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Revision map: plant tissues

Plant tissues are meristematic, cells that divide, or permanent. Permanent tissues are simple (parenchyma, collenchyma, sclerenchyma, epidermis, cork) or complex (xylem and phloem). For each tissue, remember the cells, the place and the job, and watch the pairs that students mix up.

This is the first lesson of Tissues: Revision Sprint, free for everyone to read.

The whole chapter on one table

Plants have two groups of tissue. Meristematic tissue is made of cells that keep dividing. Permanent tissue is made of cells that have stopped dividing and have a fixed job.

Tissue	Cells	Where it is found	Job
Apical meristem	small, dense, thin wall, big nucleus	tips of the root and the shoot	makes the plant longer
Lateral meristem (cambium)	same	the sides of a stem or a root	makes it thicker
Intercalary meristem	same	the base of leaves, near a node	adds length at the base
Parenchyma	living, thin wall, loosely packed	all over the plant	stores food, fills space
Chlorenchyma	parenchyma with chloroplasts	leaves	photosynthesis
Aerenchyma	parenchyma with big air spaces	water plants	helps them float
Collenchyma	living, thick at the corners	leaf stalks, below the epidermis	flexibility and support
Sclerenchyma	dead, very thick wall (lignin)	coconut husk, leaf veins, stems	hardness and strength
Epidermis	flat cells, tightly packed	outer layer of leaves, stems, roots	protection; stomata for gases
Cork	dead cells with suberin	bark of an old tree	waterproof protection
Xylem	tracheids and vessels (dead), parenchyma, fibres	root, stem, leaf	water and minerals up
Phloem	sieve tubes and companion cells (living)	root, stem, leaf	food to all parts

You should find that "dead, thick all over" names sclerenchyma when it carries nothing, but xylem when it carries water. One clue can change the answer, which is exactly how exam questions trap you.

The pairs that students mix up

Collenchyma and sclerenchyma. Collenchyma is alive and thick only at the corners, so it bends. Sclerenchyma is dead and thick everywhere, so it is hard.
Xylem and phloem. Xylem: water and minerals up, mostly dead. Phloem: food to all parts, alive.
Apical and lateral meristem. Apical makes the plant longer; lateral makes it thicker.
Parenchyma and aerenchyma. Aerenchyma is only parenchyma with large air spaces.

What an examiner likes to ask

"Name the tissue that makes a stem thicker." (Lateral meristem, the cambium.)
"Why are the cells of xylem dead?" (An empty tube lets water flow with nothing in the way.)
"Why is a leaf stalk flexible?" (It has collenchyma.)
"What is the job of a stoma?" (It lets gases in and out, and water vapour out.)

Try it in Python

This program shows five clues, and then the answers. Say the tissue to yourself before you look.

Practise with new numbers

Common mistakes

Saying xylem carries food. It carries water and minerals; phloem carries food.
Calling collenchyma dead. It is alive; sclerenchyma is dead.
Putting stomata in cork. Stomata are in the epidermis; cork has no pores.
Mixing up the meristems. Tips: longer. Sides: thicker. Base of a leaf: regrowth.

Remember these

Meristem divides. Permanent tissue has a job.
Collenchyma: alive, thick at the corners. Sclerenchyma: dead, thick everywhere.
Xylem: water and minerals up, mostly dead. Phloem: food everywhere, alive.
Epidermis has stomata. Cork is dead and waterproof.

Check yourself

Try each one on your own first. If you are stuck, open a hint. Then check with Show the answer.

Which tissue makes a tree trunk thicker each year?

Which tissue has dead cells that carry water?

Which tissue lets a leaf stalk bend?

Name two plant tissues whose cells are dead when they do their job.

Liked this lesson? There is more

Tissues: Revision Sprint is a Standard course. It adds 2 more lessons, practice and tests on top of the free chapter.

6Problems2Python Labs1Question Set1Mock Test

Revision map: animal tissues: Animals have four main tissues. Epithelial tissue covers and lines. Connective tissue joins, supports and carries. Muscular tissue contracts. Nervous tissue carries messages. For each tissue, remember the cells, the place and the job, and watch the pairs that students mix up.