yes , because sem machine check the samples in nano meter range and give result it does not relaterd to the time period of the material

Hello Thank you for your reply.

Therefore I should just go ahead and dehydrate my samples with increasing concentration of EtOH and apply critical point drying etc?

conductivity is also involved, as if your sample is non conductor, then its difficult to get clear image.

I think no problem. You can preserve.

sem clear the morphology of the material so I think go ahead

Yes ethanol is used as good preservative. It is also used to prepared sample before SEM and also able to clear the image. Go head.

As the key here is to prevent hornification/shrinkage of tissular material and cellullose/starch/lignin/etc (whatever is present in your roots depending on the plant/wood species), 50% EtOH should be OK to prevent dehydration and preserve your root samples for some time.

Of course, you'd have to prepare a new sample from the same source regularly and observe it to be sure it does not evolve and thus determine the storage time that is not to be exceeded.

Then, do indeed proceed with graded EtOH solvent replacement before dry cutting or embedding for SEM.

I'm not that familiar with plant material but cellulose fibers and wood pulp are pretty well preserved that way. An alternative would be to freeze-dry your roots before transportation but I guess it's more practical to just put the root block in a EtOH container when sampling onsite ?

Hello Pierre, thank you for the suggestion but yes it is certainly more practical to just preserve with EtOH for my case. I will be further dehydrating my samples which are in 50% EtOH for 4 months.. I will see how much artefacts there will be.

Thank you everyone else for your kind answers!