Reproduction in Plants (Chapter 16) – Parts of a Flower, Pollination, and Post-Pollination

A comprehensive set of flashcards covering the parts of a flower, pollination types and traits, agents of pollination, and post-pollination processes as outlined in the lecture notes.

What is the function of sepals in a flower?

To enclose and protect the flower during the bud stage.

What is the function of petals in a flower?

Petals are modified leaves surrounding the reproductive organs; they attract pollinators with color and sometimes nectar guides.

What does the anther do?

Produces pollen grains; releases pollen when it matures.

What does the filament do?

A stalk that holds the anther in a position to disperse pollen grains.

What is a pollen grain?

Contains the male haploid gametes.

What is the stigma in a flower?

Receives the pollen grains.

What is the function of the style?

A stalk that connects the stigma to the ovary and guides the pollen tube.

What is the ovary's role?

Contains one or more ovules; typically becomes the fruit after fertilisation.

What is an ovule?

Found inside the ovary; contains the ovum and becomes the seed after fertilisation.

What is an ovum?

The female haploid gamete.

What is a carpel?

The female reproductive part consisting of the stigma, style, and ovary.

What is a receptacle in a flower?

The swollen end of the flower stalk that connects to and supports the flower.

What is the difference between unisexual and bisexual flowers?

Unisexual flowers have either male or female parts on a flower; bisexual flowers have both male and female parts on the same flower.

What is self-pollination?

Transfer of pollen grains from the anther to the stigma of the same flower or of a different flower on the same plant.

What is cross-pollination?

Transfer of pollen grains from the anther of one plant to the stigma of a flower on another plant of the same species.

What is a key feature of self-pollinating flowers?

Maturation of the male and female parts at the same time; stigma may be located below the anther; some bisexual flowers never open (example: Closed Bottle Gentian).

What are the advantages of self-pollination?

Only one plant is required; offspring inherit genes from the parent; less energy and pollen wasted; less dependence on external factors.

What are the disadvantages of self-pollination?

Less genetic variation among offspring; reduced adaptability to environmental changes; potential for weaker offspring over time.

What are the advantages of cross-pollination?

Greater genetic variation; offspring may inherit beneficial traits from both parents; more viable seeds that can survive longer.

What are the disadvantages of cross-pollination?

Requires two plants; depends on external pollinators like insects or wind; lower probability of pollination; more energy and pollen wasted.

What are the two main agents of pollination?

Insects and wind.

What are typical traits of insect-pollinated flowers?

Large, brightly colored petals; nectar present; pleasant scent; stigmas small and compact; stamens not pendulous; pollen larger with rough surfaces; nectar guides may be present on petals.

What are typical traits of wind-pollinated flowers?

Small, dull-colored flowers with no nectar; odorless; stigmas large and feathery and protruding; long, pendulous stamens with protruding anthers; abundant tiny, smooth pollen; no nectar guides.

What happens after pollination begins?

Pollen grains germinate on the stigma, pollen tubes grow down the style toward the ovary, and the pollen tube enters the ovule via the micropyle.

What is the micropyle?

A tiny opening in the ovule through which the pollen tube enters.

What happens when the pollen tube reaches the ovule and fertilisation occurs?

Male and female nuclei fuse to form a zygote; the zygote develops into an embryo, the ovule becomes a seed, and the ovary typically becomes the fruit.

What is a zygote?

The fusion of the male and female gamete nuclei; the early embryo.

What is the role of the embryo and seed in post-pollination development?

The embryo develops from the zygote; the ovule develops into a seed; the ovary develops into a fruit.

What example illustrates a flower that self-pollinates because it never opens?

Closed Bottle Gentian (Gentiana andrewsii).