Question

The stem of submerged hydrophytes is soft and weak due to:

• A. Absence of xylem
• B. Absence of aerenchyma
• C. Absence of phloem
• D. Reduced mechanical tissue and xylem

Answer 1

The correct option is D Reduced mechanical tissue and xylem

The stem of submerged hydrophytes is soft and weak due to reduced or poorly developed mechanical tissue and xylem. The mechanical tissues that provide strength to the stem are collenchyma, sclerenchyma and xylem fibres. These are poorly developed in hydrophytes.

Xylem and phloem are conducting tissues of plants. Xylem conducts water ann minerals while phloem conducts the photosynthetic byproducts. Abesnce of these two will make survival impossible for angiosperms. So, they will die.

Aerenchyma are parenchymatous cells with large air spaces which provide buoyancy and help the plant to float in water. In its absence the plants will sink and die.