Abstract
Soil available phosphorus (P) is one of the main factors limiting plant growth and yield. This study aimed to determine the role of arbuscular mycorrhizal fungi (AMF) in P-use efficiency in two maize genotypes with contrasting root systems in response to low P stress. Maize genotypes small-rooted Shengrui 999 and large-rooted Zhongke 11 were grown in rhizoboxes that were inoculated with or without AMF (Funneliformis mosseae) under low P (no added P) or optimal P (200 mg kg(-1)) for 53 days. Low P stress significantly inhibited shoot and root growth, photosynthesis, tissue P content, and root P concentration in both genotypes. Shengrui 999 was more tolerant to P stress with less reduction of these traits compared to Zhongke 11. Shengrui 999 had a higher AMF infection rate than Zhongke 11 at both P levels. Under P deficit, inoculation with AMF significantly promoted plant growth and P uptake in both genotypes with more profound effects seen in Zhongke 11, whilst Shengrui 999 was more dependent on AMF under optimal P. Low P stress inhibited the growth and physiological attributes of both genotypes. The small-rooted Shengrui 999 was more tolerant to low P than Zhongke 11. Inoculation with AMF alleviates low P stress in both genotypes with a more profound effect on Zhongke 11 at low P and on Shengrui 999 at high P conditions.