[Campbell Biology P.892] An etiolated potato plant developing in complete darkness exhibits ... | Practice Question

An etiolated potato plant developing in complete darkness exhibits long, spindly stems and unexpanded, pale leaves. What is the primary adaptive advantage of this morphology in a dark, underground environment?

  • A: To maximize light absorption by increasing surface area, preparing for future photosynthesis.
  • B: To facilitate rapid upward growth, enabling the shoot to reach the soil surface before nutrient reserves are depleted.
  • C: To reduce water loss through transpiration, as water is scarce underground.
  • D: To produce chlorophyll efficiently in anticipation of light exposure.

Explanation

Etiolation is an adaptive strategy for plants growing in darkness e.g., underground . The primary advantage of rapid stem elongation is to quickly push the shoot upwards to break through the soil surface and reach light. Unexpanded, pale leaves and short roots minimize energy waste on structures not yet functional photosynthesis or less needed water absorption in the dark, and they also make soil penetration easier.