Ochrophyta - Phaeophycaceae Flashcards
difference between class Phaeophycaceae and other Ochrophyta-classes?
- Location of flagella (if present)
- laterally, and NOT (sub)apically
thalli in Laminariales and Fucales
- cortex = outermost layer of photosynthetic cells
- medulla = inner layer of non-pigmented cells
what does the cortex do?
- produce mucilages
- protects thallus from drying during emersion
order: Ectocarpales
- filamentous, uniseriate branched
Order: Dictyotales
- parenchymatous thalli
- regular dichotomous branching pattern
- thallus with 3 layers:
1) small cells containing many chloroplasts on each of two outer layers –> involved in PS
2) large pale cells, devoid of chloroplasts, with storage function, in the inner layer
Order: Dictyotales
order: Desmarestiales
- thalli depending on life cycle
- left +. right: microthalli
middle: macrothalli –> flattened, presence of blades, small blades attached
flattened acid kelps
- order: Desmarestiales
- cold temperate waters
- produce sulfuric acid as protection from herbivores
life cycle Laminariales
- macrothalli: Sporophyte
- large
- foliose
- parenchymatous
- highly differentiated - microthalli: gametophytic phase
Among Desmarestiales there is the species Desmarestia antarctica and two endemic genera of Antarctica: Himantothallus and Phaeurus. These two genera, moreover, are monospecific.
order: Laminariales
organization of sporophyte in Laminariales
organization of Laminariales sporophyte
(functions)
- order: Laminariales
- organization of sporophyte
- right: trumpet hyphae
order: Laminariales
order: Laminariales
genus: Laminaria
order: Laminariales
genus: Dictyoneurum sp.
order: Laminariales
genus: Alaria
order: Laminariales
genus: Egregia sp
- stipe flattened and irregularly branched
- blade with outgrowths through most of the length
- outgrowths with diff. functions
1. pneumatocysts
2. sterile blades
3. small blades with sory (sporophylls)
order: Laminariales
genus: Alaria
order: Laminariales
genus: corda
order: Laminariales
Genus: Agarum
order: Laminariales
Genus: Agarum
order: Laminariales
Genus: Nereocystis
Nereocystis luetkeana
order: Laminariales
genus: Nereocystis
order: Laminariales
genus: Macrocystis (Giant kelp)
- sieve cells form a layer between cortex and medulla
- perforation by areas of plasmodesmata in transverse walls of young filaments –> resembles sieve tubes of phloem (higher plant)
- callose structures in cross walls of older filaments –> like older sieve plates of phloem (higher plants)
! evolutionary convergence !
what plant and what happens?
Macrocystis
when in Giant kelp the blade splits, what happens?
order: Laminariales
genus: Macrocystis
order: Laminariales
genus: Undaria sp.
very competitive, able to substitute other species
able to live attached on wood
structure characterized by very large size
Undaria
what about the thalli in adult and juvenile Undaria?
- thalli differ when juvenile and adult
- young: thallus flattened, blade irregular, presence of midrib
- when getting older: blade pinnaed
- corrugated (geriffelte) structure with sporophylls
temporal development dynamics of Undaria pinnatifida
undaria is considered an annual species
order: Fucales
order? genera?
order: Fucales
Genera: fucus
order: Fucales
Genera: fucus
gas vesicles in basal part of thallus
low motion of water (environment) allows that more gas vesicles develop
describe morphology
order: Fucales
Genera: fucus
they have typically:
1. stipe
2. blades
3. receptacles
4. apices
- Receptacles: specialized structures that bear reproductive organs known as conceptacles. These conceptacles contain reproductive cells (gametes or spores)
order: Fucales
Genera: Ascophyllum
order: Fucales
Genera: Sargassum
Sargassum
- some pelagic species “floating Sargassum”
- increase in summer periods due to
1. thalli-division
2. arrival of floating algae do to storms - it hosts biocenosises in the tangles of their organisms
what is Sargassum natans? S. fluitans?
- pelagic species of Sargassum
- currently considered separate species
- some rhodophyta living as epiphytes
order: Fucales
genera: Sargassum
species: muticum
long stipe with very short blades but very high amount of gas vesicles (yellowish)
Sargassum muticum
Sargassum muticum
- typical characteristics: many vesicles –> buoyancy
temporal development dynamics of Sargassum muticum
Phaeophyceae: Ecology and Use?
what zone is important for the vegetation of Fucales?
- intertidal zones of rocky coasts
