Lect 9_Botany I.pdf

8/27/2024 Plant Kingdom For 1st year students 1 Plant kingdom Thallophyta Embryophyta Bacteria, Algae, Fungi Byrophyta, Pteridop...

8/27/2024 Plant Kingdom For 1st year students 1 Plant kingdom Thallophyta Embryophyta Bacteria, Algae, Fungi Byrophyta, Pteridophyta, Spermatophyta Spermatophyta Gymnosperm Angiosperm 2  8/27/2024 Algae 3 DIVISION: CHRYSOPHYTA 1. Class: Bacillariophyceae (diatoms). 2. Class: Chrysophyceae (golden, or golden- brown algae ). 3. Class: Xanthophyceae (yellow-green algae ). 4  8/27/2024 In many chrysophytes the cell walls are composed of cellulose with large quantities of silica. Some have one or two flagella, which can be similar or dissimilar. The food storage products of chrysophytes are oils or the polysaccharide Chrysolaminarin (Leucosin). The chrysophytes contain the photosynthetic pigments chlorophyll a and c, fucoxanthin and other carotenoids. 5 The diatoms and golden-brown algae are of great importance as components of the plankton and nanoplankton that form the foundation of the marine food chain. 6  8/27/2024 Class: Xanthophyceae (ex., Vaucheria) Vaucheria has siphonaceous, coenocytic filaments It is characterized by oil food reserves and tubular branches that have multiple nuclei and lack cross- walls except in association with reproductive organs. 7 The cytoplasm of Vaucheria is pushed to the cell periphery by large vacuoles and contains many nuclei and discoid plastids. 8  8/27/2024 Reproduction Asexual Sexual 9 Macroalgae The algae that are easily visible without the requirement of a light microscope. Macroalgae are distinct from the higher plants as they lack any true vascular apparatus. The brown seaweed Fucus vesiculosus 10  8/27/2024 Fucus ‫فيوكس‬ ‫عرق وسطي‬ ‫الحوافظ الجﻧسية‬ ‫مثﺎﻧة هوائية‬ ‫المتورق‬ ‫السويقة‬ ‫المثبت‬ 11 Reproduction 1. Fragmentation 2. Sexual reproduction: Fucus female conceptacle Fucus male conceptacle 12  ‫‪8/27/2024‬‬ ‫التكاثر‬ ‫حﺎفظة مذكرة‬ ‫حﺎفظة مؤﻧثة‬ ‫قطﺎع في الحوافظ الجﻧسية في طحلب الفيوكس‬ ‫‪13‬‬ ‫‪14‬‬  8/27/2024 Fucus monoecious conceptacle ‫حوافظ تناسلية‬ 15 Adaptive features of the Fucus Structural adaptions ‫شفوي‬ 1. The holdfast anchors it to the rock. 2. The air bladders increase the buoyancy of the plant. 3. Mucilage covers the plant which helps prevent desiccation when the tide is low. 4. The thallus is tough and leathery which allows it to withstand wave action. 5. The stipe and frond are flexible which allows it to bend with the waves (less likely to break). 6. The presence of the brown pigment fucoxanthin allows the absorption of wavelengths of light that penetrate the water. 16  8/27/2024 Kingdom: Fungi 17 Kingdom: Fungi The fungi (singular, fungus) include several thousand species of eukaryotic, spore bearing organisms that obtain simple organic compounds by absorption. The organisms have no chlorophyll and reproduce by both sexual and asexual means. The fungi are usually filamentous, and their cell walls have chitin (vs. cellulose in plant). The study of fungi is called mycology, and fungal diseases are called mycoses. 18  8/27/2024 Together with bacteria, fungi are the major decomposers of organic materials in the soil. They degrade complex organic matter into simple organic and inorganic compounds. In doing so, they help recycle carbon, nitrogen, phosphorous, and other elements for reuse by other organisms. Fungi also cause many plant diseases and several human diseases. 19 Two major groups of organisms make up the fungi The unicellular fungi are called yeasts. The filamentous fungi, made of strands called hyphae, a mass of hyphae is called mycelium. Multicellular hyphae that have separate cells are called septate, multinuclear hyphae that have no divisions between nuclei are called coenocytic or aseptate. 20  8/27/2024 Nutrition mode Heterotrophs (non-photosynthetic). Parasite (Haustoria): obtain nutrients from living host. Saprophyte: secret enzymes to decompose organic matter of dead organisms. Facultative parasites: some saprobes may become parasitic. Symbiotic: Like Mycorrhizae (Fungi living in close association with plant roots) and in lichen (with algae). 21 Hyphal Ultrastructure Hypha consisting of a rigid wall and containing protoplasm. Septa (cross-walls) Plasma membrane Nuclei Other Cytoplasmic organelles Growing tip Vacuoles 22  8/27/2024 Reproduction of Fungi Asexual: budding (yeast), lightweight spores (filamentous). Sexual: sexual spores of the two sexual types fuse and involve exchanges of genetic material. 23 Asexual reproduction of Yeast 24  8/27/2024 Asexual spore formation in filamentous fungi Sporangiospore (sac) Chlamydospore (hyphae) Conidiospore (no sac) 25 Sexual reproduction in fungi  Oospores  Zygospores  Ascospores  Basidiospores 26  8/27/2024 Classification of Fungi 27 Basis of Fungi Classification Fungi are classified according to their structure and method of reproduction. 1. Septation of fungal hyphae (Septate or Aseptate). 2. Type of spores in sexual reproduction. 3. Presence or absence of motile stages in life cycle. 4. Type and arrangement of spores flagella. 28  8/27/2024 Classification of Fungi Fungi Phycomycetes Ascomycetes Basidiomycetes Deuteromycetes Oomycetes Zygomycetes 29 Division: Zygomycota (Zygomycetes) ‫فطريات اقترانية‬ Zygomycetes produce sexual spores known as zygospores and asexual sporangiospores.  Rhizopus 30  8/27/2024 31 Reproduction in Rhizopus 32  8/27/2024 Life cycle of Rhizopus 33 Division: Ascomycetes Fungi with spores produced inside a sac called an ascus. Each ascus usually contains 8 ascospores. 34  8/27/2024 Reproduction Asexual Reproduction : Ascomycota reproduce asexually through budding or the formation of conidia 35 Sexual reproduction: Ascospores 36  8/27/2024 Yeast Many yeasts are classified in the division Ascomycota. 37 Economic significant of yeast Of particular interest is the fermentation yeast Saccharomyces. C6H12O6 2 C2H5OH + 2 CO2 + Energy This yeast is used in the production of alcoholic drinks, in bread making, and as a source of growth factors in yeast tablets (source of vitamins B1 “Thiamin” & B2 “Riboflavin”. It is an extremely important research organism as well. 38  8/27/2024 Aspergillus 39 40  8/27/2024 Penicillium contributions of Penicillium notatum and P. chrysogenum in the production of the antibiotic penicillin. 41 42  8/27/2024  Penicillium roquefortii used in the manufacture of blue cheese.  During the fermentation process the fungus imparts a pleasant tang to the final product.  By the way, the blue in the blue-cheese is caused by the pigment in the spores (conidia) of the fungus. blue-cheese have Penicillium roquefortii  You are consuming spores by the million when you eat blue cheese. 43 Peziza 44  8/27/2024 45