The cell wall of a young plant cell, the primary wall is capable of growth, which gradually diminishes as the cell matures

“The primary cell wall in plants is capable of growth, which gradually diminishes.”

EXplnation of Lines – From NCERT

🌱 What is the Primary Cell Wall?

The primary cell wall is the first layer of the cell wall that is formed in young, growing plant cells. It is:

• Thin, flexible, and stretchable.
• Composed mainly of cellulose, hemicellulose, pectin, and some proteins.
• Located outside the plasma membrane.

🔁 “Capable of Growth” — What It Means

This refers to the ability of the primary cell wall to expand and stretch as the plant cell grows.

• As water enters the cell (via osmosis), the turgor pressure increases.
• The primary wall loosens and expands, allowing the cell to enlarge.
• Specialized proteins and enzymes (like expansins) help in wall loosening during this phase.

🔸 In essence: The primary wall supports cell enlargement and organ growth in young tissues (like shoot and root tips).

📉 “Which Gradually Diminishes” — What It Means

As the plant cell matures:

• The cell finishes growing in size.
• The primary wall stiffens and thickens.
• A secondary cell wall may be deposited inside the primary wall (in certain cells like xylem).
• The plasticity (ability to stretch) of the primary wall decreases or stops altogether.

🔸 Therefore: The growth ability of the primary wall is temporary, active only during cell expansion, and fades as the cell fully differentiates.

📌 Summary

💬 Clarification

Your doubt:
“so diminish means growth of primary wall instead of wall itself”

SiddSir’s Reply:
Exactly! ✅
When we say: “Growth of the primary cell wall gradually diminishes”
We do not mean that the primary wall itself disappears or reduces.
We mean that:

• 🔹 The ability of the primary wall to support cell expansion — its growth potential — diminishes over time.