Salt accumulation can degrade soil properties, decrease its productivity, and harm its ecological functions. Introducing salt-tolerant plant species associated with arbuscular mycorrhizal fungi (AMF) can act as an effective biological method for restoring salinized soils. AMF colonize plant roots and improve their nutrient acquisition capacity. However, there is limited knowledge on how AMF affects the production of signaling molecules, e.g., abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA), related to plant-microbe interactions under salinity. Here, we assess the potential benefits of the AMF Rhizophagus intraradices in enhancing plant growth and nutrient uptake in addition to modulating stress hormone signaling levels (ABA, SA, and JA) of the facultative halophyte Sulla carnosa under saline conditions. Plants were grown in pots filled with soil and irrigated with 200 mM NaCl for 1 month. AMF symbiosis substantially increased the shoot dry weight (+107%), root dry weight (+67%), photosynthetic pigment content (chlorophyll a, chlorophyll b, and carotenoids), and nutrient uptake (C, N, P, K, Cu, and Zn) while significantly limiting the increase in the shoot Na+ concentration and H2O2 content caused by salinity stress. Mycorrhizal symbiosis significantly enhanced the root and shoot SA levels by 450% and 32%, respectively, compared to the stressed non-inoculated plants, potentially contributing to enhanced systemic resistance and osmotic adjustment under saline conditions. Salt stress increased the shoot ABA content, especially in R. intraradices-inoculated plants (113% higher than in stressed non-mycorrhizal plants). These findings confirm that AMF mitigated the adverse effects of salinity on S. carnosa by increasing the SA and ABA levels and reducing oxidative damage.

Trichomes play a key role in both heavy metal tolerance and herbivory defense, and both stressors have been shown to induce increased trichome density. However, the combined effect of these stressors on trichome density in general, and specifically on metal-hyperaccumulating plants, has yet to be examined. The aim of this study was to test the effect of cadmium availability and herbivory on leaf trichome density and herbivore deterrence in the metal hyperaccumulator Helianthus annuus. To test this, H. Annuus plants were grown in control pots or pots inoculated with 10 mg/kg cadmium and were subjected to either no herbivory or simulated herbivory using mechanical damage and foliar jasmonic acid application. Herbivore deterrence was tested in a feeding assay using Spodoptera littoralis caterpillars. Interestingly, while the trichome density of H. annuus increased by 79% or 53.5% under high cadmium availability or simulated herbivory, respectively, it decreased by 26% when the stressors were combined. Furthermore, regardless of cadmium availability, simulated herbivory induced a 40% increase in deterrence of S. littoralis. These findings suggest that the combination of metal availability and herbivory might present excessive stress to hyperaccumulators. Moreover, they suggest that the risk of metal bioaccumulation in phytoremediation can be reduced by simulated herbivory.

The pollution of heavy metals (HMs) is a major environmental concern for agricultural farming communities due to water scarcity, which forces farmers to use wastewater for irrigation purposes in Pakistan. Vegetables grown around the cities are irrigated with domestic and industrial wastewater from areas near mining, paint, and ceramic industries that pollute edible parts of crops with various HMs. Cadmium (Cd) is an extremely toxic metal in arable soil that enters the food chain and damages the native biota, ultimately causing a reduction in plant growth and development. However, the use of microbes and growth regulators enhances plant growth and development as well as HM immobilization into the cell wall and hinders their entry into the food chain. Thus, the integrated use of bacterial consortium along with exogenously applied jasmonic acid (JA) mitigates the adverse effect of metal stress, ultimately reducing the metal mobility into roots by soil. Therefore, the current study was conducted to check the impact of Cd-tolerant bacteria and JA on the growth, nutrient status, and uptake of Cd in the cauliflower (Brassica oleracea). Our results demonstrated that increasing concentrations of Cd negatively affect growth, physiological, and biochemical attributes, while the use of a bacterial consortium (SS7 + SS8) with JA (40 mu mol L-1) significantly improved chlorophyll contents, stem fresh and dry biomass (19.7, 12.7, and 17.3%), root length and root fresh and dry weights (28.8, 15.2, and 23.0%), and curd fresh and dry weights and curd diameter (18.7, 12.6, and 15.1%). However, the maximum reduction in soil Cd, roots, and curd uptake was observed by 8, 11, and 9.3%, respectively, under integrated treatment as compared to the control. Moreover, integrating bacterial consortium and JA improves superoxide dismutase (SOD) (16.79%), peroxidase dismutase (POD) (26.96%), peroxidase (POX) (26.13%), and catalase (CAT) (26.86%). The plant nitrogen, phosphorus, and potassium contents were significantly increased in soil, roots, and curd up to 8, 11, and 9.3%, respectively. Hence, a consortium of Klebsiella strains in combination with JA is a potential phytostabilizer and it reduces the uptake of Cd from soil to roots to alleviate the adverse impact on cauliflower's growth and productivity.

