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Mechanisms for tolerance of very high tissue phosphorus concentrations in P tilotus polystachyus
Author(s) -
AZIZ TARIQ,
LAMBERS HANS,
NICOL DION,
RYAN MEGAN H.
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12450
Subject(s) - phosphorus , chemistry , food science , organic chemistry
Abstract Study of plants with unusual phosphorus ( P ) physiology may assist development of more P ‐efficient crops. P tilotus polystachyus grows well at high P supply, when shoot P concentrations ( [ P ] ) may exceed 40 mg P g −1 dry matter ( DM ). We explored the P physiology of P . polystachyus seedlings grown in nutrient solution with 0–5 mM P . In addition, young leaves and roots of soil‐grown plants were used for cryo‐scanning electron microscopy and X ‐ray microanalysis. No P ‐toxicity symptoms were observed, even at 5 mM P in solution. Shoot DM was similar at 0.1 and 1.0 mM P in solution, but was ∼14% lower at 2 and 5 mM P . At 1 mM P , [ P ] was 36, 18, 14 and 11 mg P g −1 DM in mature leaves, young leaves, stems and roots, respectively. Leaf potassium, calcium and magnesium concentrations increased with increasing P supply. Leaf epidermal and palisade mesophyll cells had similar [ P ]. The root epidermis and most cortical cells had senesced, even in young roots. We conclude that preferential accumulation of P in mature leaves, accumulation of balancing cations and uniform distribution of P across leaf cell types allow P . polystachyus to tolerate very high leaf [ P ].