What is lignification?

[DesertSun]

And how does it show in a cactus? I read this on a member's post, never heard this term before.
Thank you!

[ElieEstephane]

i believe i'm the one that mentioned it. Lignification (i believe i used the french term, in English it should be corking (?) ) is when the cells of a plant absorb lignin and take a woody appearance. This way, a stem will become more rigid, resistant to water and decomposition. Normally woody cells occur either at the base of a stem or at a joint and serve as support. This is the natural case (not a bad thing at all). However, it can happen too when a cactus is too humid (but not rotting). The base will become more and more "woody" to reduce the effect of the humidity on the base. I see that a lot on outside cacti that receive a lot of rain during winter.
Here is an example (photo is not mine):

hh.jpg (143.5 KiB) Viewed 824 times

notice how the stone mulch will retain the humidity in the organic soil and lead to this or rot.

[greenknight]

Lignification is the scientific term for plant tissue becoming woody - the plant adds lignin to the cell walls, which makes them harder and more rigid.

[DesertSun]

Thank you very much for your answers @Elie and @greenknight! So interesting to know, I had heard of corking before, but not this term. It's nice to get to learn new things about cacti!