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Nonvascular Plants (Bryophytes).

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Presentation on theme: "Nonvascular Plants (Bryophytes)."— Presentation transcript:

1 Nonvascular Plants (Bryophytes)

2 Bryophytes

3 Seedless Nonvascular Plants
Spore Capsules Simplest land plants Evolved from green algae Can grow in a wide range of Environments When environment dries so does the plant Moss

4 General Characteristics
Lack vascular tissue (xylem & phloem) to carry water and food Water and food move in the plant by diffusion No strengthening tissue (xylem) so they cannot grow tall Most are between 2 and 20 cm high

5 General Characteristics
Have no true leaves or roots Have rhizoids – fine outgrowths of the stem to anchor the plant Have simple ‘leaf like structures’ that contain chlorophyll for photosynthesis Can absorb water through the surface of the plant Have no cuticle

6 General Characteristics
Reproduce by means of spores produced in sporangia of the sporophyte Which grows out of the visible plant Are homosporous = spores are all the same size Germinate immediately and grow into the green plant we can see (gametophyte) That produces male and female gametes

7 General Characteristics
Depend on water for fertilisation Male gametes have to swim in a film of water to reach the female gamete (egg)

8 General Characteristics
Two gametes fuse to form a zygote That develops into an embryo Which grows into the sporophyte Go through Alternation of generations (sporophyte & gametophyte stage) Gametophyte is dominant stage Reproduce by spores

9

10 Division - Bryophyta Sporophytes Gametophytes

11 Mosses Division Bryophyta Small, nonvascular plants
NO true roots, stems, or leaves Grow in moist areas (brick walls, as thick mats on the forest floor, on the sides of trees) Moss gametophytes

12 Moss growing on Moist tree trunk
Mosses Some can survive short dry spells Must grow close together for their life cycle H2O moves by diffusion from cell to cell Sperm must swim to egg through drops of water Moss growing on Moist tree trunk

13 Mosses Have a outer waxy Cuticle to prevent water loss
Have root like Rhizoids to anchor the plant, but NOT absorb water Leaf like gametophyte supports sporophyte with spore capsule

14 Sphagnum Moss Known for its moisture holding capacity
Absorbs 20 times its weight in water Used by florists to keep plant roots moist

15 Uses for Moss Plants Help decompose dead wood
EXTRA STUFF Uses for Moss Plants Help decompose dead wood Serve as pioneer plants on bare rock or ground Help prevent erosion Provide shelter for insects & small animals Used as nesting material by birds Peat moss is burned as fuel

16 Asexual Reproduction in Moss
The spore capsule is full of spores that must mature Once mature, the spore cap (operculum) comes off releasing spores Spores germinate (grow) when they land on moist soil

17 Sexual Reproduction in Moss
Moss alternate between a dominant haploid (1n) Gametophyte and a diploid (2n) Sporophyte Gametophytes produce gametes (eggs & sperm) containing half the chromosome number Sporophytes have a complete set of chromosomes & produces spores by meiosis

18 Sexual Reproduction in Moss
The sporophyte is smaller & attached to the gametophyte Sporophyte lacks chlorophyll & gets food from the gametophyte Sporophyte has a long, slender stalk (setae) topped with a spore producing capsule Spore Capsule setae

19 Sexual Reproduction in Moss
Eggs are large & immobile Produced in structures called archegonia

20 Sexual Reproduction in Moss
Antheridia forms many sperm cells Sperm cells capable of swimming to egg Sperm follow a chemical trail released by the egg

21 Sexual Reproduction in Moss
Fertilized egg (zygote) undergoes mitosis to develop Sporophyte Spore capsule of sporophyte makes haploid spores by meiosis Spores germinate into juvenile plants called protonema Protonema becomes the gametophyte

22

23 Division - Hepatophyta
Not in the syllabus Division - Hepatophyta

24 Liverworts Nonvascular Reproduce by spores
Alternation of generations with sporophyte attached to gametophyte Green, leafy Gametophyte dominant

25 Liverworts Need abundant water for fertilization
Grow on moist soil, rocks, or other moist surfaces Reproduce asexually by gemmae or by growing new branches Reproduce sexually by haploid spores Gemmae Cups Capsule

26 Division Anthocerophyta
Not in the syllabus Division Anthocerophyta

27 Hornworts Small, nonvascular bryophytes
Sporophytes Small, nonvascular bryophytes Gametophyte leafy and dominant like liverworts Archegonia & antheridia form inside the plant Zygotes develop into long, horn-shaped Sporophytes Gametophytes

28 Hornworts Horn-shaped Sporophyte capable of photosynthesis
Sporophyte attached to, but NOT as dependent on Gametophyte Sporophyte Gametophyte

29 The End


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