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Key messagePiriformospora indica confers salt tolerance in tomato seedlings by increasing the uptake of nutrients such as N, P and Ca, improving K+/Na+ homoeostasis by regulating the expression of NHXs, SOS1 and CNGC15 genes, maintaining water status by regulating the expression of aquaporins.Piriformospora indica, an endophytic basidiomycete, has been shown to increase the growth and improve the plants tolerance to stressful conditions, especially salinity, by establishing the arbuscular mycorrhiza-like symbiotic relationship in various plant hosts. In the present research, the effect of NaCl treatment (150 mM) and P. indica inoculation on growth, accumulation of nutrients, the transcription level of genes involved in ionic homeostasis (NHXs, SOS1 and CNGC15) and regulating water status (PIP1;2, PIP2;4, TIP1;1 and TIP2;2) in roots and leaves of tomato seedlings were investigated. The P. indica improved the uptake of N, P, Ca and K, and reduced Na accumulation, and had no significant effect on Cl accumulation in roots and leaves. The endophytic fungus also increased in K+/Na+ ratio in roots and leaves of tomato by regulating the expression of NHX isoforms and upregulating SOS1 and CNGC15 expression. Salinity stress increased the transcription of PIP2;4 gene and reduced the transcription of PIP1;2, TIP1;1 and TIP2;2 genes compared to the control treatment. However, P. indica inoculation upregulated the expression of PIP1;2 and PIP2;4 genes versus non-inoculated plants but did not have a significant effect on TIP1;1 and TIP2;2 expression. These results conclude that the positive effects of P. indica on nutrients accumulation, ionic homeostasis and water status lead to the increased salinity tolerance and the improved plant growth under NaCl treatment.

Eruca (Eruca sativa; Brassicaceae) is an important industrial crop due to its ability to grow under a wide range of climatic conditions and in poor fertility lands and also for the quality of seed oil and protein. Seed germination (SG) is an important event in plant’s life history which can significantly be influenced by several environmental factors such as temperature (T), water potential (ψ), salinity, pH, and burial depth. Therefore, this study aimed (i) to investigate the effects of these environmental factors on SG behavior of Eruca using several mathematical models, (ii) to determine the cardinal Ts and tolerance threshold value for each trait (i.e., 50% reduction than its maximum value) affected by the environmental factor, and (iii) to quantify the response of Eruca seedling growth to each environmental factor. The results indicated that Eruca SG and seedling growth were significantly influenced by these factors (P < 0.05). The estimated cardinal Ts were 1 °C for the base T, 30 °C for the optimum T, and 40.8 °C for the ceiling T. The salt and drought tolerance threshold values were 257 mM NaCl and − 1.2 MPa for SG and 247 mM NaCl and − 1 MPa for the seedling growth, respectively, suggesting that the seedling growth was more sensitive than SG under both salt and drought stresses in Eruca. In addition, the maximum SG and seedling growth were observed at pH 7 and burial depth 1.9 cm. In general, the models used in this study could describe well the response of Eruca SG under different levels of environmental factors and also their parameters could easily be used in Eruca SG simulation models. This information also could help us to better manage the production of this plant under stressful conditions and/or to determine its geographic range expansion in the world.

We quantified the seed germination responses of chicory ( Cichorium intybus L.; Asteraceae) to heat, water and salt stresses using hydrothermal time (HTT) and halothermal time (HaloTT) models. We extended the HaloTT model based on NaCl concentration to include supra-optimal temperatures. The HTT and HaloTT models enabled quantitative comparison of the effects of reduced water potentials and increased salinity on germination. Below 30 °C, the median threshold water potential permitting germination estimated by the HTT model (− 0.83 MPa) was higher than that estimated by the HaloTT model (− 1.30 MPa, after converting the median threshold NaCl concentration to osmotic potential). Ion uptake into seeds imbibed in salt solutions accounted for an average osmotic adjustment of 36% in the presence of salt stress compared to seeds imbibed in polyethylene glycol solutions. These thresholds became more positive above 30 °C with a common median ceiling temperature of 43 °C. The HaloTT models developed here accurately described germination responses to NaCl concentrations across all temperatures and incorporated both water potential and osmotic adjustment effects. With respect to seed germination, chicory could be considered as a moderately water stress tolerant species and highly tolerant to salt stress.

Medicinal plants are one of the main natural resources of Iran from ancient times. Perilla is one of the most important medicinal plants of the mint family Lamiaceae, since there is no study about adaptability of Perilla in Iran climate conditions and different fertilizer systems, this experiment was conducted in two experimental sites. The experiment was conducted as split-plot factorial based on a randomized complete block design with three replications at two experimental regions. The main factor was three chemical fertilizer levels (control, 50, 100, 200 kg/ha) and subplots were different kinds of organic fertilizer (control, humic acid, and compost application) and inoculation with Piriform osporaindica (inoculation and without). Among levels of chemical treatments, 50 and 100 kg/ha lead to a better result. Also, humic acid allows to achieve the highest amount of measured traits between different treatments of organic fertilizer. The highest plant yield (147.2 g/m²) and rosmarinic acid yield per area (3.432 g/m²) was achieved in 100 kg/ha at chemical fertilizer with humic acid and biological fertilizer application and the lowest plant yield (89.86 g/m²) and rosmarinic acid yield per area (1.253 g/m²) was observed in control. Also, the highest stomatal conductance was obtained with application of compost fertilizer (67.67 mmol H₂O m-2s-1). Integrated application of the studied fertilizers showed the more positive effect on yield and quality of Perilla than individual application of those fertilizers.

