Question

Which one increases girth of stem or root?

• A. Xylem
• B. Phloem
• C. Cambium
• D. Cortex

Answer 1

Answer: (C)

Cambium

• The secondary growth in plants occurs due to the cell division in the lateral meristems or secondary meristems that helps to increase the thickness or the girth of the plants.
  
• These lateral meristems are located parallel to the longitudinal axis of the plants (stems or roots).
• In vascular plants, the secondary growth occurs due to the activity of the two lateral meristems- the cork cambium and the vascular cambium.
• In woody plants, the secondary growth produces wood and gives shapes to the plant with a thickened trunk.
• The cork cambium forms the thickened cork cells which protect the surface of the plant and also reduces water loss.
• The vascular cambium is also known as fascicular cambium which develops within the vascular bundles that produce xylem to the inner side and phloem to the outer side.
• So, the correct answer is 'Cambium'.