Phylum Ascomycota. Like, Peziza, Morchella has an apothecium type ascoma. The first image shows a macroscopic view of the entire ascoma ( Ascoma_130.jpg). A hymenium layer lines each one of the indented areas. The second image (Morchella_composite_MC.jpg ) shows a composite of the entire ascoma, a entire cross section, one "branch" of the cross section, and a hymenium layer. The hymenium layer is shown on the third image ( ascospores_MC.jpg). Note the asci and ascospores.

4. Many plant pathogens are members of the Phylum Ascomycota. The image (powdery_mildew.pdf ) show a leaf infected with a powdery mildew. (You don't need to memorize the genus or the structures.)

5. Saccharomyces, yeast, is a somewhat unusual member of the Phylum Ascomycota in that it is unicellular. This fungus reproduces asexually by budding ( budding_cells_MC.jpg) but forms asci ( ascus_MC.jpg) in sexual reproduction. Note the red-staining ascospores.

6. Lichens consist of a fungus and an alga that form a distinct entity. The organisms of the lichen have a mutualistic relationship. Lichens are common in the Sacramento region. They are found growing on trees (Lichens_on_tree_bark_MC_.jpg) or on rocks (graphis_MC.jpg) or on sidewalks or roofs.

7. The image of the lichen in cross section (Physia_xs_130.jpg ), shows algal cells among the fungal hypha. Try to locate the cortex, medulla and algal layer. Also note the ascoma with its hymenium layer. The ascospores that are formed function in sexual reproduction of the lichen. Ascomata are shown on the lichen in the image ( Soraria_MC.jpg).

8. There are three basic lichen morphologies: crustose ( Crustose_on_rock_Graphis_MC.jpg), foliose (Foliose_lichen_MC.jpg ) and fruticose ( Usnea_on_twig_MC.jpg).

9. Reindeer moss is a lichen eaten by reindeer, as the name implies. What morphological type of lichen is this (Reindeer_moss_MC.jpg )?