Application of Exogenous Protectants Mitigates Salt-Induced Na+ Toxicity and Sustains Cotton (Gossypium hirsutum L.) Seedling Growth: Comparison of Glycine Betaine and Salicylic Acid

Abstract

Soil salinization adversely affects agricultural productivity. Mitigating the adverse effects of salinity represents a current major challenge for agricultural researchers worldwide. The effects of exogenously applied glycine betaine (GB) and salicylic acid (SA) on mitigating sodium toxicity and improving the growth of cotton seedlings subjected to salt stress remain unclear. The treatments in a phytotron included a control (CK, exogenously untreated, non-saline), two NaCl conditions (0 and 150 mM), four exogenous GB concentrations (0, 2.5, 5.0, and 7.5 mM), and four exogenous SA concentrations (0, 1.0, 1.5, and 2.0 mM). The shoot and roots exposed to 150 mM NaCl without supplementation had significantly higher Na+ and reduced K+, Ca2+, and Mg2+ contents, along with lowered biomass, compared with those of CK. Under NaCl stress, exogenous GB and SA at all concentrations substantially inversed these trends by improving ion uptake regulation and biomass accumulation compared with NaCl stress alone. Supplementation with 5.0 mM GB and with 1.0 mM SA under NaCl stress were the most effective conditions for mitigating Na+ toxicity and enhancing biomass accumulation. NaCl stress had a negative effect on plant growth parameters, including plant height, leaf area, leaf water potential, and total nitrogen (N) in the shoot and roots, which were improved by supplementation with 5.0 mM GB or 1.0 mM SA. Supplementation with 5.0 mM exogenous GB was more effective in controlling the percentage loss of conductivity (PLC) under NaCl stress.

Protoplast Dissociation and Transcriptome Analysis Provides Insights to Salt Stress Response in Cotton

“…Based on the previous studies [ 28 , 29 ], 150 mM NaCl was regarded as a better concentration to study cotton plant response to salinity stress ( Figure 2 A). Here, we detected the effect of 150 mM NaCl on protoplast isolation from cotton root tips at different time intervals (0.5 h, 1 h and 2 h of treatments).…”

Resveratrol Alleviates the KCl Salinity Stress of Malus hupenensis Rhed. Seedlings by Regulating K+/Na+ Homeostasis, Osmotic Adjustment, and Reactive Oxygen Species Scavenging

“…M. hupehensis is one of the most popular rootstocks for apple production and cultivation [51], but unfortunately suffers from serious KCl stress due to the huge amount of potassium fertilizer applied to orchards. Introducing exogenous substances such as plant growth regulator, osmotic adjustment substances, and antioxidants effectively alleviates salt stress [52,53,54]. As an antimicrobial phytoalexin, Res alleviates NaCl stress in citrus seedlings [42].…”

Sodium Toxicity: Should NaOH Be Substituted by KOH in Plant Tissue Culture?

“…Salt stress reduces water uptake, leading to cell dehydration and changes in cell turgor, inducing osmotic stress. In the long term, accumulation of Na to toxic levels induces ionic toxicity leading to Ca 2+ , Mg 2+ and K + deficiency and to other nutrient imbalances (Munns and Tester, 2008;Hamani et al, 2021). Salt stress impairs growth both at whole plant and cellular level by low osmotic potential, nutritional imbalance, specific ion effect, or a combination of these factors.…”