Difference between Corm and Bulb

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Plants modify their stems in a variety of ways to suit their adaptation demands. Rhizomes, bulbs, corms, and tubers are underground stems that resemble the roots of plants, but nodes and internodes, leaves, and buds distinguish them. Stems have been adapted by nature to accomplish roles like food storage, plant support, protection, and vegetative growth. Geophytes are the plants that fall within this group. Following a period of vigorous growth, both corms and bulbs require a period of rest. Bulb examples include garlic, while corm examples include crocus, gladiolus, autumn crocus, and so on.

Key takeaways: Corm, Bulb, Roots, Bud, Stems, Food


What is Corm?

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Several plants have a corm, which is a swelling subterranean plant stem modification. During one growing season, Corms are designed to store nutrients and food that the plant can use later. They aid in the production of various plant parts such as roots, leaves, and flowers in preparation for the plant's next growing season.

Cormlets or individual corms are used to reproduce corms. These cormlets can be split from the parent plant to create perfect replicas. The look of corms is flattened or somewhat spherical. Under the earth, roots can sprout from the corm base. The parent corm usually dies back, and the corm lets it become the plant's source the following year. The corm collects nutrients and has membranous to scaly leaves. It preserves them for the following season. For vegetative multiplication, the corm can be separated and moved to various sections of the garden. Classic corm examples include gladiolus, crocus, and crocosmia.

Corm

Corm


What is Bulb?

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Bulb is another stem alteration. This type of stem is found on most perennial monocotyledons, and it serves as a resting place for their seeds. A bulb is characterized by a huge, central bud that grows underground and is usually shaped like a globe. A bud grows from the bulb's center, producing leaves and flowers. It also has fleshy or membrane leaves that grow from a short stem. The bulb base sprouts a clump of adventitious roots. The bulb's branches emerge from the lateral buds. The leaves are where all the plant's food is stored. As the bulbs become older, they are replaced by new bulbs.

Apart from garlic, the onion is the best example of a bulb. Bulb plants include lilies, tulips, and hyacinths. Some bulbs, such as the lily, tulip, and iris, are grown for their decorative blossoms.

Bulb

Bulb

Also Read: Nodes and Internode


Differnce between Corm and Bulb

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The difference between corm and bulb is listed below:

Characteristics

Corm

Bulb

Shape

It may be spherical, elongated or compressed.

It may be spherical or pyriform.

Structure

It usually has a round and swollen stem base with scaly leaves.

It has short stems with a fleshy leaf base.

Type

It is underground stem modification.

It is a condensed shoot that grows underground.

Stem

It is enlarged and swollen. 

It is of conical shape. 

Buds

It is an external bud.

It is an internal bud.

Adventitious root

It is developed all over the stem.

It is developed on the ventral; side. 

Food storage

It is in a stem.

It is in leaf base. 

Tunic

It is absent.

It is present. 

Nodes

Distinct circular nodes are present. 

No clear cut nodes are present. 

Cork

Corm is surrounded by cork. 

Cork is absent. 

Growth and propagation

It is usually on the sides or above the stem. 

New bulbs are replaced by old ones. 


Things to Remember

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  • Corm and bulb are underground stem adaptations that have been developed for food storage and to survive in harsh environments.
  • Corms are swollen underground stems that serve as food storage for the plant while it is dormant.
  • It has a spherical shape with a flattened base, and it grows vertically below ground.
  • An underground stalk with fleshy and scale-like layers encircling a central bud is known as a bulb. 
  • A cluster of adventitious roots makes up the bulb's base. The bulbs' shoots emerge from the lateral buds, and their leaves have the ability to store food. 
  • An apical bud, located in the bulb's center, produces leaves and flowers.

Also Read: 


Sample Question

Ques. What are geophytes? (2 marks)

Ans. Geophytes are plants that have underground storage organs in which they store energy and water. Plants having tubers, bulbs, corms, or rhizomes are also classified as geophytes.

Ques. What are sub-aerial and aerial stems? (2 marks)

Ans. Subaerial stems travel parallel to the ground and produce roots at intervals called nodes. Aerial stems are found above ground and serve a number of purposes such as climbing, protecting, synthesis of food, etc. 

Ques. What are bulbs? (4 marks)

Ans. Another stem alteration is a bulb. This type of stem is found on most perennial monocotyledons, and it serves as a resting place for their seeds. A bulb is characterized by a huge, central bud that grows underground and is usually shaped like a globe. A bud grows from the bulb's centre, producing leaves and flowers. It also has fleshy or membrane leaves that grow from a short stem. The bulb base sprouts a clump of adventitious roots. The bulb's branches emerge from the lateral buds. The leaves are where all the plant's food is stored. As the bulbs become older, they are replaced by new bulbs.

Apart from garlic, the onion is the best example of a bulb. Bulb plants include lilies, tulips, and hyacinths. Some bulbs, such as the lily, tulip, and iris, are grown for their decorative blossoms.

Ques. What are corms? (4 marks)

Ans. Several plants have a corm, which is a swelling subterranean plant stem modification. Corms are designed to store nutrients and food that the plant can use later. During one growing season, these nutrients are usually kept in the corm. They aid in the production of various plant parts such as roots, leaves, and flowers in preparation for the plant's next growing season.

Corms resemble bulbs in appearance, but they vary in that they lack the stratified scales found in bulbs. Cormlets or individual corms are used to reproduce corms. These cormlets can be split from the parent plant to create perfect replicas. The look of corms is flattened or somewhat spherical. Under the earth, roots can sprout from the corm base. The parent corm usually dies back, and the corm lets it become the plant's source the following year. The corm collects nutrients and has membranous to scaly leaves. It preserves them for the following season. For vegetative multiplication, the corm can be separated and moved to various sections of the garden. Classic corm examples include gladiolus, crocus, and crocosmia.

Ques. Write the difference between Corm and bulbs. (5 marks)

Ans. The difference between corm and bulb is listed below:

Characteristics

Corm

Bulb

Shape

It may be spherical, elongated or compressed.

It may be spherical or pyriform.

Structure

It usually has round and swollen stem base with scaly leaves.

It has short stems with fleshy leaf base.

Type

It is underground stem modification.

It is a condensed shoot that grows underground.

Stem

It is enlarged and swollen. 

It is of conical shape. 

Buds

It is an external bud.

It is an internal bud.

Ques. What are the functions of stem? (5 marks)

Ans. Various functions of stem are listed below:
  • It retains leaves, flowers, and fruits in place.
  • The stem permits the leaves to be arranged in such a way that they get direct sunlight, allowing them to perform photosynthesis efficiently. Gas exchange is also possible due to the arrangement and positioning of the leaves.
  • The vascular bundles of stems include xylem and phloem, which transport water and minerals throughout the plant.
  • Stems produce flowers and fruits in such a way that pollination, fertilisation, and seed dispersal are made easier.
  • Some stems are modified in order to store food and water. Succulents, for example.

Ques. How do corms grow and propagate? (5 marks)

Ans. Corms resemble bulbs in appearance, but they vary in that they lack the stratified scales found in bulbs. Cormlets or individual corms are used to reproduce corms. These cormlets can be split from the parent plant to create perfect replicas. The look of corms is flattened or somewhat spherical. Under the earth, roots can sprout from the corm base. The parent corm usually dies back, and the corm lets it become the plant's source the following year. The corm collects nutrients and has membranous to scaly leaves. It preserves them for the following season. For vegetative multiplication, the corm can be separated and moved to various sections of the garden. Classic corm examples include gladiolus, crocus, and crocosmia.

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