Biological nitrogen fixation and biomass accumulation within poplar clones as a result of inoculations with diazotrophic endophyte consortia



  • Sustainable production of biomass for bioenergy relies on low-input crop production. Inoculation of bioenergy crops with plant growth-promoting endophytes has the potential to reduce fertilizer inputs through the enhancement of biological nitrogen fixation (BNF).
  • Endophytes isolated from native poplar growing in nutrient-poor conditions were selected for a series of glasshouse and field trials designed to test the overall hypothesis that naturally occurring diazotrophic endophytes impart growth promotion of the host plants.
  • Endophyte inoculations contributed to increased biomass over uninoculated control plants. This growth promotion was more pronounced with multi-strain consortia than with single-strain inocula. Biological nitrogen fixation was estimated through 15N isotope dilution to be 65% nitrogen derived from air (Ndfa).
  • Phenotypic plasticity in biomass allocation and branch production observed as a result of endophyte inoculations may be useful in bioenergy crop breeding and engineering programs.