Q.Why is the placentation in tomato said to be axile?

Placentation Types – From Intuition to Precision

Think of the ovary as a room where seeds are going to be made. The ovules are the raw material — the future seeds. Placentation is simply the arrangement of these ovules inside the ovary. Where are they attached? How are they placed? That's all.

Why does it matter? Because this arrangement is remarkably consistent within a plant family. If you cut open a flower's ovary and see how the ovules sit, you can often name the family. It's a powerful identification tool.

The Five Types

Let's build each one from a mental picture.

1. Marginal Placentation

Imagine a single long sofa against one wall of a room. The ovules sit along the edge of that sofa — the margin of the carpel. This is the simplest type: one chamber, one line of attachment.

2. Axile Placentation

Now picture a multi-room apartment. The ovules are attached to the central pillar — the axis — where all the walls meet. The ovary is divided into chambers (locules), and ovules sit in the centre of each chamber, on the central column.

3. Parietal Placentation

Imagine the ovules attached to the outer wall of the ovary, not the centre. The ovary may be one-chambered, or it may have false partitions. The key: ovules are on the periphery, not the axis.

4. Free Central Placentation

Here, the ovules sit on a central column that rises from the base of the ovary — but this column is not connected to the ovary wall by any partitions. It stands free. The ovary is one-chambered.

5. Basal Placentation

The simplest of all: a single ovule (or a small group) sits at the very base of the ovary. No fancy arrangement — just one seed at the bottom.

How to Identify in an Exam

When you see a diagram or a real flower:

1. Count the chambers. One chamber? You're looking at marginal, parietal, free central, or basal. Multiple chambers? Axile.
2. If one chamber: Where are the ovules? …