Reproduction in plants

What do plants produce for sexual reproduction?

Flowers.

What ensures that fertilization takes place?

Gametes

After fertilization what 2 things develop?

a fruit a nd seed

The fruit helps with

seed dispersal

The seed helps with

Growing new plants

Pollination

Transfer of pollen from the anther to the stigma

Pollination leads to

fertilization

Name 2 types of pollination

self pollination and cross pollination

Self - pollination

Pollen grains are transferred to the stigma of the same flower or stigmas of other towers on the same plant.

Cross pollination

Pollen grains are transferred to the stigma of flowers of different plants in the same species

Name the three agents of pollinations.

Wind, birds and insects

Note

Once pollination has occurred the male gamete still was to reach

The female gamete for fertilization to occur

The ovule develops into a

Seed

The zygote divides forming

An embryo

What does the embryo consist of?

Plumule(shoot), radicle (root) and are or two cotyledons (seed leaves)

Endosperm

Remains as a food store in endosperm seeds eg- maize but is absorbed by the cotyledons in non - endospermic seeds cg. Peas and beans.

Integuments become

Testa after hardening with the micropyle still present.

The ovary grows into

Fruit which contain seeds

What parts of the flower shrivel and drop off?

Stigma, style, stamens and petals. The sepals might stay or drop.

Pollen grains land on the stigma. What happens after

It absorbs the nutrients present swells and grows a pollen tube

Where does this pollen tube grow?

The pollen tube with two male nuclei in its tip grows down the style by secreting enzymes to digest a pathway.

How is the zygote formed?

The pollen tube grows through the micropyle of ovule and bursts.one male nucleus fuses with a female gamete (ovum)

How is the endosperm formed?

Other male nucleus fuse with the endosperm nucleus.

Note

Fruits protect developing seeds and help in dispersing seeds.

What is the wall of the fruit called?

pericarp

The pericap is composed of three layers, what are they called?

epicarp, mesocarp and the endocarp

Name the 2 main types of fruits

Succulent and dry fruits

Succulent fruits

One or more layers of the pericarp are juicy and fleshy.

Dry fruits.

The pericarp is thin and dry eg. Capsule of castor oil and pride of Barbados

Name 2 reasons why seed dispersal is important?

To prevent overcrowding which prevents competition for light, water, minerals.

To allow colonization of new habitats.

Name the 4 types of seed dispersal

Animals, wind, water + mechanical

Dispersal by animals

Succulent fruits eg. Mango or hooked fruits like castor oil

Dispersal by wind

Winged fruit or seeds or parachute fruit or seeds.

Dispersal by water

Coconut

Mechanical dispersal

Pride of Barbados