Release of tartrate as a major carboxylate by alfalfa (Medicago sativa L.) under phosphorus deficiency and the effect of soil nitrogen supply

• Published in: Plant and soil 2020-04, Vol.449 (1-2), p.169-178
• Main Authors: He, Honghua, Wu, Miaomiao, Guo, Lei, Fan, Chenbin, Zhang, Zekun, Su, Rui, Peng, Qi, Pang, Jiayin, Lambers, Hans
• Format: Article
• Language: English
• Subjects: Acidification; Alfalfa; Alkaline soils; Ammonium; Ammonium compounds; Ammonium nitrate; Ammonium paratungstate; Availability; Biomedical and Life Sciences; Carboxylates; Ecology; Fertilizers; KDP crystals; Life Sciences; Medicago sativa; Nitrogen; Nodulation; Phosphatases; Phosphates; Phosphorus; Phosphorus content; Physiological aspects; Physiological responses; Plant biomass; Plant growth; Plant Physiology; Plant Sciences; Potassium phosphate; Potassium phosphates; Regular Article; Roots; Soil investigations; Soil Science & Conservation; Soils
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-020-04481-9

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.