The remediation of soil contaminated with cadmium (Cd) and arsenic (As) has consistently been a complex issue. Foliar application of jasmonic acid (JA) could be a promising agronomic practice for reducing heavy metal accumulations. However, the combined reduction effects and mechanisms of Cd and As in rice through foliar JA application have not been fully explored. In this study, a pot experiment was conducted to investigate rice yield, Cd and As accumulations and translocations, photosynthesis, and ROS-scavenging attributes in Huanghuazhan (HHZ) and Huarun No.2 (HR). The results revealed that 1 mu M JA treatment significantly decreased the concentrations of Cd (by 34.6% in HHZ and 38.3% in HR) and As (by 30.8% in HHZ and 40.8% in HR) in the grains, and increased the percentage of filled-grain and 1000-grain weight in HHZ. The structural equation model (SEM) indicated that grain Cd was directly and positively affected by panicle Cd and leaf sheath Cd, while grain As was directly and positively affected by panicle As, leaf blade As and leaf sheath As. JA application enhanced the net photosynthetic rate and chlorophyll content (both a and b). Additionally, it scavenged levels of H2O2 and O2.-, reduced lipid peroxidation damage by promoting the activities of antioxidant enzymes and altering the cellular redox status in the flag leaves of rice. Overall, these results suggest that foliar JA application of could be an effective strategy for preventing Cd and As accumulations in rice grains in paddy soils with low to medium contamination risks.

In recent years, alkaline soda soil has stimulated numerous biological research on plants under carbonate stress. Here, we explored the difference in physiological regulation of rice seedlings between saline (NaCl) and alkaline carbonate (NaHCO3 and Na2CO3) stress. The rice seedlings were treated with 40 mM NaCl, 40 mM NaHCO3 and 20 mM Na2CO3 for 2 h, 12 h, 24 h and 36 h, their physiological characteristics were determined, and organic acid biosynthesis and metabolism and hormone signalling were identified by transcriptome analysis. The results showed that alkaline stress caused greater damage to their photosynthetic and antioxidant systems and led to greater accumulation of organic acid, membrane damage, proline and soluble sugar but a decreased jasmonic acid content compared with NaCl stress. Jasmonate ZIM-Domain (JAZ), the probable indole-3-acetic acid-amido synthetase GH3s, and the protein phosphatase type 2Cs that related to the hormone signalling pathway especially changed under Na2CO3 stress. Further, the organic acid biosynthesis and metabolism process in rice seedlings were modified by both Na2CO3 and NaHCO3 stresses through the glycolate/glyoxylate and pyruvate metabolism pathways. Collectively, this study provides valuable evidence on carbonate-responsive genes and insights into the different molecular mechanisms of saline and alkaline stresses.

This study, focusing on porous sheet mulching cultivation for high -quality and annual steady production of Satsuma mandarin, investigated trees photosynthetic oxidation stress according to the soil moisture in the porous mulching cultivation. Leaf, vesicle tissue water status, chlorophyll fluorescence, plant hormone abscisic acid (ABA) and jasmonic acid (JA) activity were measured using a phychrometer sample chamber, potable fluorescene meter and UHPLC and MS/MS were measured. Leaf water potential fluctuated according to the change in soil moisture content between the non -sheet mulching (control) and restoring the porous sheet (mulching) groups throughout this experiment period, and about 2 weeks intervals drip irrigation after the mulching (Mul. + Drip). In September, the leaf water potential of the control (-0.9 similar to -1.3 MPa) was higher than that of the mulching (-2.5 similar to -2.7 MPa), and Mul. + Drip (-2.2 similar to -2.3 MPa) groups. In October, due to continuous dry weather, the results of control and mulching were -3.0 MPa and -4.0 MPa or below respectively, which were lower than Mul. + Drip (-2.64 MPa). The water potential of vesicle tissue also fluctuated similarly to that of the leaf water potential. The osmotic potential was tendentially higher in the control than that in mulching and Mul. + Drip group. The turgor pressure remained constant at 0.5 MPa in October and November except for the time in September. The soluble solids content (SSC) of fruit at harvest was higher at 14.55 degrees Brix in the mulching and 13.96 degrees Brix in the Mul. + Drip, which were both higher than 11.05 degrees Brix in the control, showing a significant difference and confirming a rise in the SCC caused by osmotic control. The degree of oxidative damage according to water stress level caused by drought stress was investigated by the comparison of the maximum quantum efficiency value of (Fv/Fm), the initial fluorescence value (Fo) value, and the change in photosynthetic rate. The concentration of ABA in the leaf, fruit peel, and flesh was relevant to the leaf moisture stress and fruit sugar content. The concentration of JA varied as the concentration of ABA changed. In conclusion, Fv/Fm and Fo of chlorophyll PSII and ABA regarding photosynthetic oxidative damage were found to be indicators of the degree of damage according to tree water stress levels.