4.2.3.1 Plant tissues

What are the different tissues in a plant?

Epidermal tissue, palisade mesophyll, spongy mesophyll, xylem, phloem, meristem, guard cells

Where is epidermal tissue found?

Around the whole plant

How is epidermal tissue adapted to do its role?

It’s covered with a waxy cuticle which helps to reduce water loss by evaporation as the waxy cuticle prevents water from moving out

Where is palisade mesophyll tissue found?

Underneath the epidermal tissue

How is palisade mesophyll tissue adapted to do its role?

It has lots of chloroplasts which means photosynthesis can happen rapidly and they are positioned at the top of the leaf so they receive lots of light

Where is spongy mesophyll tissue found?

Underneath the palisade mesophyll

How is spongy mesophyll tissue adapted to do its role?

It has lots of air spaces which allows gases to diffuse in and out of cells

Where is xylem found?

In the roots, stems and leaves

How is xylem adapted to do its role?

It’s made up of dead cells joined together which creates a continuous tube that allows the movement of water and mineral ions from the roots to the stem and leaves where it evaporates and leaves the plant

How is xylem strengthened?

A substance called lignin that also has holes along the tube called bordered pits. Lignin makes it strong and waterproof so water won’t leave except at bordered pits which allow minerals to go to specific places in the plant

Where is phloem found?

In the roots, stems and leaves

How is phloem adapted to do its role?

It has elongated cells with holes in the cell walls and many organelles from the cells are removed so cell sap can move through which allows food substances to be moved in both directions, from the leaves where they are made for use or from storage to parts of the plant that need it

Where is meristem tissue found?

At the tips of shoots and roots

How is meristem tissue adapted to do its role?

It’s able to differentiate into different types of plant cell which allows the plant to grow

What do guard cells do?

Surround the stomata and control the opening and closing of them, depending on the water availability