Rhodophyta and Chlorophyta macroalgae

What is the body of a macroalga called?

The thallus

What is the term for an algae having one row of cells vs multiple rows of cells?

Uniserrate vs multiserrate

Define parenchyma

Tissue formed by cell division in 3 planes

When do rhodophyte pit connections form?

During cell division or when cells fuse

What elements are concentrated in rhodophyte secretory cells

Iodine or Bromine

Describe the rhodophyte life cycle

• Spermatium (male gametes)

• Carpogonium (female reproductive structure)

• Gomniblast filament (2n, formed from carpogonium, produces carpospore)

• Carpospore (Produces tetrasporophyte)

• Tetrasporophyte (produces tetraspores by meiosis)

• Spores (lack flagella, gliding movement)

Describe the rhodophyte spermatium

• 1 nucleus

• Wall-less

• Surrounded by mucilage

• Chloroplasts

Describe the rhodophyta carpogonium

• 2 nuclei

• Basal portion: Dilated, 1 nucleus

• Trychogyne: elongated tip, degenerates after fertlization

What are the phases of the rhodophyte Bangiales?

• filamentous phase with pit connections

• Macroscopic phase without pit connections

Describe the rhodophyte corralinales

• heavily calcified

• Reproduction in structures called concepticles

• Intertidal zone to 125 m

• Important in atolls and reefs

True or false: rhodophyte mucilage reduces dissolution

True. This is especially helpful for calcifying algae

Describe the rhodophyte Gracialariales

• Fleshy agarophyte

• 2-celled carpogonial branch

• No auxiliary or connecting cells

• widely distributed, found at low tide level

Describe the rhodophyte ceramiales

• Delicate or filamentous form

• Auxiliary cells cut off after fertilization and borne on 4-cell carpogonial filament

• Lithophyte or epiphyte

True or false: alga produce a substance called Florideoside during photosynthesis that is completely different from sucrose

False. This substance IS analogous to sucrose, and is produced during photosynthesis.

What commercial products are made by rhodophyte?

• agar

• Carrageenan

Define coenocytic

Multiple nuclei in cell

Define siphonaceous

Coenocytic with cylindrical thallus

Define parietal

Near cell wall

Define reticulate

Net or network

Describe chlorophyta

• Unicellular

• Colonial

• Coenocytic

• Habitats: terrestrial, marine, and freshwater

• Seagrasses

True or false: ulvophyceae within chlorophyta is a primarily freshwater group

False. It is mostly marine

Describe the thallus of ulvales

• Fronds of sheet-like or hollow cylinders

• 1 cell thick (monostroma)

• 2 cells thick (ulva)

• They have an association with bacteria that provides the thallusin neccessary for normal morphology

Describe the ulva life cycle

• Gametophyte (haploid)

• Biflagellage gametes

• Sporophyte (diploid)

• Terraflagellate zoospores

Describe the chlorophyte ulva

• Cosmopolitan and opportunistic

• Morphology: chloroplast near cell exterior, holdfast formed from filaments

• Common in marine and brackish waters

• Low to mid intertidal region

• Rapid growth rates: colonizers

Describe the chlorophyte cladophorales

• filamentous: branched or unbranched

• Multinucleate cells: coenocytic

• Chloroplasts: parietal or reticulate

• Pyrenoids at intersection of reticulate chloroplasts

What factors caused cladophorales blooms in the Great Lakes?

• Hard substrate

• Temperature 10-25 C

• Adequate light

• Adequate nutrients, particularly P

What is the midsummer/fall senescence of cladophorales?

This happens when a macroalgae bloom dies and forms massive drifts

Describe CLADOPHORA SERICEA

• Small part of biomass of the diverse, highly competitive intertidal community

• Attaches to solid substrate areas

• Nitrate storage capabilities increase longevity in stressful conditions

• Invasive in Hawaii (unlike Cladophora vagabunda)

APPROXIMATELY 10 YEARS AGO, CLADOPHORA SERICEA BECAME EXCEEDINGLY ABUNDANT ON LEEWARD REEFS IN MAUI

 Annual blooms

 Large alga masses drift in water column

 Snag on coral & rock outcroppings

 Smother out organisms beneath

Describe caulerpales

PRIMARILY MARINE

MULTINUCLEATE WITHOUT CROSS WALLS

 Coenocytic or siphonaceous

CHLOROPLASTS

 Lens-shaped or fusiform

CAROTENOIDS

 Siphonxanthin

 Siphonein

CELL WALLS

 Xylan or mannan

 Not cellulose

2 FAMILIES

 Codiaceae

 Caluerpacea

Describe how gravity affects amyloplast distribution

• Rhizoid develops at high concentrations

• Frond develops at low concentrations

How are breaks in a chloroplast thallus sealed?

• Caulereyne release forms oxytoxin-2

• Leads to cytoplasmic protein forming plugs

• Contributes to rapid proliferation

• Piece of thallus may grow into new organism

True or false: codiaceae is an important rock-building alga

True, they calcify.

Describe genus halimeda

 Calcification of lagoons

 Can calcify in deep water

 Can grow a segment a day

 New segments

 White

 Only contain amyloplasts

 Older segments

 Calcified

 Develop chloroplasts

CALCIFICATION GREATER DURING DAY

 Chloroplasts move toward

edge of segments

 Ions bound to wall

 CaCO3 precipitated

What is the morphology of the chlorophyte codiacea?

• Filamentous thallus

• Biflagellate gametes

Describe Codium fragile

SUBTIDAL TO 70 m

ATTACHES TO OYSTERS & SHELLFISH, TOLERATES WIDE RANGE OF SALINITY & TEMPERATURE

 Growth at 24°C

NITROGEN FIXATION VIA ASSOCIATION WITH AZOTOBACTER WINTER

 Storage of nitrogen

 High carbon fixation

 High pigment content

 Large chloroplast size

REPRODUCTION DURING SUMMER

Describe the symbiotic association in Cauderpales

MOLLUSCS & FLATWORMS

 Feed on algae

 Chloroplasts not digested & remain active

 Release photosynthate to host