A meta-analysis of arbuscular mycorrhizal effects on plants grown under salt stress

Abstract

Salt stress limits crop yield and sustainable agriculture in most arid and semiarid regions of the world. Arbuscular mycorrhizal fungi (AMF) are considered bio-ameliorators of soil salinity tolerance in plants. In evaluating AMF as significant predictors of mycorrhizal ecology, precise quantifiable changes in plant biomass and nutrient uptake under salt stress are crucial factors. Therefore, the objective of the present study was to analyze the magnitude of the effects of AMF inoculation on growth and nutrient uptake of plants under salt stress through meta-analyses. For this, data were compared in the context of mycorrhizal host plant species, plant family and functional group, herbaceous vs. woody plants, annual vs. perennial plants, and the level of salinity across 43 studies. Results indicate that, under saline conditions, AMF inoculation significantly increased total, shoot, and root biomass as well as phosphorous (P), nitrogen (N), and potassium (K) uptake. Activities of the antioxidant enzymes superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase also increased significantly in mycorrhizal compared to nonmycorrhizal plants growing under salt stress. In addition, sodium (Na) uptake decreased significantly in mycorrhizal plants, while changes in proline accumulation were not significant. Across most subsets of the data analysis, identities of AMF (Glomus fasciculatum) and host plants (Acacia nilotica, herbs, woody and perennial) were found to be essential in understanding plant responses to salinity stress. For the analyzed dataset, it is concluded that under salt stress, mycorrhizal plants have extensive root traits and mycorrhizal morphological traits which help the uptake of more P and K, together with the enhanced production of antioxidant enzymes resulting in salt stress alleviation and increased plant biomass.

A Meta-Analysis of the Impact of Anaerobic Soil Disinfestation on Pest Suppression and Yield of Horticultural Crops

“…Although designating multiple studies from one publication has the disadvantage of increasing the dependence among studies that for the purposes of meta-analysis are assumed to be independent (Gurevitch and Hedges, 1999), the greater number of studies increases statistical power (Lajeunesse and Forbes, 2003). This approach has been used commonly in plant biology meta-analyses (e.g., Holmgren et al, 2012; Veresoglou et al, 2012; Mayerhofer et al, 2013; Chandrasekaran et al, 2014). The entire data set included 900 studies from eight countries ( Table 1 ).…”

Influence of Arbuscular Mycorrhizal Fungi on Rooting Ability of Auxin Treated Stem Cuttings of Dalbergia melanoxylon (Guill and Perr.)

“…The beneficial effect of inoculation at initial stage of plant development is that it can promote AMF symbiosis resulting to increase plant growth in the nursery and improving performance after planting in the field (Kung'u et al, 2008;Wang et al, 2008). Furthermore through the formation of symbiotic associations with plant roots, AMF provide a variety of ecological functions affecting plant flowering, with subsequent changes to the pollinator community and can be more productive under growing conditions where nutrients and water may be limiting productivity (Cahill et al, 2008;Chandrasekaran et al, 2014). Also AMF facilitates higher water absorption and nutrient uptake in plants, which in turn and helps to combat various diseases, increase torelance to abiotic stresses and enhances plant growth (Querejeta et al, 2003;Bisht et al, 2009;Bati et al, 2015).…”

Use of mycorrhizal fungi as a strategy for improving the drought tolerance in date palm (Phoenix dactylifera)

“…They can act as phytoalexins (induced phenols), phytoanticipins (constitutive phenols), structural barriers (synthetic precursors of the line or as activators of genes defense (Nicholson and Hammerschmidt, 1992;Hammerschmidt, 1999). The endomycorhization can affect secondary metabolism by stimulating the synthesis pathway of phenolic compounds (Krishna and Bagyaraj, 1984), phytoalexins (Morandi and Gianinazzi-Pearson, 1986) and peroxidases (Spanu and Bonafante-Fasolo, 1988;Chandrasekaran et al, 2014). The activities of peroxidase can be detected throughout the life cycle of the plant, and they are involved in several processes including auxin catabolism (Gaspar et al, 1982), the linkage of cell wall compounds (Grabber et al, 2002;Price et al, 2003), cell elongation (Cosgrove, 2001), the formation of suberin (Keren-Keiserman et al, 2004) and defense against pathogens (Passardi et al, 2005).…”