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REPRODUCTION
Reproduction in flowering plants
Flowering plants or angiosperms reproduce sexually, Flowering plants have specialized structures called the flowers, which is used for the reproduction process.
HIBISCUS FLOWER
A flower comprises of the following parts PEDICEL
It is a flower stalk attached to the plant. It is where flower develops. If it is branched so as to bear many flowers each branch is called radical.
RECEPTACLE
It is the top of the flower stalk ‘pedicel to which other parts are attached.
CALYX/SEPAL
It is the outermost ring of floral leaves. Are usually great and protect the inner floral structure when the flower is not open. Some species of plants have flowers with rings of sepals. The outermost ring is called the epicalyx
COROLLA
This is a ring of petals on a flower. In some plants the petals are brightly colored. They may fuse to form corolla tube.
STAMEN
This is the male reproductive organs. It consists of filament on top with a head of filament called anther The anther contains pollen grains inside. In the hibiscus flower there are many stamens and filaments which join to forma stamina tube, which is connected to the receptacle.
CARPEL
This is the female reproductive organ, it consists of three parts called ovary, style and stigma - Ovary contains eggs/ stigma.
- Style is a tube connected to the ovary.
Dissection of a Flower
Identify the relevant flower by assessing the floral parts and location of the following in the whole flower:
1. Sepals forming the calyx;
2. Receptacle is the swollen part below the calyx;
3. Flower stalk (pedicel);
4. Petals that form a corolla;
5. Stamens with anthers and filaments; and pistil with stigma, style and ovary.
Dissection to half flower
1. Count the number of sepals, petals and stigma.
2. Cut the flower longitudinally into half and separate it into two halves.
3. Use the hand lens to observe the sepals, styles, petals, stamen, stigma, ovary and the ovules.
Dissection to display carpel
1. Use forceps to cut and make a small opening between the two sepals, then use hand to peel the calyx completely from the flower.
2. Detach the petals by pulling each one downwards towards the receptacle until the entire corolla is removed from the flower.
3. Use forceps to cut and make a small opening at the base of the staminal tube, then expose the ovary with your finger nails by pilling off the staminal tube of the flower around the ovary.
4. Use needle to cut at the base of the staminal tube, then extend the incision to the base of the stigma. Care must be taken not to damage the ovary and the style under it.
5. Repeat the cuttings as much as possible, and then pull apart the strands to completely remove the staminal tube from the flower.
6. Look at the flower you will see stigma, style and ovary collectively known as the carpel.
Observe the ovary, stigma, and style of your flower with a magnifying glass.
Dissection to display stamen
1. Use forceps to cut and make a small opening between the two sepals, then use hand to peel the calyx completely from the flower.
2. Detach the petals by pulling each one downwards towards the receptacle until the entire corolla is removed from the flower.
3. Detach the filament and use the hand lens to observe anther and filament.
