Flooding-adaptive root and shoot traits in rice.

Area of Science:

• Plant Biology
• Agronomy
• Ecology

Background:

• Flooding severely impacts photosynthesis and respiration in wetland plants like rice (Oryza spp.) due to slow gas diffusion.
• Rice exhibits diverse strategies to cope with soil flooding, partial submergence, and complete submergence.

Approach:

• This review analyzes functional adaptive traits for flood tolerance across molecular, anatomical, physiological, and ecological levels.
• It examines stem elongation and metabolic reduction as key survival mechanisms in different rice varieties.

Key Points:

• Deepwater rice varieties elongate stems to maintain photosynthesis during partial submergence.
• Other varieties conserve carbohydrates via metabolic reduction for regrowth after complete submergence.
• Introgressing flood tolerance traits into high-yielding rice improves cultivars for millions of farmers.

Conclusions:

• Climate change necessitates further improvements in rice flood tolerance, particularly for prolonged complete submergence and stagnant flooding.
• Future breeding should focus on traits like aquatic adventitious roots and enhanced underwater photosynthesis through longer gas film retention.