Growing from the tips
Apical meristems make roots and shoots longer.
A root grows deeper
A small seedling grows into a tall tree, and its roots go deep into the soil.
Where on a root do you think the growing happens?
What this lesson covers
The idea
Apical meristems are growth zones of continuously dividing cells at the tips of roots and shoots that make the plant grow in length.
A root grows deeper
A small seedling grows into a tall tree, and its roots go deep into the soil.
Where on a root do you think the growing happens?
- At the tip
- All along the root at once
- Near the soil surface
Watch the tips
Let time pass, then switch on the dividing cells.
Growth zones at the tips
Roots grow from their tips, and the tips are full of dividing cells. Shoot tips also have actively dividing cells. These growth zones are called apical meristems. Their cells keep dividing, so the plant grows longer.
Apical meristems are growth zones of continuously dividing cells at the tips of roots and shoots. They make the plant grow in length.
Notes
Apical meristems at the tips of roots and shoots keep dividing and make the plant grow in length.
Check yourself
Where are the apical meristems found?
In Chapter 2 you saw cells dividing in onion root tips. What does this show?
What kind of cells does a shoot tip contain?
Which tissue makes the stem of a young plant grow taller?
- In a ring around the stem. A ring of dividing cells in the stem is the lateral meristem, which increases girth.
- At the tips of roots and shoots — correct. Yes!
- At the base of an internode. That is where the intercalary meristem is. It lets plants regrow after cutting or grazing.
- Roots grow from the middle. Roots grow from their tips, where the cells divide continuously.
- Roots do not grow in length. Roots do grow in length, from their tips.
- Root tips contain actively dividing cells — correct. Yes!
- Actively dividing cells — correct. Yes!
- Dead cells with hard walls. Dead cells with hard walls cannot divide. Shoot tips contain dividing cells.
- Cells that have stopped dividing and only store food. The cells at a shoot tip are dividing actively, which helps the shoot grow in length.
- The lateral meristem. The lateral meristem increases girth, the thickness of the stem.
- The apical meristem at the shoot tip — correct. Yes!
- The epidermis. The epidermis is the outer protective layer. It is not a growth zone.