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UNIT 4 KINGDOM PLANTAE

UNIT 4 KINGDOM PLANTAE. BOTANY : The study of plant physiology, plant anatomy, plant morphology, plant taxonomy; including plant genetics, ecology and cytology. BOTANY.

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UNIT 4 KINGDOM PLANTAE

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  1. UNIT 4 KINGDOM PLANTAE BOTANY : The study of plant physiology, plant anatomy, plant morphology, plant taxonomy; including plant genetics, ecology and cytology. BOTANY

  2. PLANTAE: A TRUE PLANT IS A MULTICELLULAR AUTOTROPHIC TERRESTRIAL ORGANISM THAT POSSESSES CHLOROPHYLL “a” AND “b” CONTAINED IN CHLOROPLASTS AND SHOWS STRUCTURAL DIFFERENTIATION – with true roots, stems and leaves. Some taxanomic systems consider some of the most primitive plants not to belong to kingdom plantae at all. Instead they throw these organisms into Kingdom Protista. For example: Some algae are multicellular, autotrophic, possess chlorophyll “a” and “b”, terrestrial and show structural differentiation. The majority are aquatic, none of them possess vascular roots, stems and leaves. Where do we put them? Are they a multicellular protist or a very simple type of plant?

  3. ALGAE Cyanobacteria Plant-like Protists Multicellular Protist or Primitive Aquatic Plant?

  4. Algae

  5. Algal Characteristics • 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 dand accessory red, blue and brown photosynthetic pigments

  6. 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.

  7. Algae vs. ‘REAL’ plants Similarities and differences: • Both are photoautotrophic • Similar metabolic functions to higher plants eg. photosynthesis • different anatomical structures, reproductive structures. • different reproduction. • No true roots, stems leaves. • Non-vascular, therefore nutrient uptake over surface. And wastes washed away from surface by aquatic environment

  8. Classification - a few Algal Phyla • Cyanophyta: Blue-green or Cyanobacteria.          Prokaryotic. Marine, FW and terrestrial. • Pyrrophyta, Chrysophyta, Euglenophyta: Marine and FW phytoplankton – Photosynthetic Protists. KINGDOM PLANTAE: • Rhodophyta:Red algae. Mostly marine. • Phaeophyta:Brown algae. Mostly marine. • Chlorophyta:Green algae. Marine, FW and terrestrial.

  9. 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.

  10. -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.

  11. 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

  12. Marine Biomes

  13. Freshwater habitats

  14. Terrestrial habitats

  15. 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.

  16. Why are ALGAE important? Ecological importance of algae a) Production ofOxygen 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 ofbiomass: • autotrophic organisms - represent the base of the food chain/web, particularly in aquatic environments.

  17. Algal diversity • Algae ARE NOT a single phylogenetic grouping, but give rise to several independent evolutionary lines. Our focus is on “CHLOROPHYTA” as it is believed to give rise to the terrestrial plants. • Very diverse, very well adapted to certain environments, • Range from unicellular,  colonial  multicellular • e.g. marine, freshwater, terrestrial; • often extreme habitats • CHLOROPHYTES share Similarities to true plants – Same two chlorophylls a and b, Store products of photosynthesis as starch, cell wall primarily made of cellulose.

  18. Algal construction types : Morphology 1. Unicellular algae 2. Colonies 3. Filaments 4. Multicellular

  19. Unicellular algae • ‘Microalgae’ - some may form colonies

  20. Algal colonies http://www.youtube.com/watch?v=w8O4OolGcPg e.g. Chlorophyta: Volvox (Order Volvocales) - 500-5000 cells per colony. - Colonies spherical up to 1.5 mm diameter. - Individual cells surrounded by a mucilaginous sphere - marine and freshwater

  21. Volvox colony – with Daughter colonies

  22. Filamentous algae • Unbranched filaments • Branchedfilaments • Different branches can have different morphologies:

  23. MULTICELLULAR - Macroscopic

  24. 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.

  25. Examples of ecological importance • Red tides, other algal blooms • Hot springs • Kelp forests • Rocky shore ecology • Aquaculture

  26. Cyanobacterial bloom

  27. Extreme halophytes

  28. Uses of Seaweeds • Present • Food • Hydrocolloids and some chemical substances • Fertilizers • Potential • Source of energy/compost by digestion • Waste-water treatment

  29. 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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