inoculum

(pl.: inocula) 1. A small piece of tissue cut from callus, or an explant from a tissue or organ, or a small amount of cell material from a suspension culture, transferred into fresh medium for continued growth of the culture. See: minimum inoculum size. 2. Microbial spores or parts (such as mycelium). 3. Vaccine.

Microorganisms produced from a pure culture used to start a new culture in a larger vessel than that in which they were grown.