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Difficulty: EasyMorphological and Physiological Adaptations to Environments

Epiphytic plants such as tropical orchids grow on the trunks and branches of tall trees high above the forest floor. Which of the following morphological adaptations enables epiphytic orchids to absorb atmospheric moisture directly from humid air and rain?

  1. Spongy velamen tissue covering aerial rootsAnswer
  2. B
    Feathery stigmas protruding outside floral petals
  3. C
    Broad leaves with a high density of exposed stomata
  4. D
    Non-vascular rhizoids anchored deep within ground soil

Answer

Spongy velamen tissue covering aerial roots enables epiphytic orchids to absorb atmospheric moisture directly.
Epiphytic orchids possess an outer dead epidermal layer on their aerial roots known as velamen tissue. This spongy tissue quickly absorbs dew, ambient humidity, and rainwater, storing it for the plant's metabolic needs while preventing desiccation.

Step-by-Step Solution

1
Identify the ecological habitat and challenge of epiphytes
Epiphytes live high in tree canopies without direct access to ground soil or water tables.
Survival depends on capturing airborne moisture, dew, and rain directly from the surrounding air.
2
Evaluate the morphological feature specialized for moisture absorption in aerial environments
Spongy velamen tissue on aerial roots absorbs and retains atmospheric water rapidly.
The multi-layered dead epidermis (velamen) acts like a sponge to take up water during rainfall and humid conditions.

Key Concept

Morphological Adaptations of Epiphytes to Aerial Environments
Estimated Time:45s
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Topics

Morphological and Physiological Adaptations to Environments

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