Boosting Date Palm (Phoenix dactylifera L.) Growth under Drought Stress: Effects of Innovative Biostimulants

Drought circumstances, characterized by limited water, severely impede plants growth performance, resulting in a cyclical drop in agricultural productivity. Soil microorganisms, such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR), in addition to compost, can help plants' productivity, amongst extreme weather events. Therefore, the present study intended to assess the effects of biostimulants application on date palm vitroplants, subjected to drought stress and under field conditions. The tested biostimulants were AMF consortium (AMF), indigenous PGPR (B), and local green compost (C). Growth, physiological, and biochemical traits were the evaluated parameters. Soil characteristics were investigated as well. The performance of date palm vitroplants and evolution of soil were observed under well-watered (WW) and drought stress (DS) conditions. Date palm vitroplants were treated with either AMF, C, or B, separately or in combination. The obtained results showed that the inoculation of date palm vitroplants with AMF+C+B treatment credibly mitigated DS as reflected by the improvement of plant biomass (76%), rise of phosphorus uptake (293%), and boosted plant-water relationship under such conditions. Low levels of hydrogen peroxide and malondialdehyde accumulation, observed in AMF+C+B treatment, were linked with improved total soluble sugar (208%) and protein (84%) content under DS conditions. In addition, the applied native biostimulants showed a notable and positive impact on soil characteristics, which were improved especially in terms of organic matter, phosphorus, and glomalin content under DS conditions. These findings highlight the importance of associating AMF, PGPR, and compost, in order to improve date palm's resilience to drought conditions, under (semi-)arid climate variations.