So here we have the pollen grain on the stigma and what happens is they germinate, the tube begins to grow like this. Tend species specific, pollen tube will complete if its the same species.
This diagram we can see the pollen tube all the way down and round to the ovule here coloured yellow.
So, descend through the pollen tube. Moves the nucleus, male nucleus travel down here and into the ovule.
There are number of things will occurred:
Pollen nucleus will fertilise the ovule and the fermentation of a zygote and this in term will grow into the embryo.
The outside of the ovule form the seed coat called "Testa".
The cotyledons is the food stores for the seedling which support plant for their first set of leaves.
Will form fruits from the wall of ovary and carpel.
The transferred of the pollen grain from the anther to the stigma through air carry by the wind.
Pollen grains first adaptations is to have light weight, wings features which allowed to move through the air more efficently. Secondly we were expect to find the anther will hang well clear, anther will expose to the wimnd.
Third feature which related to the stigma, we would expect the stigma has large surface area a kind of feather like structure to catch the pollen grain.
They pass through the air on the wind wich will be caught on the stigma structure here.
If we look at the image here f the grass no colour, no scent, no nectaries and no point of producing sugar which is the waste of energy for the grass which the wind that pollinated the plant and the adaptaions are light pollen grain, exposed anthers and exposed stigma.
In the process of pollinating of flower, there must be a transferred of pollen grains from the anther of one plant to the stigma of another.
Pollen is the small structure which contain the male nucleus and the transferred in an insect pollinated plant is take places by insects.
So, its necessary for this type of flower to attract insect into the first flower and then have a reason to go to the second flower. If pollen goes to one plant to another we called it cross-pollination.
Looking the single flower structure we found the adaptations to attract the insect, first of all we might call signals which is in the inside which is colour petals, insect can see colours.
Second thing are scents which flowers has which attract the insect so, insect can detect these molecules and be attract by the plants from the scents.
A value to the inside of going into the flower which provide food which at the nectaries is producing a sugar called fructose, many insect will use the pollen itself to as a source of protein and the stamen is the male part of the plant and compose to the anther which is produce pollen grains and their on the stalk called the filament.
So, the anther and the filament form the stamen and then the female is compose of 3 sections which are the stigma which pollen grains fall, style which connects to the stigma to the ovary which we can find the eggs called the ovules and this whole structure here is called a carpel that the female part and the stamen of the stamen.
