What does subline mean?

Answer 1

The definition of "subline" (a term relating to cellular Biology) may be found at:

http://www.merriam-webster.com/dictionary/subline

I am answering here in case you meant "sublime"

"Sublime" is a term in chemistry and physics referring to the process in which some materials, given appropriate conditions of temperature and pressure, can change phase directly from a solid to a gas (where most materials under most conditions must pass through the liquid phase when changing from a solid to a gas).

Examples are Iodine, which can sublime at room temperature and pressure (note this refers to pure Iodine, not the solution you buy at the drug store), and ordinary water ice, which can sublime under some temperature and pressure conditions, including in a self-defrosting freezer.