Tissues that hold a plant up

Three simple permanent tissues hold a plant up: parenchyma, collenchyma and sclerenchyma. Sound-alike hooks help:

• Parenchyma sounds like parents: it stores food for the family.
• Collenchyma sounds like a collar: firm, but it bends.
• Sclerenchyma: think of something hard, like a skull or a nutshell.

Parenchyma cells are living, have thin walls, and are loosely packed with spaces between them. They store food, and in green parts they make food by photosynthesis. In water plants like the lotus, parenchyma has big air spaces that help the plant float.

Collenchyma cells are living, but their corners are thickened with pectin, a substance that makes them a bit rubbery. They give support with flexibility, so stems and tendrils can bend without breaking.

Sclerenchyma cells have thick walls hardened with lignin, and most of them are dead. They are hard and strong, like wood. You find them in stems, in leaf veins, and in the hard coverings of seeds and nuts: the coconut husk and the walnut shell.

Use them to explain what you see:

• Coconut husk fibres are tough: sclerenchyma.
• Coriander (dhaniya) stalks are soft and bendy: living, thin-walled tissue.
• A young mango stem bends in the wind without snapping: collenchyma. If it were sclerenchyma, it would be stiff and could snap.