Angiosperm Reproduction

What is an angiosperm?

A flowering plant whose seeds develop enclosed within an ovary that becomes a fruit.

What are the two main functions of a flower?

Facilitate pollination and produce/nurture male and female gametophytes.

What is a stamen?

The male flower structure, consisting of an anther and filament.

What does an anther produce?

Microspores that develop into pollen grains.

What is the function of a filament?

It supports the anther.

What is a pollen grain?

An immature male gametophyte containing a tube cell and generative cell in the course notes.

What does the pollen tube do?

Grows toward the ovule and transports two sperm cells.

What is a carpel?

The female reproductive structure, including stigma, style, and ovary.

What is an ovary?

The flower structure containing ovules; it typically develops into the fruit after fertilization.

What is an ovule?

A structure containing the megasporangium/female gametophyte and enclosed by integuments.

What happens to the megaspore mother cell?

It undergoes meiosis to produce four megaspores; usually three degenerate and one remains.

How does the surviving megaspore form the female gametophyte in the outline?

It undergoes mitosis and develops into a seven-cell structure.

Where is the egg cell located?

Within the female gametophyte inside the ovule.

What is pollination?

Transfer of pollen to a receptive stigma or ovule, depending on the plant group.

What is self-pollination?

Pollen reaches the female reproductive structure of the same plant/flower.

What is cross-pollination?

Pollen is transferred between different plants of the same species.

What is fertilization?

Fusion of sperm and egg to form a zygote.

What is double fertilization?

One sperm fertilizes the egg to form the zygote; the other fuses with the central cell nuclei to form endosperm.

What does the zygote develop into?

The embryonic sporophyte.

What does endosperm do?

Provides nourishment to the developing embryo.

What does an ovule become after fertilization?

A seed.

What does the ovary usually become after fertilization?

A fruit.

What is a seed coat?

The protective covering derived from ovule integuments.

What is a fruit?

A mature ovary, often containing seeds; it can aid seed protection and dispersal.

How many sperm cells are delivered by a typical angiosperm pollen tube?

Two.

What is the role of the pollen tube cell?

It grows to deliver sperm to the ovule.

What is the role of the generative cell in pollen?

It divides to produce the two sperm cells.

What is the ploidy of the angiosperm embryo?

Diploid (2n).

What is the ploidy of endosperm in the typical angiosperm double-fertilization pattern?

Usually triploid (3n).

What is the overall angiosperm life-cycle trend?

The sporophyte is dominant; male and female gametophytes are highly reduced.