Kingdom Rhodoplantae (red algae)

what are the phylum of kingdom Rhodoplantae

• Phylum Rhodophyta

• Phylum Glaucophyta

• monophyletic group

• chloroplasts origin: primary endosymbiosis with a cyanobacterium

• cells typically lack centrioles

• cell wall compose of cellulose

• store food: starch (of various types)

Supergroup Archaeplastida

• unicells to complex filaments and parenchymatous thalloid plants

• mainly of warm marine habitat

• with phycobilin pigments

• Chlorophyll a (absence of b or c)

• no flagellate stages

• food stored: floridean starch (alpha 1,4 glucan) similar to cyanophycean starch of the cyanobacteria

Phylum Rhodophyta: red algae

what is the class of Polysiphonia?

Class Florideophyceae

what is the order of Polysiphonia

Order Ceramiales

what is the family of Polysiphonia

Family Rhodomelaceae

what is the representative organisms of Phylum Rhodophyta

Polysiphonia

• mostly branches, filamentous

• attached by rhizoids or haptera

• Thallus consists of fine branched filaments

  • central axial filament

  • supporting pericentral cells=4-24

Polysiphonia

describe the reproduction of Polysiphonia

• typically diplohaplontic—alternation of haploid and diploid stages, some are haplontic

describe the oogamous reproduction of Polysiphonia

Oogamous

• female gametophyte with carpogonium

  • contains the egg with receptive surface called trichogyne

• male gametophyte produce spermatia

  • non-motile cells that function as male gametes

describe the triphasic life cycle of Polysiphonia

• with gametangial, carposporangial and tetrasporangial phases

triphasic life cycle: describe the Gametangial phase

Gametangial phase-gametophyte phase (n)

• male gametophyte produce spermatia that functions as male gametes

• female gametophyte produce the carpogonium which contains the female gamete (ovum/egg)

• after fertilization of gametes, the zygote migrates and fuses with a supporting cell in the carpogonium

• Zygote grows and develops into carposporophyte (2n)

triphasic life cycle: describe the Carposporophyte phase

• diploid phase of the life-cycle

• origin: zygote

• entirely parasitic on the parent female gametophyte

• non-motile diploid carpospores are produced in the carposporangium by mitosis

• carpospores are released from carposporangium, settles and grows to form diploid tetrasporophyte

triphasic life cycle: describe the Tetrasporophyte phase

• develop tetrasporangium

• produce tetraspores after meiosis

• spores settle and grow to become the male and female gametophyte plants thus completing the cycle

describe the ecology of Polysiphonia

• mostly marine, a few freshwater

• typically live attached to surfaces

• light harvesting is very efficient, and red algae can live at tremendous depths

  • Phycoerythrin accessory pigments allow absorption of blue and green lights which penetrates relatively far into the water

• Corraline red algae build up calcium carbonate in their cell walls, and can be reef-building organisms

what is the economic importance of Polysiphonia

• agar-agar is a jelly-like food delicacy in japan

• agar used as culture medium in microbiology

  • cannot be digested by most microorganisms

• Agarose—purified from agar-used in molecular biology

  • gel electrophoresis

paper thin glossy sheets or nori: mineral rich wrap for rice, vegetable and seafood in sushi

what is the ecological of Polysiphonia

• corallines (calcified red algae) ]

• regarded as keystone pigments (species whose decline could cause the collapse or loos of entire biotic communities)

what is the importance of corallines (calcified red algae) ?

• help build and maintain coral reefs, which harbour diverse organisms

• by forming hard, flat sheets that consolidate and stabilize reef crests, coralline algae protect reefs from wave damage

• freshwater habitat

• coccoid and occur in loose colonies formed by the persistent cell wall of the parent cell following division

• have mitochondria with flat cristae

Phylum Glaucophyta

what are the chloroplasts known as in glaucophyta?

The chloroplasts are known as cyanelles

• with peptidoglycan layer (relic of the endosymbiotic origin of plastids from cyanobacteria)

• plastids contain chlorophyll a and phycobilins organized into phycobilisomes

what is the class of Glaucophyta

Class Glaucocystophyceae

what is the order of Glaucophyta

Order Glaucocystales

what is the family of Glaucophyta

Family Glaucocystaceae

Glaucocystis

• motile forms have two unequal flagella, which may have fine hairs