proplastid

/proʊˈplæstɪd/
noun
  1. A small, undifferentiated organelle in a plant cell that can develop into various types of plastids, such as chloroplasts.
    • Scientists study proplastids to understand how plants develop green leaves.
    • In the dark, proplastids remain small and colorless until exposed to light.
    • Each new plant cell inherits proplastids from its parent cell.