pollination and fertilisation in flowers gcse
DESCRIPTION
A presentation about the pollination and fertilisation processes that take place in a flower.TRANSCRIPT
Reproduction in Flowering Plants
Flower• Sexual reproductive structure
• Produces egg and sperm
• Fertilization takes place inside the flower
Pistil*Stigma –top of the pistil,Sticky surface for pollen to
stick to*Style – connects the stigma to
the ovary*Ovary –contains ovules ( eggs)
Stamen*Anther – produces male
nuclei enclosed by pollen grains.
*Filament – holds the anther up
Female reproductive organ
Male reproductive organ
PollinationSelf-
pollination
• Pollen from the anther is transferred to the stigma
Cross Pollination• Pollen from the anther of one plant
is transferred to the the stigma of a different plant
• When a pollen grain lands on the stigma, it germinates and a pollen tube grows down through the style to an ovule (egg)
• The ovary and fertilized ovule develop and ripen.
*The ovule forms the seed and the ovary forms the fruit.
• A fruit is a ripened ovary
The plant embryo uses food stored in the cotyledon of the seed until it develops leaves
for photosynthesis
Wind/Insect Pollination
Feature Reasonsmall petals, often brown or dull green
no need to attract insects
no scent no need to attract insects
no nectar no need to attract insects
pollen produced in great quantities
because most does not reach another flower
pollen very light and smooth so it can be blown in the wind
anthers loosely attached and dangle out
to release pollen into thewind
stigma hangs outside the flower
to catch the drifting pollen
stigma feathery or net like to catch the drifting pollen
Wind Pollinated Flowers
Feature Reason
large, brightly coloured petals to attract insects
often sweetly scented to attract insects
usually contain nectar to attract insects
moderate quantity of pollen less wastage than with wind pollination
pollen often sticky or spiky to stick to insects
anthers firm and inside flower to brush against insects
stigma inside the flower so that the insect brushes against it
stigma has sticky coating pollen sticks to it
Insect Pollinated Flowers