Soybean (Glycine max (L.) Merr; Leguminosae) is an important source of protein and oil for human and animal consumption. Understanding the interactions between plant growth promoting microorganisms (PGPM) and their host plants is necessary especially under stressful conditions. In this study, therefore, a set of twenty-one PGPM as well as a control (non-inoculation) treatment, were evaluated on seed germination, seedling growth and potassium uptake of soybean. Seed germination and soybean growth significantly enhanced when PGPM were applied. However, eight PGPM were selected in experiment I (optimum condition) based on the results of cluster analysis. These PGPM were then tested at three conditions including optimum (non-stress), drought (− 0.17 MPa, prepared using PEG8000) and salt (100 mM, prepared using NaCl) stress. Our findings indicated that four PGPM [Bacillus cereus (B1), Bacillus megaterium (B2), Trichoderma longibrachiatum (F1) and Trichoderma simmonsii (F2)] out of eight PGPM were better than the others in terms of promoting soybean seed germination and seedling growth at all conditions. Furthermore, the laboratory and pot experiments were carried out under the mentioned conditions to find the best combination of these PGPM (e.g., single, double, triple and quadruple forms). Therefore, single inoculation of B2, F1, F2 and triple inoculation of B1B2F2 were considered to be the best treatments due to improving seed germination, seedling growth and potassium uptake of soybean plants in both experiments. Consequently, in order to achieve the sustainable agriculture, application of these PGPM can be recommended due to either their positive effects on germination characteristics and/or improvement of soybean seedling growth under optimum and stressful conditions.

Castor bean ( Ricinus communis L.) is an important oilseed crop which can be applied for medicinal and industrial uses. Since there is no study concerning the aged castor bean seed germination response induced by ultrasound treatment under water and salt stresses. This study aimed to model the germination response of this plant under all applied treatments (i.e., aging, water deficit, salt stress, and ultrasound treatments) using mathematical models. Castor bean seeds were initially aged at 41 °C at different periods (0, 2, 4, 6, 8, and 10 days) to provide a range of sub-lots with various seed vigor. At each sub-lot, the seeds were randomly divided into two subsamples, one for ultrasound and the other for non-ultrasound treatment at each of the following water potentials ( ψ ; 0, − 0.4, − 0.8 and − 1.2 MPa; made by both polyethylene glycol 8000 and sodium chloride). At all treatments, the germination parameters were recorded. Electrolyte leakage of the seeds was measured and osmotic adjustment into the castor bean seeds was also estimated. The germination percentage and germination rate of castor bean seeds were significantly influenced by all the above-mentioned treatments ( P  < 0.01). At each aging period, the hydrotime model could accurately quantify the castor bean germination response under various ψ s (made by PEG and NaCl) with R 2 value of > 0.80. The aged and non-aged castor bean seeds could uptake the salt ions, adjust their potential and then improve their germination under saline conditions. Under non-ultrasound treatment, the osmotic adjustment was higher compared to ultrasound treatment because ultrasound can cause cell membrane damage, increase permeability by fissures on the pericarp and so reduce the ability of cells for adjusting turgor pressure into seeds. The conductivity significantly increased with aging, reflecting seed vigor loss. Ultrasound treatment increased germination parameters in both aged and non-aged seeds across all ψ s, suggesting this treatment could be used as pretreatment in castor bean seeds for improving germination characteristics, particularly under stressful conditions. Consequently, the parameters reported in the present work can be successfully used in castor bean germination simulation models. However, some field experiments will be required to examine the ability of this technique in natural conditions, which can be a suitable avenue for further research.

Global wheat production has faced, and will persist in encountering many challenges. Therefore, developing a dynamic cultivation approach generated through modeling is crucial to coping with the challenges in specific districts. The modeling can contribute to achieving global objectives of farmers’ financial independence and food security by enhancing the cropping systems. The current study aims to assess the effects of cultivars and sowing windows intricately on irrigated wheat production using the two models from Coupled Model Intercomparison Project Phase 6 (CMIP6), including ACCES-CM2 and HadGEM31-LL under two shared socioeconomic pathways (SSP245, and SSP585). A two-year on-farm experiment was conducted for parametrization and validation of the APSIM-Wheat model at two locations. The model reasonably simulated the days to anthesis, maturity, biomass production, and yield within all cultivars. The normalized root-mean-square error (RMSE) of the phenological stages was simulated and measured values were 5% and 2–4%, while the index of agreement (IOA) was in the range of 0.84–0.88 and 0.95–0.97. An acceptable agreement of the simulated biomass (RMSE = 5–7% and 0.91–0.78) and yield (RMSE = 6–11% and IOA = 0.70–0.94) was identified in the model. Afterward, the LARS-WG model generated the baseline (2000–2014) based on the weather data at the sites and projected the models for the near (2030–2049) and remote future (2050–2070). The models revealed that not only the average maximum and minimum temperatures will rise by 1.85 °C and 1.62 °C which will exacerbate the reference evapotranspiration (ET 0 ), but also the precipitation and solar radiation will reach + 58%, and + 0.25 Mj m −2 . Our results clearly showed that precipitation volume over the growing seasons would elevate approximately two times as much as the baseline in the future, while there is a significant decrease in water productivity (WP) and yield from the intensive ET 0 . Based on the wheat simulation, the short-duration cultivar (Kalate) combined with the postponed planting (16-Dec) was determined as a practical alternative; nonetheless, both WP and yield significantly decreased by 40% and 7%, respectively ( p  < 0.05). In conclusion, identifying and analyzing future farming conditions (e.g., agro-climate, soil and crop management data) would provide a perception of the forthcoming scenarios. When applied, this knowledge can potentially mitigate the adverse impacts of climate change on global wheat production.

