Plant Biology: Charophytes and Embryophytes

Study Notes

Charophytes and Plants

Charophytes are protists that share similar adaptations with land plants.
They have in common with plants: sporopollenin, cellulose in the cell wall, flagellated sperm, and phragmoplast.
Sporopollenin provides protection from the elements and is important for the evolution of land plants.

Embryophytes

Developing embryos are contained, giving them a better source of food and protection until they can move outside.

Plant Life Cycles

Antheridia and Archegonia play a role in plant life cycles, with sperm swimming from antheridia to archegonia to fertilize the egg.
Seeds allow offspring to survive for long periods in harsh conditions prior to germination.
Vascular tissue allows plants to grow tall and transport water and nutrients between distant roots and shoots.

Bryophytes

Bryophytes include mosses (phylum bryophyta), liverworts (phylum hepatophyta), and hornworts (phylum anthocerotophyta).
The life cycle of Bryophytes involves:
- Gametophyte stage: produce haploid gametes
- Sporophyte stage: produce haploid spores
In mosses, the sporophyte has a seta and capsule, while in liverworts, the sporophyte lacks a seta.
In hornworts, the sporophyte also lacks a seta.

Seedless Vascular Plants

Seedless Vascular plants differ from Bryophytes in that they grow much taller due to vascular tissue, and are sporophyte-dominant.
Vascular tissue is an important adaptation for transportation of water, minerals, and sugars.
Xylem transports water up from roots to leaves, while phloem transports sugar back down to roots.
Sporophylls are leaves with sporangia, differing from macrophylls or microphylls.
Homosporous plants have one type of spore, while heterosporous plants have different types of spores in the sporophyte.

Vascular Seedless Plants

Phylum lycopodia includes club mosses (homo), quillworts (hetero), and spike mosses (hetero).
Phylum monilophyta includes horsetails (equisetum), fern, psilotum (homosporous), and whisk ferns (homosporous).
Whisk ferns are considered living fossils because they have remained unchanged for a long time.

Comparison of Plant Groups

Bryophyte life cycle differs from Seedless Vascular, Gymnosperm, and Angiosperm life cycles.
Water is required for sperm to swim and fertilize the egg in plant life cycles.

Description

Learn about the characteristics and adaptations of charophytes, embryophytes, and their role in plant evolution. Understand the similarities and differences between these plant-like protists and true plants.