Lithium (Li), as an emerging environmental contaminant, can disrupt plant physiological processes, underscoring the importance of investigating tolerant species to identify suitable candidates for restoring contaminated soils. This study assessed the impact of Li₂CO₃ and Li₂SO₄ (0, 50, 150, 250 mM) on seed germination and early growth of two drought-tolerant Scrophularia striata ecotypes, Lizan and Pahleh. Measured parameters included germination rate, final germination percentage (FGP), mean germination rate (MGR), germination index (GI), coefficient of velocity of germination (CVG), germination rate index (GRI), first and last germination time (FDG, LDG), time spread of germination (TSG), Timson index (TGI), seedling vitality index (SVI), seedling, root, and stem length, as well as fresh and dry weight. The Pahleh ecotype showed strong resistance to both Li forms at 50 and 150 mM, with a significantly higher MGR than the control at these concentrations. The Lizan ecotype maintained higher growth under Li stress, while Pahleh seedlings were about two times shorter under Li₂SO₄ and 1.5 times shorter under Li₂CO₃, indicating the superior Li tolerance of Lizan. The Pahleh ecotype showed no significant biomass change between the control and some Li concentrations. At 150 mM Li₂CO₃, the Pahleh ecotype showed no significant change in germination, indicating high Li tolerance. Li form and concentration influenced tolerance and growth in both ecotypes. S. striata, especially Lizan, appears suitable for Li-contaminated arid lands.

Small-scale forest owners frequently implement thinning to enhance stand productivity, improve timber quality, and maintain structural diversity; however, its short-term effects on soil physicochemical and biological properties remain insufficiently understood. This study evaluated the short-term effects of moderate thinning on selected soil physicochemical properties, microbial indicators, and wood decomposition by comparing adjacent thinned and unthinned spruce stands in southern Sweden. Soil moisture, pH, bulk density, organic carbon (OC), total nitrogen (N), mineral N forms, cation exchange capacity (CEC), major nutrients, microbial biomass indicators, and wood decomposition were assessed. Two years after thinning, no significant differences were detected in bulk soil physicochemical properties, nutrient pools, or carbon stocks between the stands, suggesting limited short-term effects on soil fertility and carbon storage. In contrast, wood decomposition rates and microbial biomass nitrogen (MBN) were significantly higher in the thinned stand, indicating an early biological response to thinning despite no significant differences in total microbial, fungal, or bacterial biomass. Pearson correlation analysis further revealed significant associations between MBN and several soil physicochemical properties, highlighting the close linkage between microbial N dynamics and soil conditions. Overall, the findings suggest that moderate thinning had limited short-term effects on bulk soil properties but stimulated wood decay processes and microbial N-immobilization. Given the short monitoring period and the case-study nature of this work, the results should be interpreted with caution, and long-term studies across replicated stands are needed to evaluate the persistence of these responses and their implications for forest soil functioning.

Soil organic matter fractions (labile and non-labile) and biological properties are robust indicators for soil quality and widely used as key metrics of soil health, consistent with their role in terrestrial nutrient cycling. Despite extensive research on the effects of forest degradation and conversion to rangeland on soil properties, little is known about soil health indicators in this context in semi-arid mountainous regions. To address this knowledge gap, we sampled litter and soil in a rangeland area four and 15 years (in 2009 and 2024, respectively) after forest degradation and rangeland formation in the semi-arid mountainous region of northern Iran. Simultaneously, litter and soil samples were also collected in adjacent forest areas (as controls). The transformation of forests into rangelands resulted in a substantial reduction in soil organic matter fractions and biota populations. Deforestation increased soil greenhouse gas emissions in the study area, especially in the summer season. Our findings show a decrease in soil health indicators in the order of forest (2024) > rangeland (2024) > forest (2009) > rangeland (2009). Overall, our results indicate that although some soil regeneration occurs after the loss of primary forests and the establishment of secondary vegetation, constraints inherent to semi-arid mountainous environments make secondary vegetation far less effective than primary vegetation in restoring soil functions. Therefore, the restoration of forests degraded by native species should be high up on the agenda of land managers to recover soil health and safeguard soil-related ecosystem services.

This study delves into the intricate environmental ramifications of desalination brine on mangrove seedlings (Avicennia marina Forssk. Vierh), encompassing an extensive examination of plant growth, biomass allocation, soil salinity, leaf elemental composition, and plant biochemical reactions. Seedling propagules were collected from robust grey mangrove trees in Tiabe, Minab port, South of Iran, and planted in plastic pots in September 2020. Following irrigation twice daily, treatments with desalination brine concentrations (0%, 1%, 2%, 3%, 5%, 10%, and 20%) were applied for 6 months. The results reveal that seedling height and diameter remain stable up to 3% brine but exhibit declines at higher concentrations. Leaf area remains unaffected at 1–3% brine but experiences a significant decrease beyond 5%. Seedling vitality sharply declines at 1%, intensifying up to 10%, with the most profound reduction at 20% brine concentration. Biomass allocation in roots, shoots and leaves demonstrates nuanced responses, with soil salinity increasing significantly, particularly at the highest brine concentration of 20%. Sodium and chloride concentrations exhibit tissue-specific variations, and a positive correlation is observed between cadmium concentrations and brine intensity. The study underscores a pollution-induced stress on photosynthetic pigments. Enzyme activities (CAT, POD, SOD) show an escalating trend with brine, peaking at 20%, emphasizing the intricate environmental implications of desalination brine on coastal ecosystems. The findings advocate for sustainable management practices in coastal ecosystems facing anthropogenic stressors.

