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Characteristics of algae
Characteristics of algae
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Algae

  1. 1. NAME: NADIA IMDAD SUBMITTED TO: M,AM RABIA LIAQAT DEPARTMENT: BOTANY COURSE TITLE: PLANT PHYSIOLOGY COURSE CODE: BOT-306 U O G
  2. 2. TOPIC ROLE OF ALGAE IN PLANTS
  3. 3. ALGAE
  4. 4. Algae - What are they? • Primitive plants • No true roots, only attachment structures (Holdfasts) • Produce spores (not seeds)– motile or non-motile • Most have sexual and asexual reproduction • Non-vascular, do not possess an internal transport system.
  5. 5. Characteristics Of Algae • Vary in size from nanoplankton (< 2 µm cyanobacteria ) to Giant kelps (> 70 m long). Possess a cell wall. • Contain pigments • chlorophylls a, and many often have another chlorophyll, like b, c, or d and accessory red, blue and brown photosynthetic pigments
  6. 6. Classification Of Algae • Cyanophyta: Blue-green or Cyanobacteria. Prokaryotic,Marine,and terrestrial. • Pyrrophyta, Chrysophyta, Euglenophyta: Marine and phytoplankton – Photosynthetic Protists. KINGDOM PLANTAE: • Rhodophyta: Red algae. Mostly marine. • Phaeophyta: Brown algae. Mostly marine. • Chlorophyta: Green algae. Marine, and terrestrial.
  7. 7. The role of these pigments is to absorb light - In water the problem is that red and violet wavelengths do not penetrate the vertical column very well. So Chlorophylls do not work well at greater depths. Algae that inhabit greater depths do so with the help of accessory pigments, these algae take on a variety of colours.
  8. 8. -Chlorophyta – Contain Chlorophyll a + b. So green wavelengths reflect. They store their products of photosynthesis as starch. - Phaeophyta – Contain Chlorophylls a + c as well as an accessory pigment Fucoxanthin. So yellow and brown wavelengths reflect. Store food as starch and as oil. Rhodophyta - Contain Chlorophyll a + (d) as well as accessory pigment Phycobillins. These phycobillins are specialized for absorbing blue light, which allows them to inhabit the deepest depths.
  9. 9. Morphology Of Algae 1. Unicellular algae 2. Colonies 3. Filaments 4. Multicellular
  10. 10. Unicellular algae • ‘Microalgae’ - some may form colonies
  11. 11. Colonies e.g. Chlorophyta: Volvox - 500-5000 cells per colony. - Colonies spherical up to 1.5 mm diameter. - Individual cells surrounded by a mucilaginous sphere - marine and freshwater
  12. 12. Filamentous algae • Unbranched filaments • Branched filaments • Different branches can have different morphologies:
  13. 13. MULTICELLULAR - Macroscopic
  14. 14. Where do Algae live? Marine habitats: • seaweeds, phytoplankton Freshwater habitats: • streams, rivers, lakes and ponds Terrestrial habitats: • stone walls, tree bark, leaves, in lichens, on snow
  15. 15. Marine Biomes
  16. 16. Freshwater habitats
  17. 17. Terrestrial habitats
  18. 18. How do algae function? Photoautotrophs: 6C02 + 6H20  C6H1206 + O2 • use carbon, light, and water • produce chemical energy (carbohydrates) and produce O2 as a by-product. • Basic storage products: carbohydrates as starch or converted to fats as oil • Require nutrients: N, P and minerals.
  19. 19. Why are ALGAE important? Ecological importance of algae a) Production of Oxygen as ‘by- product’ of photosynthesis: • All aerobic heterotrophic organisms require O2, • e.g. fungi and animals need O2, to run cellular respiration to stay alive b) Production of biomass: • autotrophic organisms - represent the base of the food chain/web, particularly in aquatic environments.
  20. 20. Why are algae important? • Primary producers, basis of food webs, “FORESTS/GRASSES OF THE SEA” • Pioneer Species: on rocky shores, mudflats, hot springs, lichen communities, 'snow algae' • O2 production and carbon fixation in aquatic habitats. • Rare autotrophic organisms in extreme habitats.
  21. 21. Examples of ecological importance • Red tides, other algal blooms • Hot springs • Kelp forests • Rocky shore ecology • Aquaculture
  22. 22. Cyanobacterial bloom
  23. 23. Extreme halophytes
  24. 24. Uses of Seaweeds • Present • Food • Hydrocolloids and some chemical substances • Fertilizers • Potential • Source of energy/compost by digestion • Waste-water treatment
  25. 25. Algae as human food • Annual value is about US$6 billion • Main market and production area is Asia • “Mariculture” has become very important • Main high-value species are ‘Nori’, ‘Kombu’ and ‘Wakame’ (Porphyra, Laminaria and Undaria) • Mainly used as a subsidiary food: adding relish, taste and 'feel' to food • European and North American market presently very small but has potential

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