The Plant Ontology describes structures that exist both "in vivo" and "in vitro". For the past year or so, “in vitro plant structure” (PO:0000004) was defined as “A plant structure that was derived from part of a plant and involves microbe-free growth in a sterile environment”
Recently, we revisited this class and decided it would be better to have the in vitro terms be is_a children of their respective plant structure parents (plant cell, tissue, whole plant, etc) and use a participates_in relationship to an imported term such as "in_vitro growth"
We would like to request the term "in_vitro” or "in_vitro growth" . I have done a pretty thorough search of the OBO ontologies and not found it, although it is used in MESH and the NCI Thesaurus.
I would suggest: is_a “growth quality of occurrent”
Suggested definition: A growth quality of occurrent in which the growth of an organism, structure or group of organisms involves microbe-free growth in a sterile environment.
There are various definitions of in vitro available and the direct translation from Latin means "under glass or within glass". (Of course, this has a historical connotation, most in vitro work now is done in plastics).