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Difficulty: MediumMorphological and Physiological Adaptations to Environments

Floating hydrophytes, such as Water Hyacinth (*Eichhornia crassipes*), thrive in aquatic environments where support from water and efficient gaseous exchange are essential. Which of the following morphological adaptations enables these plants to maintain buoyancy and exchange gases in stagnant water?

  1. A
    Extensively developed, heavily lignified xylem vessels throughout the root and stem system
  2. Abundant aerenchyma tissue containing spacious intercellular air cavitiesAnswer
  3. C
    Suberized waterproof cuticles surrounding all submerged root epidermal cells
  4. D
    Feathery stigmas and light smooth pollen grains adapted for wind-assisted underwater fertilization

Answer

The presence of abundant aerenchyma tissue with large intercellular air spaces allows floating hydrophytes to remain buoyant and efficiently store and transport gases within their tissues.
The correct answer highlights abundant aerenchyma tissue containing spacious intercellular air cavities. In floating hydrophytes like water hyacinth, aerenchyma reduces overall plant density to keep the plant afloat at the water surface for light absorption and provides internal channels for oxygen diffusion.

Step-by-Step Solution

1
Analyze environmental challenges of floating hydrophytes
Hydrophytes live surrounded by water, requiring buoyancy to remain at the surface for sunlight and special adaptations to supply oxygen to tissues in hypoxic water.
Water provides physical support, eliminating the need for rigid structural tissues.
2
Identify the key morphological tissue modification in aquatic plants
Spongy parenchyma with large air cavities (aerenchyma) trapped in stems and petioles provides buoyancy and aids internal gas exchange.
Air spaces decrease overall plant density while serving as internal oxygen reservoirs.

Key Concept

Morphological Adaptations of Hydrophytes
Estimated Time:1m 0s
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Topics

Morphological and Physiological Adaptations to Environments

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