1. Nonvascular Plants
Ch – Dec 3, 2014

2. NONVASCULAR PLANTS Nonvascular plants lack vascular tissue
Have a “leafy” appearance but do not have true roots, stems and leaves
Only have rootlike, stemlike, leaflike structures

3. NONVASCULAR PLANTS
Gametophyte is the dominant generation in nonvascular plants
i.e. the generation that we recognize as the plant
Flagellate sperm swim in a continuous film of water to the vicinity of the egg
Sporophyte develops from the zygote, is attached to and derives its nourishment from the gametophyte shoot

4. Bryophytes
Life cycles of mosses and other bryophytes are dominated by the gametophyte stage
Bryophytes are represented today by three phyla of small herbaceous (nonwoody) plants
Liverworts, phylum Hepaticophyta
Mosses, phylum Bryophyta
Hornworts, phylum Anthocerophyta

5. Bryophytes LIVERWORTS (PHYLUM HEPATOPHYTA) Gametophore of
HORNWORTS (PHYLUM ANTHOCEROPHYTA)
MOSSES (PHYLUM BRYOPHYTA)
Gametophore of
female gametophyte
Marchantia polymorpha,
a “thalloid” liverwort
Foot
Sporangium
Seta
500 µm
Marchantia sporophyte (LM)
Plagiochila
deltoidea,
a “leafy”
liverwort
An Anthoceros
hornwort species
Sporophyte
Gametophyte
Polytrichum commune,
hairy-cap moss

6. Liverworts Have no true roots or shoots Require water to reproduce
Have no or very little leaf structure
Cannot live in sporophyte form
Exists in two types
Flat, lobed thallus (body)
Leafy (are more numerous)

7. Liverworts Marchantia Smooth upper surface
Lower uracea has numerous rhizoids (rootlike hairs - project into the soil)
Reproduces both asexually and sexually
Gemmae cups on the upper surface of the thallus contain gemmae
Gemmae = group of cells that detach from the thallus and can asexually start a new plant

8. Liverworts Sexual reproduction depends on:
Dish-headed stalks that bear antheridia (flagellated sperm are produced)
Umbrella-headed stalks that bear archegonia (eggs are produced)
Following fertilization, tiny sporophytes composed of a foot, short stalk and a capsule begin growing within archegonia
Windblown spores are produced within the capsule

9. Mosses Land plant Most have no vascular tissue
Majority of life spent in gametophyte
Need water to breed
No leaves or roots
Sporophytes are capsules on stalks

10. Mosses Most reproduced asexually by fragmentation
Gametophyte of mosses have two stages
First, there are algalike protonema (branching filament of cells)
After three days of favorable growing conditions, upright leafy thalli appear at intervals along the protonema.

11. Mosses
Rhizoids anchor the thalli, which bear antheridia and archegonia
Antheridium – consists of a short stalk, an outer layer of sterile cells and an inner mass of cells that become the flagellated sperm
Archegonium - which looks like a vase with a long neck, has a single egg located inside its base

12. Mosses Dependent sporophyte consists of a:
foot (grows down into the gametophyte tissue)
stalk
upper capsule, or sporangium (windblown spores are produced)
At first, sporophyte is green and photosynthetic
At maturity it is brown and nonphotosynthetic
WHY?
Gametophyte is the dominant generation
It seems consistent for spores to be dispersal agents

13. Mosses

14. Hornworts Free-floating aquatic plant, or land plant
No vascular tissue
No true leaves or roots
Can live in both gametophyte and sporophyte forms

15. Adaptations and uses of Nonvascular Plants
Mosses
Better at living on walls, fences and even in the shady cracks of hot, exposed rocks
For these microhabitats, being small and simple seems to be a selective advantage
Colonizing bare rock = help convert rocks to soil that can be used for the growth of other organisms

16. Adaptations and uses of Nonvascular Plants
Bogs - ground is wet and acidic
Dead mosses, especially Sphagnum, do not decay
Accumulated moss called peat or bog moss
Commercially important
Can be used as fuel
Nonliving cells can absorb moisture

17. Complete “Check Your Progress”
pg. 606 #1-2
Handout