Effects of Glomus intraradices on the growth and reactive oxygen metabolism of foxtail millet under drought

Abstract

Foxtail millet (Setaria italica L.) is an ancient domesticated crop grown in arid and semi-arid Africa and Eurasian continent. This study investigated the effects of arbuscular mycorrhizal (AM) fungi (Glomus intraradices) and water stress on the growth and reactive oxygen metabolism of foxtail millet under greenhouse pot conditions. After two soil water availability treatments [well-watered (WW) −0.11 MPa; water-stressed (WS) −0.68 MPa] for 31 days, G. intraradices could colonize well in the roots of foxtail millet. Water stress inhibited AM colonization, plant growth and crop yield, and also increased reactive oxygen metabolism and antioxidant enzyme activities of foxtail millet. G. intraradices-inoculated foxtail millet had greater plant height, collar diameter, panicle heigh, panicle weight and grain weight, higher enzyme activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione reductase (GR), and lower concentration of malondialdehyde (MDA) , H2O2, and O2 ·-, when compared with non-inoculated foxtail millet under both WW and WS conditions. Our results demonstrated that G. intraradices-inoculated foxtail millet showed higher drought-tolerance by improving their growth and productivity, reactive oxygen species (ROS) and antioxidant enzyme activities, compared with non-inoculated foxtail millet. This indicates that G. intraradices inoculation is a potential method for enhancing the performance of foxtail millet under drought conditions.