- A Plants regulate mineral uptake so closely and consistently that the amount absorbed matches the amount required for optimal growth across most soil and seasonal conditions
- B Plants absorb minerals in excess of what is needed for optimal growth when soil levels are high; excess can disrupt ion balance and cause toxicity
- C Plants actively exclude most mineral ions beyond their immediate metabolic needs through selective root membrane transport
- D Luxury consumption of minerals tends to improve overall plant growth rate and final crop yield in most field conditions
Correct answer: B. Plants absorb minerals in excess of what is needed for optimal growth when soil levels are high; excess can disrupt ion balance and cause toxicity
Explanation: Luxury consumption occurs when plants absorb minerals in excess of metabolic needs (especially K, N, P). While temporarily tolerated (stored in vacuoles), extreme excess causes ionic imbalances, osmotic effects, and toxicity. Excess nitrogen causes excessive vegetative growth at the expense of reproduction.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.