White lupin (Lupinus albus L.) exposed to elevated atmospheric CO2 requires additional phosphorus for N2 fixation

Abstract Purpose The steady rise of atmospheric CO 2 concentrations enhances symbiotic N fixation and plant growth. However, it is largely unknown whether more P required to enhance under elevated . We examined if plants require support enhanced fixation. Methods White lupin ( Lupinus albus L. cv. Kiev) was grown in nutrient solution ambient (380 ppm) (700 levels at 0, 2, 5, 12, 25 50 µM P. Nodulation, nodule function, growth were assessed 4 6 weeks post inoculation. Excess cation uptake proton release also analysed due its importance acquisition. Results Elevated increased the critical concentration for fixation, indicating need acquire additional greater improved P-deficient by increasing specific nitrogenase activity. excess which roots. Conclusions As demand P, thereby mitigate effect deficiency on Despite this, could P-limiting environments.