Modified stems have been altered by the parent plant to fit the needs of the plant. There are three examples I will be stating here.
First, there are the stolon. They grow horizontally along the ground and they grow above the ground. An example would be strawberries.
Next, there are the tuber stems. They are enlarged underground stems that are for starch storage. An example of this would be potatoes.
Finally, there are the succulent stems. They are fleshy and often leafless. They are used for water storage. An example would be cacti.
The modified stem used for energy storage is a tuber, such as a potato or sweet potato. Tuberous stems become swollen with stored food reserves such as starch, making them an ideal structure for storing energy.
Roots and stem get modified for storage or performing any specific function such as climbing or overcoming hostile environmental conditions. The basic difference between a root and stem is that in case of root, the primary vascular bundles are radial whereas in stems these are conjoint and collateral.
A rhizome stores its food reserve in the form of starch in specialized storage cells called parenchyma cells located in the enlarged underground stem structure.
No, onions are not an example of plants with modified roots. Onions have a bulb which is a modified stem, not modified roots. Examples of plants with modified roots include carrot and radish.
Stems store food in the form of starch or other carbohydrates in specialized cells called parenchyma cells. These cells act as storage reservoirs to provide energy for growth and support during times of need, such as winter or periods of drought. The stored food can later be mobilized and transported to other parts of the plant as needed.
Tuber is the modified organ of the plant potato.
The modified stem used for energy storage is a tuber, such as a potato or sweet potato. Tuberous stems become swollen with stored food reserves such as starch, making them an ideal structure for storing energy.
A portion of a root swells for food or water storage, e.g. sweet potato. A type of storage root distinct from taproot.
tuber
A rhizome is a long modified stem that grows beneath the ground horizontally. It is often found in plants such as ginger, bamboo, and irises, and serves as a storage organ for nutrients and water.
roots modified for food storage
Onion is a modified stem because it is a stem which grows underground
Water chestnut is a type of aquatic vegetable plant that produces underwater tubers, which are a form of modified stem. The tubers grow underwater and serve as a storage organ for the plant.
Sugar cane is not called a stem tuber because it does not develop underground like traditional tubers such as potatoes. Instead, sugar cane stores food in its above-ground stem through the process of photosynthesis. The stem of sugar cane is thick and fibrous, allowing it to store significant amounts of sugar produced during photosynthesis. This distinguishes it from stem tubers, which are modified underground stems used for food storage.
This type of modification of stem for storage of food is called bulb. The stem is extremely condensed in the form of a disc and is surrounded by fleshy scales. Since the scales (modified leaves) do not resort to photosynthesis, the bulb remains underground to overcome adverse atmospheric conditions of summers.
Modified Stem
A onion is a modified stem