Phosphorus Deficiency Affects Memory-Mediated Recovery From Recurrent Water Stress in Drought-Sensitive Soybean

Area of Science:

• Agricultural Science
• Plant Physiology
• Agronomy

Background:

• Phosphorus (P) deficiency and water deficit significantly limit soybean yield globally.
• The interaction between P deficiency and water stress recovery in soybean remains poorly understood.

Purpose of the Study:

• To investigate how P deficiency affects the recovery of soybean plants from recurrent water stress during the grain-filling stage.
• To compare the responses of two soybean cultivars with differing drought sensitivities.

Main Methods:

• Soybean plants were grown under high P or P-deficient conditions.
• Plants were subjected to well-watered, severe water deficit at R5, or moderate followed by severe water deficit (V5 + R5) regimes.
• Physiological parameters including photosynthetic rate, stomatal conductance, and mesophyll conductance were measured.

Main Results:

• P deficiency delayed photosynthetic decline under water stress but accelerated recovery of photosynthetic rate and stomatal conductance.
• In drought-sensitive cultivars, P deficiency enhanced recovery after multiple stress cycles via increased mesophyll conductance.
• Grain protein concentration decreased, while oil content, particularly unsaturated fatty acids, increased under P deficiency.

Conclusions:

• P deficiency modifies physiological responses in water-sensitive soybean genotypes, influencing their drought recovery capacity.
• The findings highlight a complex interaction between nutrient status and water stress resilience in soybean.
• Altered grain composition under P deficiency has implications for crop quality and end-use characteristics.