BIOL 410 - Pollination & Ripening

Why do anthophyta pollen grains have no wings?

Delivered by insects.

Where does the pollen land on in flowering plants? What about gymnosperms?

flowering plants: stigma

gymnosperms: cones

How is the ovule in a flowering plant different than the ovule in a gymnosperm?

It has fewer cells.

What is the purpose of synergids?

Attract the pollen tube.

What happens to all the floral parts preset when the pollen tube is growing down to the egg in the ovule?

Post pollination, the stamens, petals, stigma, and style have fallen off. The base of the carpel (ovary) remains because the ovules are there. They are inside there and protected. Sperm is present for fertilization and you no longer want to attract pollinators.

Why is it important for abscission to occur?

Stop attracting insects. All flower parts are gone except ovary, and the ovary should not be eaten by insects.

Is there an embryo inside the gametophyte with the egg? (immature seeds)

No.

What is double fertilization in flowering plants?

One sperm fertilizes the egg to make the zygote. The other sperm fertilizes the central cell (in the middle of the gametophyte) to make endosperm.

What happens to the embryo once the sperm fertilizes the egg inside the ovule?

Embryo starts maturing inside.

How can we tell when the embryo is not mature yet?

The endosperm is not completely digested yet. Not ready for seed dispersal yet.

When will the mature seed start food ripening?

Once the embryo has consumed the endosperm and it fills the entire seed.

When does ripening begin?

Ovary enlarging (sucrose enters the fruit and breaks down into glucose - ATP - and fructose - sweetener)

Why are anthocyanin/ carotenoids synthesized?

To attract animals to disperse the mature seeds with an embryo on the inside of the fruit.

How do tumbleweed, dandelion, and cotton disperse their seeds?

Wind dispersal.

Why do some fruits harden and trap air?

For flotation

ex. coconut

What is the largest fruit in the world?

Coco De Mer. Found east of Africa. 65 or more pounds.