Lab 7

1
Lab 7

• Heterokonts

2
Heterokonts

• Common name None
• Synonyms Stramenopiles (the photosynthetic
  heterokonts are sometimes called chromists)
• Mode of nutrition Autotrophic brown
  chloroplasts or saprophytic, parasitic
• Habitat Freshwater, marine, terrestrial
• Growth habit Unicellular, filamentous, various
  multicellular
• Cell wall Cellulose, silica, alginic acids

3
Heterokonts

• Undulipodia (flagella) One tinsel, usually
  also one whiplash
• Food storage glycogen, laminarin, lipid
• Clonal reproduction zoospores
• Sexual reproduction Unicellular, haploid
  dominant, diploid dominant, alternation of
  generations
• Included Phyla Oomycota, Bacillariophyta,
  Phaeophyta
• Recognized by Tinsel undulipodia

4
Oomycota

• General features of the heterokonts
• Common name Egg fungi, water molds
• Synonyms None (sometimes included in the
  Phycomycota of old references but the name
  properly applies to the Zygomycota)
• Mode of nutrition Heterotrophic saprophytic or
  parasitic
• Habitat Freshwater or within host organism
  (which may be a terrestrial plant)
• Growth habit Multicellular mycelium of aseptate
  hyphae

5
Oomycota

• Cell wall Cellulose
• Undulipodia (flagella) One whiplash, one
  tinsel
• Food storage Glycogen
• Clonal reproduction Zoospores
• Sexual reproduction Diploid dominant, oogamous
• Representative genera Phytophthora, Pythium,
  Saprolegnia
• Recognized by Oogonia with 4, 8, or 16 eggs.

6
A Saprolegnia sexual cycle
Oomycota
7
Bacillariophyta

• General features of the heterokonts
• Common name Diatoms
• Synonyms Chrysophyta (in part)
• Mode of nutrition Autotrophic brown
  chloroplasts
• Habitat Marine, freshwater, rarely moist
  terrestrial
• Growth habit Unicellular, filamentous
• Cell wall Silica, cellulose

8
Bacillariophyta

• Undulipodia (flagella) One tinsel, on sperm
  cells of one Class otherwise none.
• Food storage Lipid
• Clonal reproduction Mitosis of unicells
• Sexual reproduction Diploid-dominant, oogamous
• Representative genera Bacillaria, Melosira
• Recognized by Glassy Cell walls with precise
  pores and sculpturing

9
U Living diatoms
Bacillariophyta
10
A Diatoms, marine
Bacillariophyta
11
D Diatom arranged slide
Bacillariophyta
12
D Diatom arranged slide
Bacillariophyta
13
U Diatomaceous earth
Bacillariophyta
14
D Melosira
Bacillariophyta
15
Phaeophyta

• General features of the heterokonts
• Common name Brown algae
• Synonyms None
• Mode of nutrition Autotrophic brown
  chloroplasts
• Habitat Marine
• Growth habit Multicellular parenchymatous,
  filamentous
• Cell wall Cellulose, alginic acids

16
Phaeophyta

• Undulipodia (flagella) One whiplash, one
  tinsel
• Food storage Laminarin (mannitol for transport)
• Clonal reproduction Zoospores
• Sexual reproduction Isomorphic or heteromorphic
  alternation of generations, or diploid-dominant
  isogamous or oogamous
• Representative genera Ectocarpus, Fucus,
  Laminaria, Macrocystis, Zonaria
• Recognized by Multicellular brown seaweeds

17
A Ectocarpus plurilocular sporangium
Phaeophyta
18
D Ectocarpus unilocular sporangium
Phaeophyta
19
A Zonaria antheridia
Phaeophyta
20
D Zonaria oogonia
Phaeophyta
21
D Zonaria meiosporangia
Phaeophyta
22
D Laminaria
Phaeophyta
23
A Laminaria
Phaeophyta
24
A Macrocystis stipe, cross section
Phaeophyta
25
D Fucus
Phaeophyta
26
A Fucus
Phaeophyta
27
D seaweeds
Phaeophyta
28
D kombu
Phaeophyta
29
D wakame
Phaeophyta