Rice physiology — survival in submerged paddy fields Why can rice plants grow successfully in water-submerged soils typical of paddy cultivation?

Introduction / Context:
Flooded paddy soils are hypoxic or anoxic, yet rice thrives where many crops fail. The plant has multiple anatomical and physiological strategies that maintain root function, gas exchange, and tolerance to reduced soil chemistry.

Given Data / Assumptions:

• Environment: waterlogged, oxygen-poor soils.
• Species: Oryza sativa (rice).
• Mechanisms may include morphology, oxygen transport, and detoxification.

Concept / Approach:

Rice develops aerenchyma (air spaces) in roots and shoots, facilitating internal oxygen diffusion from shoots to roots. Oxygen release at root tips and along the cortex forms an oxidized rhizosphere that can precipitate toxic reduced ions (like Fe2+) as less soluble oxides, mitigating toxicity. Rice also expresses enzymes and transporters aiding tolerance to sulfides and other reduced compounds common in flooded soils.

Step-by-Step Solution:

Verification / Alternative check:

Agronomy and plant physiology studies document each mechanism, explaining rice’s comparative advantage in waterlogged cultivation systems.

Why Other Options Are Wrong:

Each single mechanism alone is incomplete; rice employs all of them together. “None of the above” contradicts well-established adaptations.

Common Pitfalls:

Focusing exclusively on aerenchyma while overlooking oxidized rhizospheres and detoxification strategies that enable longer-term survival and productivity.

Final Answer:

All of the above