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Difficulty: MediumReproductive Systems and Processes in Organisms

A field biologist examines a grass species growing in an open savanna and notices that its flowers lack petals and nectaries, but possess long filaments with exposed anthers and large, feathery stigmas. Which of the following best explains the structural adaptation of these feathery stigmas?

  1. They provide a large surface area to efficiently catch light, airborne pollen grains carried by wind currents.Answer
  2. B
    They secrete sweet nectar and strong scents to attract specific insect pollinators from long distances.
  3. C
    They physically trap large, sticky pollen grains transferred by visiting birds during feeding.
  4. D
    They act as protective shields to prevent water loss and self-pollination during heavy rainstorms.

Answer

Feathery stigmas provide a large surface area to efficiently catch light, airborne pollen grains carried by wind currents.
In wind-pollinated (anemophilous) plants such as grasses, feathery stigmas extend outside the flower to form a large, branched surface designed to intercept light, dry pollen grains drifting on air currents.

Step-by-Step Solution

1
Analyze floral characteristics given in the scenario
The absence of colorful petals and nectaries, combined with exposed anthers, indicates wind pollination (anemophily).
Wind-pollinated flowers do not invest energy in petals, scent, or nectar since they rely on air movement rather than animal vectors.
2
Identify the functional role of feathery stigmas in anemophilous plants
Feathery, branching structures extend outside the floral envelope to maximize the likelihood of trapping passing airborne pollen grains.
Because wind carries pollen randomly, a net-like or feathery receptive surface increases capture efficiency.

Key Concept

Floral Adaptations for Wind Pollination (Anemophily)
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Topics

Reproductive Systems and Processes in Organisms

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