Question

Which one of the following is an edible stem?
a. Ginger
b. Potato
c. Carrot
d. Apple

Answer 1

Hint: Stem tuber is a type of modification of stem that is for storage of excess food as a reserve material by the plant. Thus, tuber is an edible part of the stem and its popular example is potato. The potato is a tuber which is a rich source of starch and many other carbohydrates.

Complete answer:
> The potato has all the parts of a normal stem having nodes and internodes like a stem tuber. Potato can form buds that can develop into new plants by asexual reproduction. It is grown underground. Since, it has reserve food material; it is an edible stem part which is commonly used as a source of carbohydrate.

> Ginger is also a type of stem modification which grows underground and is called rhizome. Rhizomes develop from axillary buds and grow horizontally. These rhizomes are modified plant stems that produce roots and shoot from its nodes.

> Carrot is a type of modification of roots for storage of food. Basically it is a type of tap root which is used as a storage source of reserve food materials. It also grows underground for protection from plant eating animals. It is a storage house of water and starch.

> Whereas last but not the least, apple is a pome fruit. Pomes are the fruits that have a core of several small seeds that are surrounded by a tough membrane. An edible layer of flesh surrounds the fruit from outside.

Hence, The correct answer is, option (B).

Additional information:
A stem tuber is produced from thickened rhizomes. The topmost area of the tuber produces shoots that grow into stems and leaves and the lower part produces roots. These are formed at the side of the parent plant and are located near the soil surface. The main function of the tubers is reproduction and saving food. Under favorable conditions, the parts of the stem which is attached to the main stem dies in autumn or winter season. These tubers remain in soil and produce shoots from their buds in spring season.

Note: Various plants are known to have modified plant parts like roots for storage and functions into tuber or rhizomes; stems for storage, support, structure into aerial, non aerial and underground ; leaves into leaf hook, leaf spine, leaf tendril, leaf bladder etc. to adapt better to the environment.