Stresses, Volume 4, Issue 1 (March 2024) – 11 articles

Salinity and metal stress are significant abiotic factors that negatively influence plant growth and development. These factors lead to diminished agricultural yields on a global scale. Organic amendments have emerged as a potential solution for mitigating the adverse effects of salinity and metal stress on plants. When plants experience these stresses, they produce reactive oxygen species, which can impair protein synthesis and damage cellular membranes. Organic amendments, including biochar, vermicompost, green manure, and farmyard manure, have been shown to facilitate soil nitrogen uptake, an essential component for protein synthesis, and enhance various plant processes such as metabolism, protein accumulation, and antioxidant activities. Researchers have observed that the application of organic amendments improves plant stress tolerance, plant growth, and yield. They achieve this by altering the plant’s ionic balance, enhancing the photosynthetic machinery, boosting antioxidant systems, and reducing oxidative damage. The potential of organic amendments to deal effectively with high salinity and metal concentrations in the soil is gaining increased attention and is becoming an increasingly popular practice in the field of agriculture. This review aims to provide insights into methods for treating soils contaminated with salinity and heavy metals by manipulating their bioavailability through the use of various soil amendments. Full article

The aim of this study was to investigate the morpho-physiological responses of tomato and bell pepper plants when specific nutrients were restricted. The study was conducted in a greenhouse under controlled environmental conditions and used hydroponic solution as the growth medium, with the nutrient solution being replaced as needed. Treatments consisted of a control treatment that included all nutrients at optimal concentrations and the suppression of magnesium (Mg), boron (B), zinc (Zn), and iron (Fe) for both tomato and bell pepper. The experimental design followed a completely randomized design, with a 2 (crops) × 5 (treatments) factorial scheme replicated four times. The results of this study showed that suppression of Fe had the most pronounced negative effect on the morphology and physiology of tomatoes and bell peppers and caused a reduction in parameters associated with gas exchange, leading to the development of interveinal chlorosis in the leaves. The suppression of Mg had the second most notable negative effects, with similar deficiency symptoms observed in the plant leaves as observed for the absence of Fe. While the suppression of B and Zn were less prominent compared to Fe and Mg, they still resulted in tissue malformation in the shoot apices and reductions in gas exchange and negatively impacted the morphological parameters evaluated. Therefore, our study provided important insights on how Mg, B, Zn, and Fe depletion affects tomato and bell pepper physiology and its impacts on tomato and bell pepper morphology. Full article

Yeast recycling, which is a common practice in sugarcane ethanol plants, could be expanded if it could be successfully implemented in corn-based ethanol production. However, the process of recycling the yeast remaining after fermentation is hampered by contaminating microorganisms that reduce the fermentation efficiency and compete with the yeast for the fermentable sugars. Currently, antibiotics are used to control microbial contamination. This study proposes chlorine dioxide and electron beam irradiation as alternative control methods for completely inactivating contaminants and minimizing their effect on recycled yeast. For that, wort sterilization using electron radiation (20 kGy) and treatment with a chemical biocide, namely chlorine dioxide (125 mg kg⁻¹), were compared with non-treated wort. Five fermentation cycles were performed using fed-batch systems with 300 g L⁻¹ of fermentable sugars. The results obtained in this study showed the inactivation of contaminants under the effect of electron beam irradiation, which led to an increase in the productivity, yield, and efficiency of fermentation by 0.21 g L⁻¹h⁻¹, 2.6%, and 4.7%, respectively. However, ClO₂ did not show promising results in reducing contamination or improving fermentative parameters. Thus, electron beam irradiation of contaminated wort may be a suitable alternative to chemical biocides and would allow the use of recycled yeast in corn-based ethanol plants. Full article

