Chapter 23: Angiosperms

Angiosperms

Flowering plants

What are the angiosperm seeds enclosed in?

Carpel that resembles a leaf that has folded over and fused at the margins

What are pistils composed of?

A single carpel, or two or more united carpels

Where do angiosperm seeds develop from?

Ovule within carpel

What does the ovary of an Angiosperm become?

A fruit

What is the pistil of an Angiosperm composed of?

A single carpel, or two or more united carpels

Where do Angiosperm seeds develop from?

Ovule within carpel

What does the ovary of an Angiosperm become?

A fruit

All angiosperms are grouped within:

Phylum Mangnoliophyta

What are the two classes of Phylum Mangnoliophyta?

Magnoliospida, Liliopsida

Which group does Magnoliopsida belong to, monocots or dicots?

Dicots

What do DNA and cladistics evidence suggest about dicots (groups)?

Two groups of dicots should be recognized

Which group does Liliopsida belong to, monocots or dicots?

Monocots

Which part of the Liliopsida flower is modified?

Stem bearing modified leaves

Liliopsida is known as the “Most _______ “:

Most primitive flower

What is the flower structure of Liliopsida?

Long receptacle, spirally arranged separate flower parts, flattened and numerous stamens and carpels

What do Phylum Magnoliaphyta have a great variation in?

Size

What is the number of parasitic Phylum Magnoliophyta species?

Approximately 4,000 species

Where is food and water intercepted in Phylum Magnoliophyta?

Xylem and phloem (host)

What are some Phylum Magnoliophyta considered to be?

Saprophytes, orchids

Heterosporous

Different female and male gametophytes

Which phase is dominant in Phylum Magnoliaphyta (the Flowering plants)?

Sporophytes

What do the male gametophytes consist of in flowering plants?

Germinated pollen grain with three nuclei

What are female gametophytes in flowering plants reduced to?

Only a few cells, while enclosed within sporophyte tissue

Where does diploid megasporocyte differentiate in?

Ovule

What process do female gametophytes undergo?

Meiosis

What do female gametophytes produce after undergoing meiosis and how many degenerate?

Four haploid megaspores, three degenerate

What happens to the remaining cells from meiosis division?

Enlarges

What does nucleus divide to produce after undergoing meiosis?

8 nuclei (without walls)

What do the outer two ovule layers differentiate into that later become the seed coat of a Gametophyte?

Integuments

What is found at one end of the ovule during the development of Gametophytes?

Micropyle

How many groups do the 8 nuclei from inside of a female gametophyte cell?

Two groups, 4 near each end of cell

Where do the nuclei from each group in a female gametophyte migrate to?

Cell middle, forming central cell

What forms around the remaining six nuclei of a Female Gametophytes?

Cell walls

What were found at the opposite end of a female Gametophyte?

Three antipodals (no apparent function)

What is a female Gametophyte (megagametophyte, embryo sac)?

A large sac containing 8 nuclei, 7 cells

Where does the formation of male gametophytes take place?

In anthers

How many patches of Microsporocyte cells differentiate in anther?

Four patches, corresponding to pollen sacs

What does Microsporocyte in male gametophytes undergo meiosis to produce?

A quartet of haploid microspores

What are the three important changes microspores undergo?

Dividing by mitosis, separation of microspores, wall becoming two-layered

Exine

Finely sculpted, outer layer of male gametophytes

What does the outer layer of a male gametophyte contain?

Chemicals that may react with chemicals in stigma

What do generative nucleus in male gametophytes later divide to produce?

Two sperm

Pollination

Transfer of pollen grains from anther to stigma

Where do pollen grains germinate during self-pollination?

On stigma of same flower

Fertilization

Union of sperm and egg

What are the different methods of pollination?

By insects, wind, water, animal, or gravity