Protoplast wall regeneration—Typical timeframe in nutrient medium After plating viable plant protoplasts on a suitable nutrient medium with osmoticum, approximately how long do they generally take to synthesize and deposit a new cell wall under standard culture conditions?

Introduction / Context:
Once plant protoplasts are isolated, the first milestone toward cell division is the regeneration of the cell wall. Knowing the typical timeframe helps practitioners schedule medium changes, monitor viability, and plan downstream steps like colony formation.

Given Data / Assumptions:

• Healthy, enzyme-released protoplasts are plated in an osmoticum-balanced medium.
• Temperature, pH, and nutrients are appropriate for the species.
• No mechanical stress or contamination.

Concept / Approach:
Wall regeneration involves re-synthesis of cellulose and matrix polysaccharides at the plasma membrane, guided by cytoskeletal elements. Under standard conditions, visible wall deposition and rounding-to-polygonal transition are observed within a few days rather than hours or weeks.

Step-by-Step Solution:

Verification / Alternative check:
Microscopy (anisotropic birefringence, cellulose staining) confirms new wall formation typically in the 2–5 day window for many herbaceous species.

Why Other Options Are Wrong:

• (b)–(d) are longer than usual for initial wall formation and risk culture decline.
• (e) A few hours is too short for robust wall re-assembly in most systems.

Common Pitfalls:
Underestimating the need for correct osmoticum; failure leads to lysis or delayed wall regeneration.

Final Answer:
2–5 days