Bryopsida Flashcards
What are the key features of the leaf-like structures in mosses?
The leaf-like structures are nearly one cell thick, with a midrib running lengthwise. They lack petioles, lobes, or divisions and contain chloroplasts for photosynthesis.
What is the function of rhizoids in mosses?
Rhizoids anchor the moss to substrates and assist in absorbing water and nutrients.
How do mosses transport water in the absence of xylem?
Water moves through capillarity along the plant surface and central strand of hydroids.
Define gametangia in mosses.
Gametangia are multicellular structures that produce gametes; they are located at the apices of leafy shoots.
What are the two types of gametangia, and what do they produce?
Archegonia produce eggs, while antheridia produce sperm.
Describe the structure of the archegonium in mosses.
The archegonium is cylindrical with a swollen base (venter) containing an egg and a neck with a canal for sperm entry.
How is the sperm attracted to the egg in mosses?
The archegonium releases chemicals like sugars and proteins that attract the sperm.
What is the role of the foot in moss sporophytes?
The foot anchors the sporophyte to the gametophyte and absorbs water and nutrients.
Explain the role of the calyptra in mosses.
The calyptra is a protective cap that covers the developing sporophyte.
Describe the structure and function of the seta in moss sporophytes.
The seta is a slender stalk that elevates the capsule, aiding in spore dispersal.
What is the operculum, and how does it aid in spore dispersal?
The operculum is a lid on the capsule that detaches at maturity to release spores.
What are peristome teeth, and how do they function?
Peristome teeth are membranous structures around the capsule rim that respond to humidity to regulate spore release.
How do spores in mosses germinate into gametophytes?
Spores germinate into protonema, which develops buds that grow into mature gametophytes.
What is a protonema, and how does it develop into a gametophyte?
A protonema is a filamentous structure that branches and produces buds, eventually forming a leafy gametophyte.
Describe the asexual reproduction process in mosses.
Cells from various parts of the plant form protonema, which grows into a mature gametophyte.
What environmental conditions are required for moss spore germination?
Spores germinate in damp, shaded, and nutrient-rich environments.
How do mosses adapt to humid conditions for reproduction?
They rely on external water for sperm motility and fertilization.
Define homothallic and heterothallic mosses with examples.
Homothallic mosses (e.g., Funaria) have male and female gametangia on the same plant, while heterothallic mosses (e.g., Polytrichum) have them on separate plants.
How do moss sporophytes obtain nutrients?
Sporophytes depend on the gametophyte for water and nutrients through the foot.
Explain the role of stomata on moss capsules.
Stomata facilitate gas exchange and remain open until the capsule ages.
How do paraphyses assist in moss reproduction?
Paraphyses are hair-like structures that provide support and prevent desiccation of gametangia.
What is the significance of chloroplasts in moss leaf cells?
Chloroplasts perform photosynthesis, providing energy for growth and reproduction.
How does capillarity help water movement in mosses?
Capillarity allows water to move upwards through narrow spaces on the plant surface.
Why are mosses considered non-vascular plants?
They lack true xylem and phloem for water and nutrient transport.