This study aims to explore the salt tolerance mechanisms of Avicennia marina from the Persian Gulf, addressing the gap in understanding whether mangroves are facultative or obligatory halophytes. Seedlings were exposed to freshwater (control), low salinity (25% seawater), medium salinity (50% seawater), and high salinity (100% seawater) treatments for six months. The results revealed that medium salinity promoted optimal growth, with the highest values for plant height, root and shoot biomass, leaf area, and seedling vigor (2.86%). The non-salinity treatment showed lower vigor (1.96%) and greater leaf loss (17.96%). Medium salinity increased nitrogen and potassium levels, while high salinity elevated chloride and sodium content. Photosynthetic pigments were higher in moderate and low salinity treatments, and catalase activity peaked in freshwater, with peroxidase activity highest in both freshwater and high salinity treatments. These findings provide evidence that A. marina from the Persian Gulf is a facultative halophyte, capable of thriving in both saline and non-saline conditions, with salinity enhancing its growth and health.

Crown dieback of oak is a critical issue in arid and semi-arid regions, threatening forest sustainability and biodiversity. This study explores the biochemical responses of Persian oak trees under varying health conditions to uncover the mechanisms driving oak decline. Key parameters such as photosynthetic pigments, antioxidant enzyme activities, osmolyte accumulation, and oxidative stress markers were analyzed. Despite stable photosynthetic pigments in both healthy and declining trees, catalase and peroxidase antioxidant enzyme levels were significantly higher in declining trees, highlighting their role in mitigating oxidative damage. Proline accumulation emerged as a vital osmoprotectant, while malondialdehyde (MDA) levels reflected heightened lipid peroxidation and oxidative stress. Principal Component Analysis (PCA) further differentiated healthy and declining trees, identifying antioxidant activity as a significant factor. These findings provide valuable insights into Persian oak resilience, offering a foundation for early detection of decline and sustainable management practices to mitigate the effects of climate change on oak forests.

This study examined the phytochemical diversity, antioxidant capacity, and genetic relationships among Papaver species collected from western and central Iran. Significant interspecific and regional variation was observed in total phenolic and flavonoid contents, with P. hybridum from Khuzestan showing the highest phenolic (50.26 mg GAE/g DW) and antioxidant activity (DPPH: 70.40%, FRAP: 6.91 mu mol Fe-2+/g DW). P. macrostomum and P. dubium also exhibited notable flavonoid and anthocyanin levels, respectively. Codeine content peaked in P. hybridum, while papaverine was highest in P. dubium. Antioxidant traits correlated strongly with phenolic content and environmental variables such as humidity and elevation. PCA revealed clustering of antioxidant traits, while alkaloids and anthocyanins formed distinct patterns. Phylogenetic analysis indicated complex evolutionary relationships and possible introgression among species. These findings highlight substantial phytochemical and genetic variation shaped by local environments. As this study focuses on Iranian populations, broader geographic sampling is needed to generalize the patterns observed.

In many developing countries, landfilling is widely used as an efficient method for disposing of municipal solid waste. Literature review reveals that knowledge regarding the effects of climatic factors such as temperature and precipitation on different landfill sites is still insufficient and fragmented, especially in forest ecosystems. Therefore, this study sought to examine how waste accumulation affects soil health under different climatic conditions in the north of Iran. Soil samples were collected from four distinct sites that show a decline in precipitation alongside a rise in air temperature: Chalous, Noor, Shirgah, and Behshahr. Soil sampling across the 4 sites was performed in 2 environmental conditions (forest landfill and forest stand as a control), 4 seasons (spring, summer, fall, and winter), 3 soil depths (0-10 cm, 10-20 cm, and 20-30 cm), with 20 sampling replications taken at distances ranging from 200 to 300 m from each other. Soil sampling was done exactly at the waste dump site and after discarding the waste. Our results indicated that landfills led to a decline in litter chemical properties. In addition, landfills reduced soil porosity, aggregate stability, and soil fertility (nearly 1-2 times more in Chalous forest stand with higher precipitation and lower temperatures). Notably, the concentrations of heavy metals, such as cadmium, lead, and zinc significantly increased in landfill areas compared to the forest stand. Additionally, populations of fungi, bacteria, collembola, nematodes, acarina, protozoa have also decreased in all landfill sites. Furthermore, microbial parameters such as respiration, microbial biomass of C, N, and P, have declined following the climate pattern from Chalous to Behshahr in all the landfill sites, which were 1.5-2 times higher in Chalous forest stand with higher precipitation and lower temperatures than the other sites. Our findings highlight that unengineered landfilling had negative effects on soil health indicators at all sites studied, however, the region with the driest climate and least fertile soil suffered the most severe impacts. As a recommendation, municipalities can create targeted approaches, including waste recycling programs, that aim to mitigate risks and negative impacts while improving the overall benefits of landfills from a life-cycle perspective, addressing the needs of different stakeholders.