The Question is from neet-botany morphology-of-flowering-polants , and it was created by the author B VENKAT

Question

In a dicot stem undergoing secondary growth, which tissue is primarily responsible for the increase in girth?

B VENKAT · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
 **Primary Concept**: Secondary growth in dicot stems
 **Related Topics**: Vascular cambium, cork cambium, apical meristem, intercalary meristem, girth increase
 **Prerequisites**: Understanding of plant tissues and their functions, knowledge of meristematic tissues and their roles in plant growth.
## SOLUTION PATHWAY
**Given Information**:
  Dicot stem undergoing secondary growth.
  Question asks about the tissue responsible for girth increase.
**Method & Steps**:
 1. Identify the tissues involved in secondary growth in dicot stems.
  Reasoning: Secondary growth is responsible for increase in girth (diameter) of the stem.  This growth is primarily due to the activity of lateral meristems.
 2. Determine which lateral meristem is responsible for girth increase.
  Working:  The vascular cambium is a lateral meristem that produces secondary xylem (towards the inside) and secondary phloem (towards the outside). This addition of secondary vascular tissues leads to an increase in stem girth. The cork cambium is also a lateral meristem, but it's primarily responsible for the production of periderm (protective outer bark), not directly contributing to the significant increase in girth as the vascular cambium does.
  Key Point: Apical meristems are responsible for primary growth (increase in length), while intercalary meristems are found in grasses and contribute to the elongation of internodes.
 3. Conclude the tissue responsible for the increase in girth.
  Result: The vascular cambium is primarily responsible for the increase in girth of a dicot stem during secondary growth.
  Verification: The significant increase in diameter comes from the accumulation of secondary xylem and phloem produced by the vascular cambium.  The cork cambium contributes to the outer bark but not the main girth increase.
 ## OPTION ANALYSIS
A :x: Cork Cambium: The cork cambium contributes to the formation of the periderm (outer bark), but it does not primarily cause the increase in girth.
B ✓: Vascular Cambium: The vascular cambium produces secondary xylem and phloem, resulting in a significant increase in the stem's diameter.
C :x: Apical Meristem: Apical meristems are responsible for primary growth (lengthening) at the tips of shoots and roots, not secondary growth (girth increase).
D :x: Intercalary Meristem: Intercalary meristems are found in grasses and contribute to the elongation of internodes, not the secondary growth of dicot stems.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing apical and lateral meristems: Remember apical meristems cause primary growth (length), while lateral meristems (vascular and cork cambium) cause secondary growth (girth).
  2.Overlooking the role of vascular cambium: Focus on the significant contribution of secondary xylem and phloem to girth increase.
 **Quick Tips**:
  1.Remember the acronym 'VC' for Vascular Cambium and its role in girth increase.
  2.Visualize the concentric rings of secondary xylem in a dicot stem cross-section.

B VENKAT · Answer

Cork Cambium

B VENKAT · Answer

The correct Option is "Vascular Cambium"

B VENKAT · Answer

Apical Meristem

B VENKAT · Answer

Intercalary Meristem

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