Vacuolar Protein Bodies in Tomato Leaf Cells and their Relationship to Storage of Chymotrypsin Inhibitor I Protein

Electron microscopy of leaves of tomato has shown that tissue containing chymotrypsin inhibitor I protein has protein in the cell vacuoles. The vacuolar protein was found either as many small bodies or as few large bodies. The data indicate that the vacuole is a temporary storage site for protein which may play an important role in growth and development of the plant. This strongly suggests that the plant-cell vacuole is something more than a site for terminal deposition of waste products. The system offers an unusual opportunity to study the biochemistry and ultrastructure of synthesis, vacuolar deposition, and recall of a well-characterized plant protein.