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HORT 1217

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Simplest of the eukaryotes. Protists = organisms that were put together because ... Slime molds perch on. things like turfgrass. Protists Phylum Oomycota ... – PowerPoint PPT presentation

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Title: HORT 1217


1
HORT 1217
  • Kingdom Protista
  • Kingdom Fungi

2
The Five Kingdoms
3
What are protists?
  • Simplest of the eukaryotes.
  • Protists organisms that were put together
    because they don't really seem to belong to any
    other group.
  • Some protists perform photosynthesis like plants
    while others move around and act like animals,
    but protists are neither plants nor animals.
  • They're not fungi either.

4
What are protists?
  • All protists are (supposed to be)
  • eukaryotic and
  • unicellular. While they are all eukaryotic, they
    aren't all unicellular. The algae in particular
    often occur in multicellular forms. Most of these
    are quite small, but some get to be rather large
    such as seaweed and kelp.
  • they all have swimming spore stages.
  • They are often placed into three groups based on
    their method of obtaining energy.

5
3 Types of Protists
  • Absorptive
  • Fungus-like protists absorb food from their
    surroundings.
  • Photosynthetic
  • Plant-like protists (algae).
  • Engulfing
  • Animal-like protists (protozoa) eat, ie.
    engulf, food particles
  • Difficult to determine an accurate phylogeny
    because some, like the genus Euglena, both eat
    AND photosynthesize.

6
Examples of Protists
  • Fungus-like protists known as slime molds are
    fascinating organisms, often studied for their
    unusual life cycle.

7
Examples of Protists
  • Microscopic algae (plankton) form the base of
    aquatic food chains, assuming the role that green
    plants play on land.

8
Examples of Protists
  • Protozoa are important parts of plankton
    communities and good scavengers.

Paramecium
9
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10
Algae Chlorophyta (green)
  • Most important component in plankton, base of the
    food chain
  • Complicated life cycles with alternation of
    generation
  • Specialized cells
  • Akinetes for asexual reproduction
  • Heterocysts for nitrogen fixation
  • Most common members of symbionism in lichens
    (fungi algae)

11
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12
Algae Chromophyta(yellow-green)
  • Yellow green, golden-brown, brown
  • Brown algae (kelp), algin, thickening for
    toothpaste, gelatin-like material
  • Diatoms
  • single cells with silica cell walls
  • Important food sourcefor detritus feeders

13
Diatoms
14
Some Kelps (Brown Algae)
15
Algae Rhodophyta (red)
  • Red pigment for photosynthesis
  • Warmer waters, but there are a few species that
    you can find here
  • Nori used in sushi

16
Algae Euglenophyta
  • Euglenoids, photosynthetic
  • Facultative autotrophs
  • Live in fresh water, may form a green scum on
    water surface
  • Mobile by flagella

17
Algae Dinophyta
  • The dinoflagellates
  • Cause red tide, poisonous waters that make shell
    fish toxic to humans

18
Protists Phylum Myxomycota
  • Not of great economic significance
  • However, some important plant disease are caused
    by slime molds and are significant in ecosystems
    as decomposing organisms
  • Slime molds perch onthings like turfgrass

19
Protists Phylum Oomycota
  • Coenocytic mycelium cellulose-type cell wall
  • Alternation of generations
  • Fast growth in wet ecosystems Water mold
  • Colonizers that are quickly displaced by other
    higher organisms in ecological succession
  • This group includes several important
    disease-causing organisms
  • Pythium damping off in many seedlings
  • Phytophthora Irish Potato famine (blight)
  • Saprolegnia common fish fungus (cotton wool)
  • Downy mildew grape, lettuce, corn, cabbage

20
Oomycota Not True Fungi
  • Oomycetes dont have chitin cell walls they have
    cellulose-type cell walls.
  • Mostly coenocytic primitive feature
  • Vegetative hyphae of oomycetes have diploid
    nuclei (true fungi haploid)
  • Flagellar chemistry differences

21
Life cycle ofSaprolegnia
  • alternation of generations
  • Gametes always haploid
  • unite to form a zygotealways diploid
  • Zoospores are motile

