If the cork cambium is not immortal, how is that the outer coverings of the trees (the cork) is maintained over time?
The maintenance of the outer coverings of trees, such as the cork, is facilitated by the continuous activity of the cork cambium. While the cork cambium is not immortal and can eventually become inactive or die off, it plays a crucial role in the long-term maintenance of the tree's outer protective layers.
To understand how the cork is sustained over time, we need to look at the structure and function of the cork cambium. The cork cambium is a layer of actively dividing cells found in the bark of trees. It is responsible for producing new cells both inwardly (towards the tree's inner layers) and outwardly (towards the outer surface).
When the cork cambium divides inwardly, it produces secondary phloem, which forms a part of the inner bark. This tissue helps transport nutrients from the leaves to different parts of the tree. However, the outer division of the cork cambium is what leads to the formation of new cork cells.
As the cork cambium produces new cork cells, the older ones get pushed towards the outer surface, forming a protective layer known as the periderm. These outer layers of cork cells are impregnated with a substance called suberin, making them impermeable to water, gases, and potential pathogens. This contributes to the durability and resistance of the cork.
While the cork cambium itself may not be immortal, it is capable of forming a new layer of cork cambium cells, known as the phellogen, right beneath the old cork layer. This allows for the continuous production of new cork cells, which replace the old ones as they get sloughed off, worn out, or damaged over time.
In summary, the maintenance of the outer coverings of trees, such as the cork, is sustained by the continuous activity of the cork cambium. Although the cork cambium is not immortal, it produces new cork cells that gradually replace older ones, ensuring the tree's outer protective layers are maintained.