[Campbell Biology P.919] Plants that have acclimated to drought stress are often more resist... | Practice Question

Plants that have acclimated to drought stress are often more resistant to freezing stress as well. Which of the following is the most likely reason for this increased resistance?

  • A: Both stresses promote the formation of air tubes for oxygen supply.
  • B: Acclimation to drought leads to increased production of auxins, which enhance overall plant vigor.
  • C: Both stresses induce the synthesis of solutes that help maintain water balance and membrane fluidity.
  • D: Drought acclimation primarily involves root growth, which indirectly strengthens the plant against cold.

Explanation

The provided table on 'Environmental Stress' shows that for 'Salt' stress, the major response is 'Avoiding osmotic water loss by producing solutes tolerated at high concentrations.' For 'Cold' stress, the responses include 'Adjusting membrane fluidity; avoiding osmotic water loss; producing antifreeze proteins.' Drought stress also involves osmotic challenges. Both cold and drought/salt stress induce the plant to synthesize various protective solutes like sugars, amino acids, and polyols that act as osmolytes or cryoprotectants. These solutes help maintain cell turgor and protect cellular structures, including membranes, from damage due to water loss or ice crystal formation, thus providing cross-resistance.