Wednesday, 15 March 2017

Vascular Plants

Vascular Plants (Phylum Tracheophyta)

  • Tracheids - Specialised cells for conducting water and supporting tissues (forming the xylem vessels)
  • All SPOROPHYTES in this group are larger than the gametophytes and have ROOTS, STEMS AND LEAVES.
  • can be further sub divided into the non- sees tracheophytes and the seed plants

THE SPERMATOPHYTA 'Seed Plants';


Now represented by two Phyla:

- The Gymnosperms:
 ( Cycads, Gingkos, Gneetophytes, Confiers)

- Angiosperms
 (Magnoliphyta or flowering plants)

COMMON THINGS IN ALL SEED PLANTS;

  • Seeds
  • Reduced Gametophytes
  • Heterospory: Spored of two different sizes and sexes
  • Ovules: Female gametophyte, protected by tissues of sporangium
  • Pollen: Male Gametes (Sperm cells)

THE ALTERNATION OF GERNERATION IN THE SPERMATOPHYTA;


 
  • The gametophyte generation is reduced to a very small, simple stage (only a few cells!).
  • The gametophyte develops partly or entirely whilst it is still nutritionally dependent on the sporophyte. 

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