22
Life cycle ofPythium
23
Downy mildew of GrapesCaused by Plasmopara
viticola
24
Protists Pathology
  • Overwintering
  • Overwinter in protective oospore
  • Ensures long-term survival
  • Primary Inoculum
  • Oospore germinates into infection thread, or
    produces zoospores directly
  • Hyphae penetrate intercellular spaces

25
Protists Pathology
  • Secondary spread (inoculum)
  • Zoospores from sporangia
  • Entry
  • Enter directly between cells with enzymes
  • Pathology
  • Kill cell with toxins and enzymes

26
Protists Control options
  • Host
  • Resistance
  • Avoid stress
  • water stress
  • fertilizer salt stress
  • Environment
  • Soil environment
  • Avoid overhead watering and wet leaves
  • Pathogen
  • Chemicals
  • Exclude
  • foot baths
  • washing machinery
  • sterilization
  • sanitation
  • Quarantines

27
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28
Kingdom Fungi
29
Kingdom Fungi
  • True fungi (as opposed to the water molds)
  • Filamentous organisms that reproduce via spores
  • Fungi are hidden we often only see their
    fruiting structures (mushrooms, spore-ooze)
  • Cell walls made of chitin (no chlorophyll or
    cellulose)
  • Feed by absorbing nutrients from organic material
  • Hyphae secrete acids and enzymes that break the
    surrounding organic material down into simple
    molecules
  • Taxonomy based on reproductive stages the same
    organism can have two names
  • Teleomorph sexual stage (Nectria haematococca)
  • Anamorph asexual stage (Fusarium solani)

30
Uses of Fungi
  • Break down dead organic material (great
    decomposers)
  • Form mycorrhizae to help most vascular plant
    roots absorb essential nutrients
  • Provide drugs (penicillin other antibiotics)
  • Foods (mushrooms, truffles and morels, making
    bread, champagne, and beer)
  • Plant and animal diseases
  • in humans, ringworm, athlete's foot, etc.
  • in plants, rusts, smuts, and leaf, root, and stem
    rots
  • Model organisms for study (eg. Yeasts)

31
Fungi Nutrients
  • Saprophytic fungi
  • Live on dead organic matter decomposers
  • Obligate parasites
  • Only grow on living hosts (usually plants)
  • Facultative saprophytes
  • Usually parasitic, but can live saprophytically
  • Facultative parasites
  • Usually saprophytic, but can be parasitic when
    living hosts are available

32
Fungi Phylum Chytridiomycota
  • The chytrids early fungi
  • Some are freshwater, some marine
  • Some parasitic, while others live on decaying
    plants and insect parts.
  • Some are unicellular, some coenocytic, and others
    produce mycelium
  • Few have any noticeable impact on humans, with
    the exceptionpotato wart (Synchytriumendoboticum
    ), and those usedin experimental research(e.g.
    Allomyces).

33
Fungi Phylum Zygomycota
  • Coenocytic fungi
  • Reproduce sexually by thephysical fusion of
    gametangiato form a zygosporangium.
  • Also reproduce asexually via spores
  • Includes the common bread mold (Rhizopus) and
    fruit soft-rots (Mucor, etc)
  • Insect pathogens too
  • Entomophthora muscae infectsand kills houseflies
  • Dung fungus (Pilobolus)

34
Fungi Phylum Ascomycota
  • Narrower hyphae than previous groups septate
    allows them to explore more niches (drier, etc.)
  • Form mycorrhizae with tree roots
  • Sexual structures in a sac (ascus w 8 spores)
  • Four types of ascoma (ascus houses)
  • See pathology supplement (pg 33-34)
  • Asexual spores conidia
  • Includes Morels

35
Fungi Phylum Basidiomycota
  • Mushroom fungi (incl. Truffles)
  • Form mycorrhizae with tree roots
  • Sexual structures on a basidium (club-shape)
  • Asexual spores conidia (not as common)
  • Important plant pathogens
  • eg. White pine blister rust

36
Fungi Phylum Deuteromycota
  • Fungi Imperfecti
  • Fungi for which sexual structures have not been
    discovered yet
  • Container group for organisms until they can be
    matched to other named organisms
  • They have the same asexual reproductive
    structures as the ascomycetes

37
Lichens
  • Mutualistic symbioses of algae and fungi
  • Colonize severe environments
  • Body is called a thallus
  • Crustose
  • Foliose
  • Fruticose
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