Physiological and Biochemical Behaviors of Date Palm Vitroplants Treated with Microbial Consortia and Compost in Response to Salt Stress

Abstract

The main challenge of the agricultural sector is to develop new ecological technologies that increase the yields and the tolerance of crops to abiotic constraints, especially in arid areas. The objective of this study was to test the potential roles of biofertilizers, namely, arbuscular mycorrhizal fungi (AMF), a native AMF consortium (AMF1) and an exotic AMF strain (AMF2); plant growth-promoting rhizobacteria (PGPR); and compost (comp), applied separately or in combination, in improving the tolerance of date palm vitroplants to salt stress. Plants were grown under non-stressed (0 mM NaCl) or stressed conditions (120 and 240 mM NaCl). Salt stress negatively affected growth and physiological parameters. However, biofertilizers used alone or in combination increased these traits in either the presence or absence of salinity. The two tripartite combinations PGPR+AMF1+Comp and PGPR+AMF2+Comp efficiently increased plant height compared to the controls, with respective enhancements of 47% and 48% under non-stressed conditions (0 mM), 44% and 43% under 120 mM NaCl and 42% and 41% under 240 mM NaCl. Moreover, under 240 mM NaCl level, the PGPR, AMF1+Comp and PGPR+AMF1+Comp treatments improved the shoot dry weight by 128%, 122% and 113% respectively compared to the stressed control plants submitted to 240 mM NaCl. The tripartite combinations PGPR+AMF1/AMF2+Comp improved salt stress tolerance of plants by increasing plant growth, accumulation of osmotic adjustment compounds and antioxidant enzyme activity compared to control plants and the other treatments.

Mitigation adverse effects of salinity stress on wheat plants by co-inoculation of plant growth promoting rhizobacteria, arbuscular mycorrhizal fungi and compost amendment

“…Various studies have reported the combined synergistic effect of compost, and PGPR in alleviate salinity and drought stress of wheat plants (Kanwal et al, 2017;Yaseen et al, 2020). Similarly, various studies have reported that the dual or triple combination of PGPR, AMF, and compost has a strong ability to mitigate the adverse effects of salinity stress on plant, by enhancing photosynthesis and water status (Bharti et al, 2016: Toubali et al, 2020. They also demonstrated that, in the interactions between plants and AMF, PGPR and compost, benefit each other from this mutualistic association.…”

Evaluation of Young Date Palm Tolerance to Salinity Stress under Arbuscular Mycorrhizal Fungi and Compost Application

“…The activity of the antioxidant enzymes mainly decreased between 10 and 14 months of cultivation, in the presence of saline stress, where the shoot SOD activity showed the greatest decline (25%) between the two harvests in compost-treated plants (Figures S2 and S3). The significant increase in antioxidant enzyme activity in treated plants in the presence of saline stress after 10 months of cultivation probably led to a significant decrease in stress markers [11,12]. This decrease was more significant after 14 months of cultivation.…”

Biostimulants as Innovative Tools to Boost Date Palm (Phoenix dactylifera L.) Performance under Drought, Salinity, and Heavy Metal(Oid)s’ Stresses: A Concise Review

“…AMF-assisted enhancement of the photosynthetic pigment content, such as chlorophyll, has been reported in date palm plants subjected to salinity [81,82]. According to these studies, AMF enhanced the uptake of minerals, especially, Mg which represents the major center of the chlorophyll molecule [65].…”

“…Salinity affects the ability of date palm to absorb water due to the osmotic impact and alteration in cell-water relations [76]. Moreover, it exerts a detrimental impact on photosynthetic pigments [80,81]. Several studies, however, found that, when salinity increased, the content of chlorophyll considerably decreased [66,76].…”

“…The important capacity of ROS scavenging can be attributed to AMF boosting the antioxidant machinery. The high activity of these enzymes in mycorrhizal date palm plants reduced the oxidative damage, with less accumulation of MDA and H 2 O 2 [81,82]. Indeed, AMF possess various oxidative stress-related genes (e.g., SOD genes).…”