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Nonvascular Plants

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

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Nonvascular Plants

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  1. Nonvascular Plants (Bryophytes)

  2. Bryophytes

  3. Spore Capsules Seedless Nonvascular Plants 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. Division - Bryophyta Sporophytes Gametophytes

  10. 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

  11. 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

  12. 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

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

  14. 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

  15. 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

  16. 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

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

  18. Sexual Reproduction in Moss • Eggs are large & immobile • Produced in structures called archegonia

  19. 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

  20. 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

  21. Not in the syllabus Division - Hepatophyta

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

  23. 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

  24. Not in the syllabus Division Anthocerophyta

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

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

  27. The End

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