Difference between modified stem and modified leaf in bulbs.

In bulbs like onions, both stem and leaf undergo modification but perform different roles. The stem portion is short and flattened into a basal plate, from which roots arise below and leaves emerge above. It serves as the attachment and growth center. 

The leaves, on the other hand, are modified into fleshy scales that store food and water. Outer scales dry up to form a papery protective covering. Thus, the stem provides structural support and connection to roots, while the modified leaves act as storage organs.

This division of labor helps the bulb survive underground during dormant seasons and regrow rapidly when favorable conditions return. In simple terms, the stem = base of the bulb, and the leaves = layered storage tissues, both contributing to the plant’s survival strategy.