Question

Write a brief account of the different types of placentations

Answer 1

placentation means arrangement of ovule on the placenta of ovary is called placentation
types of plcentation
1.Marginal placentation-example:pea
ovules are arranged at the margin of ovary
2. Basal-example:sunflower
ovules are present at the base of ovary
3.Axile-example:lemon
ovules are present attached to sepals line
4.Parietal-example:mustard
ovules are arranged on inner wall of ovary
5.Free central -eg:primrose
present freely at centre of ovary

Answer 2

Hello!!

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✓ Marginal placentation

• The ovary in which the placenta forms a ridge along the ventral suture of the ovary and the ovules develop on two separate rows is known to have marginal placentation.

• This type of placentation is found in peas.

✓ Free central placentation

• In free central placentation, the ovules develop on the central axis while the septa are absent.

• This type of placentation is found inDianthus and primrose.

✓ Basal placentation

• The ovary in which the placenta develops from its base and a single ovule is found attached to the base is said to have basal placentation.

• It is found in marigold and sunflower.

✓Parietal placentation

• When the ovules develop on the inner walls of the ovary, the ovary is said to have parietal placentation.

✓ Axile placentation

• In axile placentation, the placenta is axial and ovules are attached to it.

• Examples include China rose, lemon, and tomato.

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Thanks!!