Arbuscular Mycorrhizal Fungi and Dry Raw Garlic Stalk Amendment Alleviate Continuous Monocropping Growth and Photosynthetic Declines in Eggplant by Bolstering Its Antioxidant System and Accumulation of Osmolytes and Secondary Metabolites

Abstract

Vegetable production under plastic sheds severely threatens regional eco-sustainability via anthropogenic activities (excessive use of agrochemicals, pesticides) and problems associated with replanting. Long-term successive cropping across growing seasons induces continuous cropping stress, whose effects manifest as diminished plant growth. Therefore, it is imperative that we develop environmentally sustainable approaches, such as replacing agrochemicals with vegetable waste like dry raw garlic stalk (DRGS) or use biofertilizers like arbuscular mycorrhizal fungi (AMF) (e.g., Diversispora epigaea). In this study, the influence of AMF on the growth, biochemical attributes, antioxidant defense system, phytohormones, accumulation of osmolytes, phenols, and mineral elements in eggplant grown on DRGS-amended soils under continuous monocropping (CMC) was studied. The results showed that inoculation with AMF or the DRGS amendment could improve the pigments’ content, photosynthesis, and antioxidant defense system; augmented phytohormones synthesis (except for ABA), and increased the leaves’ mineral nutrients. These parameters were enhanced most by the combined application of AMF and DRGS, which also increased the concentration of osmolytes, including proline, sugars, and free amino acids in eggplant when compared with the control. Furthermore, either AMF and DRGS alone, or in combination, ameliorated the induced stress from continuous cropping by reducing the incidence of Fusarium wilt and production of ROS (reactive oxygen species); lipid peroxidation underwent maximal reduction in plants grown under the combined treatments. The AMF, DRGS, and AMF + DRGS exhibited a lower disease severity index (33.46, 36.42, and 43.01%), respectively, over control. Hence, inoculation with AMF coupled with DRGS amendment alters the photosynthetic attributes in eggplant through the upregulation of its antioxidant system and greater accumulation of osmolytes, which led to the improved growth and yield of eggplant.

Biomass, Essential Oil Yield, and Composition of Marjoram as Influenced by Interactions of Different Agronomic Practices under Controlled Conditions

“…The increase in the leaf area when increasing the nitrogen application rate in some cases may be attributed to the weakness of this element and its role in increasing the division of meristematic cells, which is reflected positively on the increase in the size of the vegetative system, including the height of the plant. Ghani et al [ 63 ] also observed that increasing nitrogen fertilizer increased the leaf area of Sorghum bicolor . L. In the present study, sandy loam soil enhanced the leaf area of marjoram plants.…”

Arbuscular Mycorrhizal Fungi Improve the Growth, Water Status, and Nutrient Uptake of Cinnamomum migao and the Soil Nutrient Stoichiometry under Drought Stress and Recovery

“…AMF can form extensive hyphal networks in host roots and improve the growth of host plants by promoting nutrient and water uptake [ 85 ]. Additionally, AMF can help to increase chlorophyll synthesis [ 86 ], production of ROS [ 87 ], mineral solubilization [ 88 ], and photosynthesis [ 89 , 90 ] of host plants, thereby reducing abiotic stress. Moreover, AMF can effectively increase the levels of Osmoprotectants in plant leaves and provide potential protection against abiotic stress [ 80 ] and recruit other microorganisms in the soil, thereby altering the rhizosphere microbial environment of the host plants and increasing mineralization [ 91 ].…”

Different leafy vegetable cropping systems regulate growth, photosynthesis, and PSII functioning in mono-cropped eggplant by altering chemical properties and upregulating the antioxidant system

“…APX and CAT act on the same substrate, i.e., hydrogen peroxide but at different sites, with APX eliminating excess hydrogen peroxide from chloroplast while CAT from the cytosol ( Ahmad, 2010 ). Increased APX activity due to crop rotation with leafy vegetables strengthened the key radical scavenging pathways, including ascorbate-glutathione in chloroplasts leading to increased protection of major cellular pathways, including photosynthesis ( Ahanger and Agarwal, 2017a ; Ghani et al., 2022a ). Up-regulation of the activities of APX due to crop rotation prevents the formation of toxic hydroxyl radicals by assisting in the maintenance of redox homeostasis and the electron donors, including ascorbate and glutathione ( Khan and Khan, 2014 ).…”

“…Eggplant ( Solanum melongena L.) is a valuable vegetable cash crop mostly grown under plastic shed ( Wang et al., 2015 ; Ghani et al., 2022a ). Eggplant production in plastic shed heavily relies on mono-cropping systems.…”