5 Characteristics of plants (embryophytes)
- Alternation of Generations
- Multicellular gametangia
- Multicellular sporangia
- Matrotrophic embryo
- Sporopollenin
Matrotrophy
“Mother Nutrition”
- Embryo is retained on mother gametophyte (feeds and shelters embryo)
- All land plants
Sporopollenin
Tough, decay resistant coat that surrounds land plant spores
- Protects from desiccation and disease
- All land plants
2 Groups of Embryophytes
- Bryophytes-3 divisions
- Tracheophytes (vascular plants)-7 divisions
Bryophyte Divisions
Anthocerophyta, Marchantiophyta, Bryophyta
Bryophyte characteristics
Lack vascular tissue
- Dominant gametophyte generation (free living and photosynthetic)
- Parasitic sporophyte
- No tissue specialization
Bryophyte gametophytes
- Dominant phase of life cycle
- Free living
- Persistant
- Thallus, “stem-leaf” structure with rhizoids
Bryophyte Sporophyte
Nonphotosynthetic and parasitic
- Attached to gametophyte
- Foot (embedded in gametophyte), seta, sporangium (capsule)
Seta
Elongated part of sporophyte for spore dispersal
Cool stuff about Bryophytes
Extremely diverse
- Can grow in harsh environments and on bare rock
- Can live in low light
Anthocerophyta (Hornworts)
Species diversity-8th Eco Divers-limited distribution -Most basal embryophyte 1. Gametophyte is thallus 2. Single chloroplast w/ pyrenoids 3. Sporophyte lacking a seta 4. Sporangium with basal meristem
Anthocerophyta Gametophyte
Simple thallus
- One chloroplast per cell with:
- Pyrenoids: starch organizing area
- Ancestral features
Anthocerophyta Sporophyte
Foot
- Seta absent
- Basal meristem-continuously produces new spores
Hepatophyta/Marchantiophyta (Liverworts)
Species Divers-4th Eco Divers- worldwide, moist shady areas 1. Oil bodies in cytoplasm 2. Gametangiophores 3. Gemmae Cups 4. Elaters in capsule
Hepatophyta Gametophyte
Complex, differentiated thallus
- Upper surface has pores, air chambers, photosynthetic tissue
- Lower surface has rhizoids
Gametangiophores (Hepatophyta)
- Fertile branches w. gametangia
1. Archegoniophores: bear archegonia (look like palm trees)
2. Antheridiophores: bear antheridia (stalk w/ flat head)
Gemmae Cups
Asexual propagules
- Splashed out by rain
- Hepatophyta
Hepatophyta Sporophyte
Located under surface of archegoniophore
-Foot, seta, short capsule
Capsule
Filled with spores
-Elaters: long skinny, twist in response to humidity and disperse spores
Bryophyta (the mosses)
Sp Divers-2nd Eco divers-worldwide, dominant in tundra, bogs, and wetlands 1. Protonema 2. "stem-leaf" structure 3. Unique capsules
Protonema
- Bryophyta
- Initial gametophyte growth phase
- Branching filaments, green and photosynthetic
- Buds produce adult gametophytes
Bryophyta Sporophyte
Foot, seta, capsule surrounded by calyptra
Calyptra
Remains of ventor (part of old archegonium)
- Ruptured when capsule is mature
- Differ in dehiscence mechanisms
Explosive dehiscence
Peat moss
- Capsule has lid called operculum
- Mature capsule dries and fills with gas
- Gas heats, capsule explodes, spores disperse
