Elevated phosphorus impedes manganese acquisition by barley plants

Area of Science:

• Plant Nutrition
• Soil Science
• Agricultural Chemistry

Background:

• Manganese (Mn) deficiency in cereal crops is rising, potentially linked to increased soil phosphorus (P) from manure and fertilizers.
• High soil P may negatively impact Mn availability and uptake in plants.

Purpose of the Study:

• To investigate the hypothesis that elevated phosphorus supply induces manganese deficiency in barley.
• To examine the direct interaction between phosphorus and manganese during root uptake and translocation.

Main Methods:

• Conducted hydroponics and soil experiments with varying phosphorus levels.
• Utilized on-line inductively coupled plasma mass spectrometry (ICP-MS) to monitor Mn uptake in real-time.
• Assessed Mn concentration in barley leaves and chlorophyll fluorescence to identify deficiency symptoms.

Main Results:

• Elevated phosphorus supply significantly reduced manganese uptake by barley roots.
• Plants with high P had up to 50% lower Mn concentration in young leaves compared to P-limited plants.
• Increased leaf concentrations of Iron (Fe), Copper (Cu), and Nitrogen (N) with higher P supply indicated a specific effect on Mn, not a general dilution.

Conclusions:

• Elevated phosphorus supply directly interferes with manganese uptake in barley roots.
• This interaction can induce manganese deficiency in barley shoots, impacting crop production.
• Findings are critical for commercial agriculture on soils with high phosphorus levels.