Could the interaction between arbuscular mycorrhizal fungi and biostimulants improve the plant physiological status of Prosopis alba seedlings?

Mycorrhizae and biostimulants are among the most innovative biological techniques used in large-scale food production. Positive effect son plant growth have been reported. However, the use of these "biofertilizers" in afforestation is limited. This study aimed to evaluate the synergy between arbuscular mycorrhizal fungi (AMF) and foliar biostimulant applications (phytoextracts) on an important Chaco native species (Prosopis alba) during the nursery stage. We tested biochemical parameters (MDA, malondialdehyde, an oxidative stress biomarker, and photosynthetic pigments) on P. alba seedlings sprayed with three different phytoextracts and inoculated with mycorrhizal strains of different local origins. Even though the statistical model was not significant at the preliminary level, our results showed that inoculated plants with one of the mycorrhizal strains (M2) could exhibit better results than other plants. For example, plants inoculated with M2 in combination with foliar applications of Larrea divaricata at 3% w/v showed a lower accumulation of the oxidative stress biomarker, MDA (p>0.5). Besides, M2 treated plants in combination with a phytoextract mixture (L. divaricata 1% w/v and Ilex paraguariensis 1% w/v) exhibited a higher biosynthesis of photosynthetic pigments (p>0.5). However, apparently, M2 showed better results in interaction with a biostimulant (M2 without a biostimulant is the treatment with the highest accumulation of MDA, p>0.5). Although there were no significant differences, trends indicate positive relationships between neck diameter and mycorrhizal response in plants treated with M1 with foliar applications of Larrea divaricata at 3% w/v. However, height does not consistently respond to mycorrhizae interacting with biostimulants. Consequently, deeper analysis is needed to understand the effect of the interaction between AMF with biostimulants for improving the plant's physiological status. Deepening research in this regard will result in significant benefits for restoration activities.