Bryophytes: Liverworts, Hornworts and Mosses. Bryophytes

Plant sciensts recognize two kinds of land plants

§Bryophytes, or nonvascular plants §Tracheophytes , or vascular plants.

Distribuon tropical rainforests, arcc tundra, and desert boulders

Chlorophyta and Bryophyta

Charophyta

§Chloroplasts with grana §Disintegraon of nuclear membrane during mitosis §Phragmoplast during cytokinesis §Oogamus sexual reproducon §Zygotes remain aached to the parental thalli §The parental cells develop transfer cells involved in bringing sugars to the zygote §Plasmodesmata Bryophytes and other land plants. Kingdom Plantae

§ Mulcellular diploid sporophyte

§ Producon of sporogeneous ssue

§ Tissues produced by an apical meristem. Bryophytes. Non vascular plants

Specialized cell for conducon

Not lignified cells

Large free living gametophyte

Sporophyte

§Achlorophyllous §“Parasic” on the gametophyte §Unbranched §One sporangium

Plasmodemata

Bryophytes. Non vascular plants

Cucle Pores Rhizoids

Disk-shaped plasds in the thalli

hexagonal leaf cells with central pore Reproducon of Bryophytes archegoniophore Asexual: (female sex organ)

•Fragmentaon •Gemmae

Sexual:

•Antheridia •Archegonia •Gametpohytes are haploid •Gametes produced by mitosis

Bryophytes need water for ferlizaon to occur.

Sporophyte of bryophytes.

Sporophyte of mosses and hornworts contain stomata and two guard cells.

•brings up nutrients from the gametophyte through the placenta.

Spores covered with sporopollenin.

§Cellulose §xylan §lignin §Lipids

Extremely resistant to decay and chemicals

Bryophyta:Phylums/Divisions

§ HEPATOPHYTA - the Liverworts § ANTHOCEROPHYTA - the Hornworts § BRYOPHYTA - the Mosses

HEPATOPHYTA (hepacs) - the Liverworts The Liverworts (wyrt= herb) 6,000

Gametophytes develop directly from spores but some produce protonemata

Gametophyte §leafy §thalloid

Thalloid liverworts

Differenaon of the thallus into

1. an upper photosynthec region with air chambers

2. a ventrally storage zone with abundant lipid reserve and rhizoids. Thalloid liverworts

Marchana produces the sex organs in Sporophyte • Antheridiophores è antheridia. • Archegoniophores è archegonia.

Elaters to help in scaering the spores.

Fragmentaon Gemma cups

Leafy liverworts

4000 species

Leaves generally are monostromac

Antheridia produced on the androecial branches.

The archegonium is surrounded by the perianth. ANTHOCEROPHYTA - the Hornworts

100 species

Gametophyc thallus lobed or dichotomous

The thallus has internal chambers with Nostoc

Rhizoids are unicellular

Stomata

Most species are bisexual.

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Gametangia develop from superficial cells but never project above the surface

Sporophyte:

Foot embedded in the gametophyte Long capsule or sporangium. intercalary meristem between the foot and the capsule meristem remains acve indeterminate growth photosynthec

BRYOPHYTA - the Mosses

12,000 species

Protonema

Mulcellular rhizoids

Gametophyte •Leafy with more than three ranks of blades •Chlorophyllous •May or may not branch.

BRYOPHYTA - the Mosses Protosphagnales appear about 290 million years ago in the Permian.

Sphagnum has apical gametangia

Sporophyte capsules develop on the pseudopodia

BRYOPHYTA - the Mosses

“explosive” operculum

§closes the opening of the sporangial capsule

Sphagnum can absorb water up to 20 mes its dry weight

Sphagnum releases large amount of H+

Class Andreaeidae 101 species granite or calcareous rocks in northern latudes

Rhizoids consist of two rows of cells

Sporophyte •Foot •Capsule üfour valves that open when is dry and close when is moist. Class Bryidae Protonema

§uniseriate branched system that precedes the gametophores. §major photosynthec role.

Mulcellular rhizoids present

The sporangium opening with peristome.

Aendance

What evidence is there in support of a charophyte ancestry for plants?