Collenchyma tissue differs fundamentally from sclerenchyma tissue in which of the following cytological characteristics?

Answer and explanation

Correct answer: C. Collenchyma has living cells with pectin thickenings; sclerenchyma has dead lignified cells

  1. Step 1: Collenchyma is a simple living mechanical tissue found below the epidermis (hypodermis) in young dicot stems and petioles.
  2. Step 2: Its cells remain living at maturity, retain functional protoplasts, and exhibit cell wall thickenings concentrated at corners composed of cellulose, hemicellulose, and hydrophilic pectin.
  3. Step 3: Sclerenchyma consists of elongated fibers or sclereids that deposit thick, rigid secondary walls impregnated with hydrophobic lignin and die at maturity, losing their protoplasm.
Answer
Collenchyma consists of living cells with localized cell wall thickenings of cellulose, hemicellulose, and pectin, while sclerenchyma consists of dead cells with uniformly lignified secondary walls
Why not the others: 'Collenchyma cells are completely dead...' reverses the living/dead status of both tissues; 'Collenchyma possesses heavily suberized cell walls...' confuses pectin with suberin (found in cork cells); 'Collenchyma occurs exclusively in deep wood tissues...' is geographically and taxonomically false, as collenchyma is absent from monocots and wood.

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