The flower
This presentation is the property of its rightful owner.
Sponsored Links
1 / 7

THE FLOWER PowerPoint PPT Presentation


  • 220 Views
  • Uploaded on
  • Presentation posted in: General

THE FLOWER. A flower is a structure specialized for sexual reproduction. A COMPLETE flower has sepals, petals, stamens and carpels. An INCOMPLETE flower is missing one or more of the parts listed for a complete flower. PERFECT vs. IMPERFECT FLOWERS.

Download Presentation

THE FLOWER

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


The flower

THE FLOWER

  • A flower is a structure specialized for sexual reproduction.

  • A COMPLETE flower has sepals, petals, stamens and carpels.

  • An INCOMPLETE flower is missing one or more of the parts listed for a complete flower.


Perfect vs imperfect flowers

PERFECT vs. IMPERFECT FLOWERS

  • Perfect flowers have both stamens and carpels.

  • Imperfect flowers are either staminate (having stamens but no carpels) or carpellate (having carpels but no stamens).


Monoecious vs dioecious plants

MONOECIOUS vs. DIOECIOUS PLANTS

  • Monoecious plants have both staminate flowers and carpellate flowers on the same individual plant.

  • Diocious plants have staminate and carpellate flowers on separate individual plants of the species.


Alternation of generations

ALTERNATION OF GENERATIONS

  • An alternation of multicellular haploid (n) and diploid (2n) generations.

  • The sporophyte (2n) produces haploid spores.

  • The spores divide by mitosis to produce haploid gametophytes.

  • The gametophytes produce gametes by mitosis. Fertilization occurs: n+n=2n


Pollen grains

POLLEN GRAINS

  • A pollen grain is an immature male gametophyte.

  • Pollen grains are extremely durable; they have tough coats.


Formation of pollen

FORMATION OF POLLEN

  • Within the sporangial chamber of the anther, diploid microsporocytes undergo meiosis to form 4 haploid microspores.

  • The haploid microspore nucleus undergoes mitosis to form a generative nucleus and a tube nucleus.


The flower

  • The wall of the microspore thickens and becomessculptured into a species-specific pattern.

  • The pollen grain has 2 nuclei and is the immature male gametophyte.

  • When the anther opens to release pollen or after pollen lands on the stigma, the generative nucleus divides to form two sperm nuclei, which are the male gametes. The pollen grain is now mature.


  • Login