Multiple choice

Which of the following contributes to the thickness of phloem fibres?

  1. Cutin

  2. Lignin

  3. Pectin

  4. Suberin

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phloem fibres, or bast fibres, are composed of sclerenchyma cells which have thick secondary walls. These walls are heavily impregnated with lignin, a complex polymer that provides rigidity and strength to the tissue.