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Difficulty: MediumMorphological and Physiological Adaptations to Environments

Which of the following adaptive features enables red mangrove plants (*Rhizophora mangle*) to anchor effectively and facilitate gaseous exchange in flooded, oxygen-deficient intertidal mud?

  1. Extensive stilt roots covered with porous lenticelsAnswer
  2. B
    Deep taproot systems containing reduced xylem vessels
  3. C
    Feathery aerial leaves equipped with active hydathodes
  4. D
    Thin cuticles on submerged stems for direct excretion of salts

Answer

Extensive stilt roots covered with porous lenticels provide both mechanical anchorage in unstable intertidal mud and aerating pathways for gaseous exchange.
Red mangroves thrive in soft, muddy, waterlogged intertidal zones. Their stilt (prop) roots loop outward and downward to form a wide base that stabilizes the tree against wave action. The exposed surfaces of these specialized roots possess enlarged pores called lenticels, which take in oxygen during low tide to supply underground tissues.

Step-by-Step Solution

1
Identify the environmental challenges of intertidal mangrove habitats
Unstable, soft mud substrate and severe soil hypoxia (lack of oxygen).
Submerged coastal soil lacks free oxygen for subterranean cellular respiration.
2
Evaluate the structural (morphological) requirement for stability
Prop or stilt roots arching outward from the lower stem provide broad structural support.
Deep taproots cannot survive or penetrate deeply into toxic, anoxic sediments.
3
Evaluate the physiological and morphological requirement for oxygen uptake
Lenticels on aerial parts of stilt roots intake atmospheric oxygen.
Internal air spaces transport oxygen down to the submerged root tips.

Key Concept

Morphological adaptations of halophytic mangrove plants to anaerobic intertidal soils
Estimated Time:1m 0s
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Topics

Morphological and Physiological Adaptations to Environments

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