Growing thicker
The lateral meristem increases girth.
A thick trunk
A tree trunk is much thicker than the thin stem of the small plant it grew from.
Where do you think the extra thickness comes from?
What this lesson covers
The idea
The lateral meristem is a ring of actively dividing cells in the stem that produce new cells inside and outside in a concentric manner, increasing the stem's girth.
A thick trunk
A tree trunk is much thicker than the thin stem of the small plant it grew from.
Where do you think the extra thickness comes from?
- From a ring of dividing cells in the stem
- From the stem stretching like rubber
- From the leaves pressing on it
Look inside the stem
Let time pass, then switch on the ring of dividing cells.
A ring that adds layers
Inside the stem there is a ring of cells that keep dividing. They make new cells on both sides of the ring, inside and outside, layer upon layer like circles around a centre. The stem becomes thicker. This ring is the lateral meristem.
The lateral meristem is a ring of actively dividing cells in the stem. It produces new cells inside and outside in a concentric manner, increasing the stem's girth.
Notes
The lateral meristem is a ring of dividing cells that adds new cells inside and outside and so increases the stem's girth.
Check yourself
Which meristem increases the girth of a stem?
Where does the lateral meristem put its new cells?
How are the dividing cells of the lateral meristem arranged in the stem?
What does girth mean?
- The apical meristem. Apical meristems at the tips make the plant grow in length.
- The intercalary meristem. The intercalary meristem helps a plant regrow after it is cut or grazed.
- The lateral meristem — correct. Yes!
- Both inside and outside the ring — correct. Yes!
- At the tip of the stem. Growth at the tip is done by the apical meristem. The ring adds cells on both of its sides.
- Outside the ring, and none inside. The cells of the ring produce new cells both inside and outside.
- In a single line down the middle. The dividing cells are arranged in a ring in the stem, not in a line.
- In a ring — correct. Yes!
- In a patch at the root tip. The root tip has an apical meristem. The lateral meristem is a ring in the stem.
- The height of the stem. Height is the length of the stem. Girth is its thickness.
- The depth of the roots. Depth of the roots is part of growth in length. Girth is the thickness of the stem.
- The thickness of the stem — correct. Yes!