Which structure in plant cells is primarily responsible for storage?

The vacuole is primarily responsible for storage in plant cells. It serves several vital functions, one of which is to store nutrients, waste products, and other substances necessary for the cell's functioning. In many plant cells, the vacuole is large and can occupy a significant portion of the cell's interior. This storage capability helps maintain turgor pressure, which is essential for keeping the plant upright and contributing to its overall structure.

The chloroplast, while crucial for photosynthesis, is not involved in storage; instead, it focuses on energy production. The thylakoid is a component within the chloroplasts where the light-dependent reactions of photosynthesis occur. The nucleus functions primarily as the control center of the cell, housing the genetic material and coordinating activities like growth, metabolism, and reproduction, rather than storage. Hence, the vacuole stands out as the structure dedicated to storage in plant cells.