Cyanobacteria and Glutathione Applications Improve Productivity, Nutrient Contents, and Antioxidant Systems of Salt-Stressed Soybean Plant

Abstract

Salt stress restricts plant performance by disrupting various physio-biochemical processes like photosynthesis. Plants growing in saline substrates show deficiencies in absorption of some essential elements due to the presence of excessive sodium (Na+) in the rhizosphere, which antagonizes beneficial cations and causing toxicity in metabolism. Cyanobacteria (CB; a natural biofertilizer) play a fundamental role in building-up soil fertility, thus increasing plant performance. Glutathione (GSH) is a well-known antioxidant, which contributes to increase salt tolerance in the plant. This work was conducted as a pot experiment (sand culture) in 2017 to study the combined effect of CB, applied as seed inoculation, and GSH, applied as foliar spray, on growth, pods and seed yields, the contents of antioxidants, osmoprotectants, and nutrients, and the antioxidative enzymes activities of soybean (Glycine max L., cv. Giza 111) plants grown under saline conditions. At fourth leaf stage (21 days after sowing; DAS), CB-pretreated seedlings were supplemented with NaCl (150 mM) along with Hoagland′s nutrient solution, and at the same time seedlings were sprayed with 1 mM GSH. Samples were taken at 60 DAS to assess morphological, physio-biochemical and antioxidant defense systems attributes. Results showed that the integrative application of CB and GSH under saline conditions was effective in improving significantly the growth characteristics, yield components, photosynthetic efficiency (pigments contents and chlorophyll fluorescence), membrane stability index, relative water content, contents of soluble sugars, free proline, ascorbic acid, glutathione, α-tocopherol, and protein, and activities of superoxide dismutase, catalase, and guaiacol peroxidase. The contents of macronutrients (N, P, K+, and Ca2+) were also increased significantly in Glycine max plants compared to the stressed control. In contrast, Na+ content and electrolyte leakage were significantly reduced. Our results recommend using the combined CB (as seed inoculation) and GSH (as foliar spray) application for soybean plantss to grow well under saline conditions.

Silymarin-Enriched Biostimulant Foliar Application Minimizes the Toxicity of Cadmium in Maize by Suppressing Oxidative Stress and Elevating Antioxidant Gene Expression

“…These positive results examined in this study were positively reflected in maize plant growth and dry matter accumulation ( Figure 1 , Table 6 ). Our findings are consistent with those in [ 2 , 5 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. Restoration of growth and dry matter accumulation of Cd-stressed maize plants are also due to the positive impacts of proline, AsA, and GSH present in MEg-Sm on increasing hormones (e.g., IAA, GA 1 , GA 3 , cytokinins including trans-zeatin, SA) content and homeostasis, which are necessary to restore the developmental growth of stressed plants [ 20 , 23 , 60 , 61 , 62 ].…”

“…Among the major growth stimulators present in MEg-Sm, proline, AsA, and GSH contents were greatly increased in Cd-stressed plants and contributed to stabilizing and maintaining cell membranes against stress damage [ 2 , 5 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. These positive effects of these antioxidants might be attributed to their roles in minimizing the Cd content or other toxic elements and the levels of oxidative stress markers (O 2 • − and H 2 O 2 ; Figure 2 , Table 6 ), thus minimizing lipid peroxidation in cell membranes.…”

Influence of Cyanobacterial Biofertilizer on the Response of Zea mays Plant to Cadmium-stress

“…These findings were in accordance with numerous other reports for different plant species such as maize (Thajuddin & Subramanian, 2005) and rice (Prasanna et al, 2012). The enhancement of maize growth may be related to the ability of CB to supply the plants by several nutrients, in addition to lowering soil pH that may promote soil nutrient availability (Zaki et al, 2019). Khalil & El-Noemani (2015) suggested that CB improves soil chemical properties and strengthen biological and physical characters which represent supportive factors for root development.…”

Exogenous glutathione-mediated tolerance to deficit irrigation in salt-affected Capsicum frutescence (L.) plants is connected with higher antioxidant content and ionic homeostasis

“…It can prevent water loss or preserve leaf RWC (Abd El-Mageed et al, 2018). Respectively, Merwad et al (2018) and Zaki et al (2019), using the soybean and cowpea plants, reported the highest levels of proline and soluble sugars by exogenous GSH under drought and saline treatments.…”