Organized Protoplasmic Units of the Plant Cell: I. THEIR OCCURRENCE, ORIGIN, AND STRUCTURE

The development of the placental tissue of the tomato fruit has been investigated and it has been found that the protoplasm of cells of this tissue separates into organized units of protoplasm as the fruit matures and ripens. Similar organized protoplasmic units have been detected in other fruits at a comparable stage of development. A study has been made of the structure and stability of these organized units, and it has been deduced that these organized units of protoplasm are in fact compartments of the protoplasm of the cell which have become separated from one another. Each organized protoplasmic unit is able to exist independently of the cell for several days, and is apparently surrounded by a membrane of the endoplasmic reticulum. The possible significance of these new findings is discussed in relation to the structural and biochemical organization of the plant cell.