Plant Biology – Day 17 Friday October 19, 2012
Bryophytes Liverworts, hornworts, mosses.
- Alternation of Generations:
o Gametophyte (N) life form most obvious
o Sporophyte – grows out of the ♂ gametophyte
- The sporophyte generation is dependent on the gametophyte life form.
Phylum Hepaticophyta (Liverworts)
a. Thalloid aid Liverworts
- No root structure but have extensions from the epidermal cells – rhizoids, scales
- Chlorenchyma tissue
- Pores in the epidermis Gaseous exchange
Example: Marchantia Asexual and sexual reproduction
- Occurs in gametophyte life phase
- Gemma cup – Rain splashes out pieces of the epidermis new Marchantia
- Have separate ♀ and ♂ thalli – N (haploid)
- ♂- antheridia – at top of gametophore – stalks antherdia
- ♀- archegonia – on stalks (archegoniaphore)
- Fertilization occurring flagellated sperm from the antheridia are going to fertilize
and egg in one of the archegonians.
- Need moisture to occur for fertilization
- Zygote forms 2N sporophyte grows out of the archegonian. Ie – this life phase is
dependtant on N phase.
- 5 sporophyte foot (anchors to the ♀ gametophyte)
sota (stalk) – holds the sporophyte
- sporophyte – fertile tissue sporocytes – 2N meiosis spores