Question

What will happen if cork is not formed in older stems and roots?

Answer 1

The cork, part of the plant cambium, has a very important role of protection on trees against parasites and adverse environmental effects. The cork is made up of dead cells that act like the skin on our body-as a mechanical barrier. An important character of the cork is that it is water and gas resistant. 
Therefore the following would occur if cork fails to form in older stems and roots:
-The stems and roots would be subjected to dehydration because the cork, being water resistant, usually protects the plants from loss of water.
-These stems would be predisposed to many disease as they will be vulnerable to attack by parasites.
-The food supply in the stems and roots would be easily accessible to parasitic organisms.

Answer 2

Answer: if the formation of cork does not occur in the older stem, then the outer tissue will rupture due to the increase in girth and plants will get infected by the disease.