Abstract
Aims: Plant growth is often limited by low soil phosphorus (P) availability, soil nitrogen (N) availability may affect plants’ responses to P supply. We studied the growth and physiological responses of alfalfa to soil P supply at different N levels. Methods: Alfalfa (Medicago sativa L.) plants were grown in an alkaline soil supplied with different levels of P (0, 5, and 20 mg kg−1) as monopotassium phosphate, and N (50 and 100 mg kg−1) as ammonium nitrate. Results: Plant biomass and P concentrations always showed positive responses to P addition but not to N addition, nodulation was inhibited by lower P supply and higher N supply. Roots released more phosphatase and carboxylates, mainly tartrate, into the rhizosheath at lower soil P supply and higher N supply. Roots always acidified the rhizosheath, but rhizosheath pH did not vary considerably among treatments. Conclusions: This study demonstrates the release of tartrate as a major carboxylate as affected by soil P supply and N supply, and highlights the importance of investigating plant adaptive strategies for P acquisition from soil with different N availability for proper application of P and N fertilizers.
Original language | English |
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Pages (from-to) | 169-178 |
Number of pages | 10 |
Journal | Plant and Soil |
Volume | 449 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 1 Apr 2020 |