Understanding the AM fungal association in flooded rice under elevated CO2 condition

Abstract

Arbuscular Mycorrhizal fungi (AMF) exhibit multifunctional mutualistic symbiosis with plants. The beneficial effect of AMF has been exploited for most of the crop plants but its role in flooded rice cultivation particularly under elevated CO2 is not much dissected. Most of the research findings revealed that, the higher dose of phosphorous fertilizer application limits the AMF colonization in crop plants. In view of above, the present study was conducted to understand whether recommended dose of phosphorous fertilizers have any negative effects on AMF association in flooded rice under elevated CO 2 condition. This experiment comprised of four treatments, which include three methods of AMF inoculation and an uninoculated control. The entire experiment was maintained at ambient and elevated CO2 (550 ± 20 and 700 ± 20 ppm) in open top chamber. In general, the mycorrhizal root colonization and sporulation was 1.2–2.5 times higher in AMF inoculated treatments than uninoculated control. Among different methods of mycorrhizal application, transplanting of mycorrhized seedlings or mycorrhized seedlings along with basal application of AMF increased sporulation and AMF colonization by 32–69% and 14–56%, respectively compared to uninoculated control after 60 days of planting. The grain phosphorous content was increased by 14.0 - 21.4% in AMF inoculated treatments as compared to uninoculated control in both ambient and eCO2 conditions. The present study revealed that, application of AMF along with recommended dose of fertilizers (80:40:40 NPK kg ha −1) significantly improves mycorrhizal root colonization, sporulation and plant P uptake in anaerobic rice under ambient and elevated CO 2 condition.