Due to the oncoming climate changes, various environmental stresses (drought, salinity, heavy-metals, low or high temperatures, etc.) might dramatically affect crop yields and the quality of produced foods. Therefore, to meet the growing food demand of the human population, improvement of stress tolerance of the currently cultured crops is required. The knowledge of the molecular underlying mechanisms provides a versatile instrument to correct plant metabolism via chemical tools and to thereby increase their adaptive potential. This will preserve crop productivity and quality under abiotic stress conditions. Endogenously produced nitric oxide (NO) is one of the key signaling factors activating stress tolerance mechanisms in plants. Thus, the application of synthetic NO donors as stress-protective phytoeffectors might support maintaining plant growth and productivity under stressful conditions. Sydnone imines (sydnonimines) are a class of clinically established mesoionic heterocyclic NO donors which represent a promising candidate group for such phytoeffectors. Therefore, here, we provide an overview of the current progress in the application of sydnone imines as exogenous NO donors in plants, with a special emphasis on their potential as herbicides as well as herbicide antidotes, growth stimulants and stress protectors triggering plant tolerance mechanisms. We specifically address the structure–activity relationships in the context of the growth modulating activity of sydnone imines. Growth stimulating or antidote effects are typical for 4-α-hydroxybenzyl derivatives of sydnone imines containing an alkyl substituent in position N-3. The nature of the substituent of the N-6 atom has a significant influence on the activity profile and the intensity of the effect. Nevertheless, further investigations are necessary to establish reliable structure–activity relationships (SAR). Consequently, sydnone imines might be considered promising phytoeffector candidates, which are expected to exert either protective effects on plants growing under unfavorable conditions, or herbicidal ones, depending on the exact structure. Full article

In recent years, the adoption of sustainable pest management strategies has increased interest in the utilization of biopesticides, with a focus on harnessing beneficial microorganisms. Among these, lipopeptides, such as surfactins, iturins, and fengycins produced by the genus Bacillus, have gained significant attention due to their multifaceted biocontrol mechanisms and wide-ranging inhibitory effects. This review aims to address the regulation, biosynthesis, and production of three main lipopeptide families secreted by the genus Bacillus, as well as the identification and quantification analysis used to date, through the omic tools approach. The three families have been identified as key contributors to the biocontrol abilities of these bacteria, with their broad-spectrum activity making them valuable tools in integrated pest management approaches that aim to reduce reliance on chemical pesticides use while maintaining crop health and productivity. Full article

The production of seedlings is one of the main activities for implementing agricultural crops. Many factors are involved in producing quality seedlings, including nutrition, health, genetics, and climatic factors such as temperature, humidity, and light. To evaluate the effect of light supplementation, a study was conducted using supplementary artificial light to produce lettuce and cauliflower seedlings. Sowing was carried out in styrofoam trays under a floating irrigation system. Part of the experiment containing the two species, received treatment with LED light for an additional 4 h per day, in addition to solar radiation (10 h∙day⁻¹). The remaining seedlings received only solar radiation (without supplementation). After 37 days, the seedlings’ biometric (leaf area, root length, aerial dry mass, and root dry mass) and biochemical parameters (phenolic compounds, flavonoids, chlorophyll a/b, and total chlorophyll) were analyzed. The data showed that the complementary light enhanced the performance in all the biometric parameters evaluated in the experiment for lettuce and cauliflower. The biochemical parameters in lettuce were also higher in seedlings with light supplementation. For cauliflower, supplementary light did not differ from the natural photoperiod for biochemical parameters except for a reduction in the levels of total phenolic compounds. Considering the enhanced biometric and biochemical parameters and greater dry weight and leaf area of the seedlings grown with supplemental light, using such a tool can optimize seedling development, possibly reducing production time in the nursery and providing greater productivity. Full article

Plants have long been valued for their medicinal and nutritional contributions to human life. Anacyclus pyrethrum, a member of the Asteraceae family, has attracted increasing attention as a source of natural products with diverse applications. In this study, we explored the toxicity and pharmacological properties of the aqueous extract of A. pyrethrum (AEAP). The acute toxicity study involved groups of mice subjected to oral administration of varying doses of AEAP, with immediate post-administration observations to detect any signs of toxicity or mortality. Comprehensive biochemical and hematological analyses encompassed assessments of renal function. The pharmacological profile was assessed by evaluating antinociceptive, anxiolytic, and antidepressant effects, which were measured using the hot plate test, elevated plus maze, open field test, and forced swim test, respectively. Different doses (100, 200, 400, and 800 mg/kg) were administered to rats via gavage for this assessment. The results revealed that the acute toxicity demonstrated the safety of AEAP at the tested doses, with no observed mortality or significant alterations. Moreover, it revealed that AEAP possesses an LD₅₀ value greater than 5000 mg/kg. The pharmacological properties of AEAP demonstrated anxiolytic and antidepressant activities at a dose of 200 mg/kg, while no antinociceptive effect was observed. These findings underscore the potential of A. pyrethrum as a natural source of bioactive compounds with therapeutic applications. Further research is needed to explore long-term and chronic effects for a comprehensive assessment. Full article