Camelina sativa (L.) is known as an important oilseed crop due to its application for biofuels, bio-products, and healthy food uses. However, it has a small seed (~ 0.7 × 1.5 mm), which can be a serious problem for plant establishment in some environments. Despite this, there is not enough information about this plant in response to edaphic (i.e., soil pH and burial depth) and abiotic environmental (i.e., temperature, water potential, salinity and light) factors. Our findings showed that all studied germination and emergence characteristics were affected by each of the environmental factors mentioned above. The cardinal temperatures were 1.50, 20.3 and 34.7 °C for the base, optimum and ceiling temperatures, respectively. The tolerance threshold values for salt and water potential stresses were 232 mM and − 1.29 MPa for seed germination, and 202 mM and − 0.75 MPa for the seedling emergence, respectively. There was no significant difference between the seeds germinated in the light and dark regimes. The maximum germination and seedling emergence were recorded at a pH range of 7–8 and a sowing depth of 0.5 cm. The results obtained in the present study could help camelina producers to effectively manage the production of this oilseed crop under stressful conditions. The models fitted here could be applied in simulating camelina growth.

Increasing the yield of oilseeds is considered an important plan and strategy in different countries such as Iran. With limited available arable land, boosting the cultivation of oilseeds should involve increasing per unit area. Therefore, narrowing the yield gap (YG) and optimizing agricultural practices/inputs can be the efficient strategies for improving food security and mitigating the environmental impacts of agriculture. For this purpose, the boundary line analysis (BLA) was integrated with the life cycle assessment (LCA) in this study to survey 301 soybean farms. BLA analysis calculated attainable yield and YG as 4437 and 1972 kg ha−1, respectively. According to the results, the BLA improved the efficient use of resources and attenuated environmental hazards by exploring the causes of YG and optimizing farm practices, something which was confirmed by the LCA and the ReCiPe2016 model. For instance, optimization of nitrogen, phosphorus, potassium, and sulfur fertilizers resulted in reduction rates of 44%, 45%, 87%, and 56% the in global warming potential, respectively. As a result of the BLA-optimized tillage operations, the impacts of mineral resource scarcity and freshwater eutrophication were reduced by 15% and 16%, respectively. In addition, a reduction rate of 52% was also observed in the water use impact category due to the optimal irrigation frequencies, i.e., 1–3 times. Moreover, diesel fuel and fertilizers are the primary sources of environmental damage. Eventually, tillage optimization and fertilization should be first taken into account in order to produce larger amounts of healthier food by bridging the YG.

Salinity is the most prevalent abiotic stress faced by plants. Crop improvement can be achieved using genetic diversity. Therefore, this study aimed to identify relative salinity tolerant varieties among five rice mutant genotypes, which were screened between 100 genotypes through fundamental germination and seedling evaluations. The experiment was conducted as split-plot arrangement based on a randomized complete block design with four replications. The treatments consisted of salinity levels (0, 45, 75 mM) as the main plot and mutant genotypes (Tarom Hashemi1 (TH-1), Tarom Hashemi2 (TH-2) and Tarom Hashemi3 (TH-3), Tarom Chaloosi (TC), and Nemat (N)) as subplots. Thirty-day-old rice seedlings were transferred to the plots. One week later, all genotypes were exposed to salinity stress. There has been a positive and significant correlation between shoot dry weight, catalase, and guaiacol peroxidase; in contrast, a significantly negative correlation was observed between shoot dry weight and malondialdehyde. The chlorophyll a and carotenoid contents significantly reduced under salinity, except for TC; while proline, catalase content, and root Na+/K+ ratio increased in all rice genotypes. The lowest and the highest malondialdehyde content was recorded in TC and TH‑1 under 75 mM, respectively. Overall, more salt-tolerant plants showed osmotic adaptation mechanisms by activating antioxidant enzymes, whereas MDA increased in sensitive cultivars. Furthermore, principal component analysis based on salinity tolerance indexes distinguished that TC could be a more tolerant genotype compared with others. Overall, this salt-tolerant genotype could be selected to develop salt-tolerant rice varieties with high yields in the future.