Effects of Suillus luteus and S. bovinus on the physiological response and nutrient absorption of Pinus massoniana seedlings under phosphorus deficiency

Aims Pinus massoniana Lamb. is a widely distributed native species and afforestation pioneer tree in the subtropical forests of China; however, the species’ quality and productivity are significantly affected by phosphorus (P) deficiency. Although ectomycorrhizal (ECM) fungi can enhance plant adaptation to nutrient deficiency, the interactive effects of ECM fungi colonization and P availability on physiological responses and nutrient uptake in P. massoniana seedlings remain unknown. Method We compared the physiological response and nutrient absorption of uninoculated P. massoniana seedlings and seedlings inoculated with Suillus luteus or S. bovinus under three P supplies (P deficiency, 0.01 mM/L; medium P, 0.1 mM/L; and P sufficiency, 1 mM/L) in sand culture. Results P deficiency limited the seedlings growth and nutrient content but increased the antioxidant enzyme activity. S. luteus and S. bovinus significantly increased the seedlings growth under P deficiency. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) as well as the contents of malondialdehyde (MDA) and proline of inoculated and uninoculated seedlings were significantly higher under P deficiency than P sufficiency. Under P deficiency, POD and SOD activities increased with time and were higher in inoculated seedlings; however, proline contents were lower in inoculated seedlings. P deficiency decreased the P and potassium (K) contents in the roots, stems, and leaves of seedlings. Moreover, under P deficiency, S. luteus significantly improved P content in stems and leaves, whereas S. bovinus significantly improved K content in leaves. Conclusion ECM fungi increased SOD and POD activities and improved P and K absorption in P. massoniana seedlings in response to P deficiency.