Thyroid Eye Disease (TED) is a debilitating autoimmune condition characterized by significant inflammation of orbital tissues, including the extraocular muscles and adipose tissues. The pathological mechanisms underlying this inflammation involve a complex interplay of stress responses at the cellular and molecular level. This review aims to critically evaluate and synthesize existing literature on the mechanisms of orbital inflammation in TED. We discuss the role of autoantibodies, cytokines, and reactive oxygen species (ROS) in the initiation and propagation of the inflammatory process. Additionally, we explore how stress responses triggered by these elements affect the integrity of orbital tissues and contribute to its remodeling. Our review underscores the need for continued research in this field, which may pave the way for novel therapeutic strategies for TED. Full article

Ethylene, a gaseous phytohormone, is emerging as a central player in the intricate web of plant developmental processes from germination to senescence under optimal and stressed conditions. The presence of ethylene has been noted in different plant parts, including the stems, leaves, flowers, roots, seeds, and fruits. This review aims to provide a comprehensive overview of the regulatory impact of ethylene on pivotal plant developmental processes, such as cell division and elongation, senescence, abscission, fruit and flower development, root hair formation, chloroplast maturation, and photosynthesis. The review also encompasses ethylene biosynthesis and signaling: a snapshot of the regulatory mechanisms governing ethylene production. Understanding of the impact of ethylene’s regulatory functions on plant developmental processes has significant implications for agriculture, biotechnology, and our fundamental comprehension of plant biology. This review underscores the potential of ethylene to revolutionize plant development and crop management. Full article

In this study, a detailed phytochemical investigation of compounds in the twigs of the mistletoe Loranthus europaeus Jacq., which belongs to the Loranthaceae family, is presented. Specimens were collected from the mistletoe L. europaeus growing on oak trees in the mainland of Greece. The alliance of oaks and mistletoes became a symbol of knowledge and strength for many centuries. Although numerous compounds of aerial tissues of other mistletoes, e.g., Viscum album, have been published, few studies have been conducted to investigate the metabolic and physiological traits of the hemiparasitic, deciduous Loranthus europaeus. LC-HRMS-based analysis led to a detailed characterization of ethyl acetate and dichloromethane extracts of the twigs of L. europaeus, which, to the best of our knowledge, exhibit enhanced antioxidant potential. Hence, twenty-four and twenty-six compounds were tentatively identified from the ethyl acetate and dichloromethane twigs’ extracts, respectively; these compounds belong to fatty acids, flavonoids, and flavonoid glycosides. Also, chlorophyll, soluble sugar, starch, and lipid contents in the twigs of L. europaeus, which have not hitherto been published, were investigated. Full article

Alcohol is one of the most used legal drugs abused worldwide, and its consumption is associated with high mortality and morbidity rates. There is an increasing concern about the starting age of consumption of this drug since it has become evident that it is at younger ages. The so-called “pattern of consumption by binge” corresponds to ingesting large amounts of alcohol in a short period and is the most popular among young people. Previous studies show that alcohol causes damage in different areas, such as the hippocampus, hypothalamus, and prefrontal cortex, and adolescents are more susceptible to alcohol toxicity. Alcohol inhibits the membrane glutamate receptor, NMDA-type glutamate receptors (NMDAR). Using a binge-like alcohol administration protocol in adolescent rats (PND25), we investigate decision making through the attentional set-shifting test (ASST) and alterations in the NMDAR signaling in related areas. We observe an impairment in executive function without alterations in NMDAR abundance. However, binge alcohol changes NMDAR signaling and decreases quantity in the synapse, mainly in the hippocampus and hypothalamus. We suggest that prefrontal cortex impairment could arise from damaged connections with the hippocampus and hypothalamus, affecting the survival pathway and memory and learning process. Full article