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6. Sexual reproduction in plant with seeds. - Coggle Diagram
6. Sexual reproduction in plant with seeds.
Reproductive organs inside a
flower
, that have the following parts:
Outer envelope
Two structures:
Calyx
(green
sepals
)
Corolla
(
petals
, usually brightly coloured).
Covers and protects reproductive organs.
Reproductive organs
Stamen
(an
anther
and a filament that supports it. The anther contains
pollen grains
with male gametes).
Pistil
(shaped like a bottle. Top part (
stigma
), neck (
style
), base
ovary
, where the ovules, the female gametes, are produced).
Responsible for the production of gametes.
Peduncle
(joins flower to the stem).
Pollination
Occurs in several ways:
By animals:
Pollen sticks to insects and birds, which carry it to another flower, for example, bees and hummingbirds.
By wind:
Pollen is randomly blown about and dispersed.
Some plants (holm oaks),have flowers with long stamens so it is easier for the pollen to be carried by the wind.
This process is called
pollination
.
Colourful, attractive flower like orchid draw the attention of pollinating insects.
Pollen grains are transferred from the anthers of one flower to the stigma of another flower.
Fertilization and formation of fruit
After fertilization, ovules becomes the
seed
. Seeds have three basic parts:
Nutrient reserves
or
endosperm
, which feed the new plant until it develops green leaves and can carry out photosynthesis.
An outer covering (
seed coat
), that protects the seed until germination.
Embryo
, which develops into a new plant.
Ovary is slowly transformed into a
fruit
that protects seed.
Pollen grain travels down the tube and unites with the ovule (
fertilization
).
Seeds are circulated or dispersed when animals eat the fruit and excrete the seeds.
Pollen grain reaches the stigma and a
pollen tube
grows down the pistil to the ovule.
Some plants, like the maple tree, have fruit that take advantage of the wind for dispersal.
Germination
Radicle
, a small root, is the first structure that the seed produces.
Anchor the plant to the ground.
It's occurs when seed falls to the ground and the conditions are favourable.
Cotyledons
provide the nutrients needed for growth.
