Question

Secondary growth is absent in -
1. Dicot stem
2. Dicot root
3. Monocot stem
4. Gemnosperms

Answer 1

Correct Answer - Option 3 : Monocot stem

Concept-

• There are two types of growth in the plants- Primary growth and secondary growth.
• Secondary growth
  • Secondary growth results from cell division in the lateral meristems.
  • Due to secondary growth, the stems and roots become thicken.
  • Fascicular vascular cambium and cork cambium are examples of secondary growth.
• Primary growth
  • Primary growth results of cell division at the tips of stems and roots.
  • Primary growth responsible for the increase in the length of plant organs and gives rise to primary tissue.

Explanation-

• Cambium ring is present between xylem and phloem.
• In monocots stem vascular cambium is absent. 
• The vascular cambium is responsible for secondary growth. 

Therefore in monocots' secondary growth is absent. 

• In dicots cambium is present and
• It divides to form secondary xylem and phloem.
• Therefore secondary growth is present in dicots.