Sepehr, E. | Search bioRxiv

bioRxiv2023

Effects of enriched biochar treatments on CO2 release, soil nitrate and ammonium, and wheat growth parameters in saline soils

The effects of treatment with simple and enriched biochar on microbial respiration, nitrate and ammonium concentrations, and wheat growth parameters in saline soils were investigated using a completely randomized factorial experimental design with three replications, three soil salinity levels (1.5, 4.5 and 9 dS.m-1), and five biochar treatments including control, 2% simple (SB) or enriched biochar (EB) amendment, and 4% SB or EB amendment. The basal respiration rate and the concentrations of ammonium, and nitrate were measured at multiple time points. Additionally, total soil nitrogen, organic carbon, and microbial biomass carbon, microbial biomass nitrogen, and microbial biomass phosphorus were measured together with the height and fresh and dry weight of wheat after a 100-day growth period and at the end of the experiment. Salinity significantly affected basal respiration, nitrate and ammonium concentrations, plant height, and wet and dry weight. Biochar amendment significantly affected pH, basal respiration, nitrate and ammonium concentrations, total soil nitrogen, soil organic carbon, microbial biomass carbon, microbial biomass nitrogen, and microbial biomass phosphorus in both rhizosphere and non-rhizosphere soil, as well as wheat height, and wet and dry weight. The interaction between salinity and biochar significantly affected nitrate and ammonium concentrations and also plant height and fresh and dry weight. Finally, the effects of different biochar amendments and salinity levels on the basal respiration rate and the concentrations of nitrate and ammonium varied significantly over time. Overall, the results obtained show that biochar amendment can significantly moderate the adverse effects of soil salinity, especially if enriched biochar is used.

plant biology↗

bioRxiv2022

Potassium homeostasis and signaling as a determinant of Echinacea species tolerance to salinity stress

Salt tolerant is strongly related to potassium (K+) retention in plant tissues under salt stress conditions. However, it is unclear for different Echinacea species. So, mechanistic basis of four Echinacea species (i.e. Echinacea purpurea, Echinacea angustifolia, Echinacea pallida, and Echinacea sanguinea) to salinity stress tolerance, and K+ retention were assessed in the present study. Non-invasive microelectrode ion flux measuring, DHAR and MDHAR activities, and pharmacological measurements were performed based on the standard methods. Ion flux measurements revealed higher K+ efflux in E. pallida and E. sanguinea species compared to the E. purpurea and E. angustifolia species in the elongation zone. Higher salinity-induced H+ efflux was found in the elongation zone than mature zone. However, E. angustifolia and E. purpurea had more Ca2+ influx compared to E. pallida and E. sanguinea species. Net K+ efflux decreased (> 90%) in the presence of TEA and GdCl3. Increasing of Ca2+ uptake and K+ loss in four Echinacea species roots were found in the presence of 0.3 mM Cu/Ascorbate (Cu/Asc). The significant role of H+-ATPase in H+ efflux was demonstrated by Sodium orthovanadate. Ultimately, the physiological properties of Echinacea species have a critical role in salinity-resistant/sensitive differences. Future scientific understanding of Echinacea species physiognomies may be necessary for better understanding of the plant behavior to salinity stress. One-sentence summaryHigher K+ efflux in E. pallida and E. sanguinea species as a result of NaCl and ROS act as a metabolic switch to save energy for adaptations and repairs in salinity stress conditions.

plant biology↗