bryophytes Flashcards
1
Q
Land plants differ from Charophyceae by
A
- Male and female gametangia called antheridia and archegonia that have a protective layer (sterile jacket layer)
- Zygote and developing embryo are retained within the archegonium on the female gametophyte
- Sporophyte is multicellular=>increases the number of meiosis and the number of spores produced per single fertilization event
- Spores with walls containing sporopolleninresist decay and drying
- Tissues produced by apical meristem
o Meristem = region of embryonic cells that makes new cells; like stem cells
2
Q
features
A
- No vascular plants
o Lack water (xylem) and food tissues (phloem)
o So they’re flat to compensate for this - Lack true leaves, stems, and roots
- Have superficial cuticle and pores—liverworts
3
Q
structure
A
- Thallose
- Flat and thin gametophyte—undifferentiated
o Helps with uptake water and CO2
o Leaves small w/o veins
o Stems w/ conducting cells
o Rhizoids for fixation
4
Q
asexual reproduction
A
- Fragmentation or producing gemmae
o Small pieces of gametophytes are detached and then regenerate an entire gametophyte (identical)
Liverworts gametophyte produces gemmae in cups and rain helps with dispersal
5
Q
sexual reproduction
A
- Gametophytes can be dioecious (male/female) or monoecious (both sex present but separate)
o Flagellated sperms (n) produced in antheridia
o Eggs (n) produced in archegonia
Venter and neck - After fertilization the zygote (2n) attached to female develops sporophyte (2n)
o Female gametophyte (n) provides sugars AA’s = matrotrophy
o Placenta is transfer of cells with highly branched cell wall ingrowth. Incr. SA - Mature sporophyte, meiosis produces spores (n)
o Spores released from sporangia and dispersed by winds
o Spores germinate into gametophyte
o Directly or through protonema in all mosses and some liverworts
6
Q
Marchantiophyta (Liverworts)
A
- Leafy and thallose species
- Gametophyte grows directly from the spore
- Thin thallus with single celled rhizoids and scales for fixation to rocks and moist soils
- Gametangia born on gametophores
- Sporophyte dominant in alga
- Spore dispersion
o Released form sporangia and dispersed by wind
o Elaters are elongated cells that help with dispersion
Sensitive to humidity
Twist
7
Q
Sphagnum Moss
A
- Abundant
- Peat is accumulation and compression of sphagnum moss in cold wet places
- Sphagnum differs from other bryophytes
o Protonema one layer thick
o Leaves made of dead cells surrounded by small living cells
o Absorbs water
o Explosive operculum
Burst and spores released
8
Q
Bryophyta (mosses)
A
- Leafy gametophytes that develop from buds on filamentous protonemata
- Have specialized cells for water and food conduction
o Handrom (central strand) Leptom (surrounds hadrom)
o Hydriods—transport water/minerals, are elongate cells with end walls , permeable to water , no living protoplasm (DEAD CELLS)
o Leptoids—conduct sap (water +sugar), elongate cells with end walls, protoplast present at maturity but nucleus is degenerate (LIVING CELLS) - Gametangia produced at tip of main axis/lateral branches
- Sporophytes born on female gametangia
o Sporophyte grows, venter of archegonium enlarges = calyptra falls off, operculum open to expose peristome - stomata
9
Q
Anthocerophyta (Hornworts)
A
- Resemble thallose liverworts
- Symbiotic relationship with cyanobacteria
- stomata
10
Q
MABS
A
MARCHANT–LIVERWORTS
ANTHO–HORNWORTS
BRYO–MOSS
SPAGNUM–MOSS