Amazonian Microorganism Strains Improve Physiological Performance to Oil Palm Seedlings Growth Promote

Elaeis guineensis Jacq. is an palm that has stood out in the food and biofuel industries. However, greater productivity and better oil yield in the field depend on good management from the seedling stage. In nurseries, initial growth is relatively slow and the long time taken to produce seedlings increases the water and chemical inputs use. Beneficial microorganisms have been used to promote seedling growth, but their effectiveness can be impaired in adverse soil and climate conditions. The study objective was to evaluate the Amazonian strains inoculating effectiveness of the Trichoderma Asperellum mix (UFRAT06, UFRAT09 and UFRAT52), Trichoderma Asperellum (UFRAT12) and Bacillus amyloliquefaciens (UFRAB01) in growth promotion and physiological performance of the oil palm seedlings. The experiment was conducted under nursery conditions with five treatments (strain inoculation) and one control (no inoculation). Amazonian strains inoculation increased all growth and biomass parameters compared to the control. In gas exchange, the increases were significant for net CO2 assimilation, stomatal conductance and transpiration in inoculated seedlings in relation to non-inoculated. Total soluble sugar and starch contents decreased in inoculated seedlings in relation to the control. Probably, the greater carbohydrates consumption is associated with a large demand for energy to sustain the high CO2 assimilation, which in turn may be converted into greater biomass accumulation and, consequently, greater growth. The results show that Amazonian strains inoculation is effective in activating physiological mechanisms that lead to greater growth promotion. Therefore, future studies can move forward to elucidate the molecular mechanisms that are involved in the greater efficacy of growth promotion in oil palm seedlings inoculated with Trichoderma Asperellum strains, Bacillus amyloliquefaciens and Bacillus spp. native to the Amazon. The greater inoculation effectiveness accelerates growth and reduces nursery time, in addition to reducing production costs and alleviating environmental impacts due to lower chemical fertilizers consumption.