Arbuscular mycorrhizae modify winter wheat root morphology and alleviate phosphorus deficit stress

Arbuscular mycorrhizal (AM) root colonization is known to have beneficial effects on plant growth especially under phosphorus (P) deficit conditions. The objectives of present study were: (i) to quantify changes in early wheat root development of AM-inoculated (AMI) and AM-free (AMF) roots under limited P availability; (ii) to assess possible mitigating effect of AM inoculation on photochemical efficiency under P deficit stress. AMI (inoculated with Rhizophagus irregularis) and AMF wheat plants were grown for 20 days in low (1 mu mol/L) and high (50 mu mol/L) P treatments. AM inoculation affected root morphology and shoot P concentration in low P treatment. AM inoculation alleviated reduction of the total root length in low P treatment, mainly due to an increase of fine roots length (< 0.5 mm). Contrastingly, shoot dry weight was reduced by AM inoculation in low P treatment. P deficiency decreased photochemical efficiency of wheat plants. However, due to increased sink capacity and facilitated nutrient concentrations AM inoculation alleviates phosphorus deficit stress and increased photochemical efficiency.