ergastic

/ɜrˈɡæstɪk/
adjective
  1. Relating to or denoting non-living substances or materials produced by a plant cell, such as starch, oils, or crystals.
    • The ergastic substances in the potato cell include starch grains.
    • Under the microscope, the ergastic materials appeared as bright crystals.
    • Plant cells store ergastic products like oils and resins for later use.