Phosphorus mobilization and uptake in mycorrhizal rice (Oryza sativa L.) plants under flooded and non-flooded conditions

Abstract

Phosphorus (P) deficiency severely limits rice production in the world. Colonization of plant root with arbuscular mycorrhizal fungi (AMF) may have a considerable consequence for P uptake and plant growth. In contrast to other crop species, there is little experimental evidence about the role of mycorrhizal colonization in lowland rice plants. This study was undertaken to examine whether inoculation of rice plants can contribute in the mobilization and uptake of insoluble P form. In addition, an attempt was made to compare flooded plants with non-flooded ones in their mycorrhizal responsiveness. In one experiment, insoluble P was supplied for plants inoculated either with Glomus mosseae or Glomus intraradices, then growth and P uptake was determined. Results showed that colonization with AMF significantly improved uptake of P derived from insoluble P source. In other experiment, rice plants were inoculated with Glomus mosseae or Glomus intraradices in non-flooded nurseries and then transplanted either to flooded or non-flooded conditions. Root colonization by AMF was decreased due to flooding conditions from 43% to 27%. Nevertheless, the plant growth responded positively (117% increase) to inoculation when grown at flooded conditions, while dry matter of non-flooded plants was diminished up to 64% by inoculation. Mycorrhizal colonization had also a significant contribution in the uptake of P and K in flooded but not in non-flooded plants.