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sporic, byro, marchantia, liver worts, hornworts, peat, moss
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Bryophytes
The Bryophytes
Similarities to green algaeContains chlorophyll A and B and stores starchCell walls made of cellulose, hemicelluloses, and pectic substancesNon-‐motile egg retained after fertilization
Some have zygote coverings resembling integumentsAsymmetrically flagellated sperm with flagella extending from the side rather than endAlso begin to see prominent male and female gamete separation*Presence of sporopollenin
Bryophytes
Distinguishing characteristicsPresence of male and female gametangia in a layer called a sterile jacket
Antheridia and archegoniaRetention of zygote and developing multicellularembryo (sporophyte) within archegoniaPresence of multicellular diploid sporophyte
Represents permanent shift to sporic meiosisSpores ** containing sporopollenin
Charophytes had embryos w/ sporopollenincharophytes (green algae) have spores w/??
Tissues produced by an apical meristem
Sporic Meiosis
This is fine when fertilization via flagellated sperm is easy (aqueous env)
Fertilizations only can make
Q: What about terrestrial environments where fertilization by flagellated sperm is tough???
Sporic Meiosis
This is fine when fertilization via flagellated sperm is easy (aqueous env)
Fertilizations only can make
Q: What about terrestrial environments where fertilization by flagellated sperm is tough???
A: Mitosis of zygote once = 8 haploid cells (6 times =256)
Bryophytes
Still retain gametophyte as dominant and nutritionally independent stage
Sporophytes contain only single sporangia (compare to a pine tree)
Lack true specialized vascular tissue
Undifferentiated spores!!
Liverworts
Phylum Hepatophyta
Two major groupingsThallus
Leafy
Marchantia
Most well known thalloidliverwortContains antheriophoresand archegoniophores
Modified 1n tissue containing a sporophytewhich consists of a foot, seta, and capsuleNo direct connection between 1n and 2n
Oogonium of Chara a green algae (will only contain a single 2n embryo)
Embryo undergoing mitosis in
similar to oogonium of Chara
Marchantia
Antheridia Archegonia
Note: these are not the
Hornworts
Phylum Hepatophyta
Small phyla ~100 species
Unisexual or bisexual gametophytes
Sporophytes are often
gametophyte
Hornworts
Sporophytes green, w/ stomata, and photosynthetic
First evidence of independence in sporophyte stage
Mosses
Most mosses are not mosses?Reindeer moss
Scale moss
Club moss
Spanish moss
Sea/ Irish moss
Mosses
Three groupings of mossesPeat mossesGranite mossesBryidae mosses
Bryidae are the closest relatives to vascular plants
Peat/ Spaghnum
Distinctive operculum/ pseudopodiumsporophyte
Cellular structure allows for incredible water retention
Peat Ecology
Peat bogs occupy roughly 10% of terrestrial surfaceMakes peat one of the most abundant plants on earthStores ~400 billion tons of carbonLocations in temperate/ boreal/arctic and anoxic conditions makes bogs carbon sinks
True Mosses
Class BryidaeReduction in gametangia
Sessile and apical (compare to Marchantia)
Have primitive vascular cellsHadrom water conductionLeptoids sugar conducting
True Mosses
Evidence of insect interactions at two different stages of moss reproduction
Brightly colored sporophytes may facilitate insect mediated dispersal of sporesBrightly colored bracts on the tops of gametophytes may facilitate movement of sperm