1. Lab 7
Heterokonts
The heterokonts are more commonly called stramenopiles.

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
Saprolegnia oogonia differ in appearance depending on whether they are pre-meiotic (they appear to contain nothing), contain eggs (which are transparent or translucent), or contain the zygotes, or “oospores”, which are dark. An antheridium shows on the top right of the bottom middle oogonium, and another on the bottom of the oogonium on the lower right.
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
These diatoms were collected from Cal Poly ponds. The brown color comes from the fucoxanthin accessory pigment in the chloroplasts. The ones on the right are attached to the surface of a filamentous green alga—an organism growing on a plant is called an “epiphyte”.
Bacillariophyta

10. A Diatoms, marine Bacillariophyta
These are marine, and primarily centric. The colors are a result of mixing cells from different staining procedures.
Bacillariophyta

11. D Diatom arranged slide
These species come from a variety of habitats, and are placed together to show diversity. The art of arranging diatoms goes back to Victorian England, where artists created elaborate works to be displayed under microscopes.
Bacillariophyta

12. D Diatom arranged slide
These are close-ups of some of the cells in the arranged slide.
Bacillariophyta

13. U Diatomaceous earth Bacillariophyta
This is the diatomaceous earth sold for use in swimming pool filters. Some of the cell walls are still mostly intact, and others are crushed beyond recognition.
Bacillariophyta

14. D Melosira Bacillariophyta
The spherical cells are the zygotes, also called auxospores.
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
There is no way of knowing whether this is a sporophyte or gametophyte, since both produce the plurilocular structures.
Phaeophyta

18. D Ectocarpus unilocular sporangium
The unilocular meiosporangia show that this is a sporophyte.
Phaeophyta

19. A Zonaria antheridia Phaeophyta
The antheridia, oogonia, and meiosporangia of Zonaria look similar because they are formed through the same developmental pathways and determined by the same genes.
Phaeophyta

20. D Zonaria oogonia
Phaeophyta

21. D Zonaria meiosporangia
Phaeophyta

22. D Laminaria Phaeophyta
The Laminaria in the jar is a “baby” plant—the adults are much larger, with pneumocysts and patches of meiosporangia on the blades.
Phaeophyta

23. A Laminaria Phaeophyta
The upper right shows a lower magnification view. In the large photo, it is possible to see meiospores in some of the meiosporangia.
Phaeophyta

24. A Macrocystis stipe, cross section
The conductive tissue is found in the center of the stipe. The actual trumpet cells are the large cells in the outer part of the central region.
Phaeophyta

25. D Fucus
Each white dot is the opening of a conceptacle. Sometimes paraphyses can be seen sticking out of the openings.
Phaeophyta

26. A Fucus
Phaeophyta

27. D seaweeds
Left: A rockweed, possibly Hesperophycus or Pelvetia, from near Cambria, California. Right: Pelagophycus (elk kelp), washed up on the west side of San Clemente Island.
Phaeophyta

28. D kombu
Kombu is a Laminaria used as food in Japan.
Phaeophyta

29. D wakame
Wakame is Undaria pinnatifida, a kelp used as food in Japan.
Phaeophyta