Organisms regenerate through various processes, often initiated by the formation of a specialized mass of dividing cells at the injury site.
Regeneration is the process where organisms regrow damaged or missing body parts. The mechanisms differ between plants and animals.
Regeneration Mechanisms
The general process of regeneration is highlighted in the table below:
| Organism Type | Initial Regeneration Structure | Process | Outcome |
|---|---|---|---|
| Plants | Callus | Undifferentiated dividing cells including stem cells form at the injury site and differentiate into new tissues. | New leaves, flowers, stems, or roots develop from the callus. |
| Animals | Blastema | Undifferentiated dividing cells including adult stem cells form at the injury site and differentiate into new tissues. | Regrowth of the missing or damaged body part, like a limb in salamanders. |
Plant Regeneration: Callus Formation
In plants, regeneration often starts with the formation of a callus, which is a mass of undifferentiated cells. According to references, this structure consists of many types of dividing cells, including stem cells. These cells then differentiate to form new plant structures. For example:
- A cut stem can form a callus at the cut end.
- The callus can differentiate into roots, allowing the stem to grow into a new plant.
Animal Regeneration: Blastema Formation
Certain animals, such as salamanders, employ a different structure called a blastema. This is also a mass of dividing cells, including adult stem cells, that forms at the site of injury. From here, these cells differentiate into the cells required for regrowth.
- A salamander can regenerate a lost limb.
- The blastema forms at the stump of the lost limb.
- The blastema cells differentiate into bone, muscle, and skin cells to regenerate the limb.
