Halophytic Plants Research Articles

Salt Tolerance and Ion Accumulation in Several Halophytic Plant Species Depending on the Type of Anion

The question of the effect of the anion type on halophyte salt tolerance and ion accumulation is still far from the necessary generalization due to the lack of comparative studies. The aim of the present study was to compare the relatively long-term effect of treatment with various salts formed by different anions on the growth and ion accumulation of several halophyte species in controlled conditions. The main experiments with the largest variety of individual salt types were performed with Cochlearia officinalis L. and two cultivars of Limonium sinuatum (L.) Mill. In addition, experiments with Lobularia maritima (L.) Desv., Plantago maritima L., and Tripolium pannonicum (Jacq.) Dobrocz. focused on the comparison of neutral (NaCl) and alkaline (NaHCO3) salts as well as NaNO3. Acetate salts appeared to be the most toxic, with only Plantago and Tripolium plants being able to withstand full treatment while having a pronounced inhibition in growth. Only the two Limonium cultivars were more susceptible to treatment with alkaline salts in comparison to that with neutral salts. In treatments with alkaline salts, the ion accumulation potential was lower in comparison to plants treated with chlorides and nitrates. It can be concluded that the type of anion is a significant determinant of salinity tolerance and ion accumulation in halophytes, but a high genotype dependence of the responses makes it difficult to generalize the obtained results.

Effect of halophyte-based management in physiological and biochemical responses of tomato plants under moderately saline greenhouse conditions

Salinity, both in irrigation water and in soils, is one of the major abiotic constraints for agriculture activity worldwide. Phytodesalinization is a low-cost plant-based bioremediation strategy that can effectively amend salt-affected soils by cultivating salt tolerant plants. However, very few studies have evaluated the use of halophyte plants in crop management systems. In this work, we apply two different tomato crop management strategies involving the halophyte Arthrocaulon macrostachyum L. in a moderately saline soil: intercropping (mixed cultivation) and sequential cropping (cultivation of tomato where halophytes were previously grown). We investigated the effect of the different crop managements in some physiological and biochemical variables in tomato plants, including mineral nutrients content, photosynthesis, chlorophyll and flavonol contents, antioxidant metabolism and fruit production and quality. At soil level, both intercropping and sequential cropping decreased chloride content, sodium adsorption ratio and electrical conductivity, leading to reduced soil salinity. In tomato plants, halophyte-dependent management improved nutrient homeostasis and triggered a mild oxidative stress, whereas photosynthesis performance was enhanced by intercropping. In tomato fruits, the sequential cropping led to a 27% production increase and a slight decrease in the soluble sugar contents. We suggest the use of A. macrostachyum, and hence of halophyte plants, as an environmentally friendly phytoremediation strategy to improve plant performance while improving crop production, leading to a more sustainable agriculture and enhancing biodiversity.

In vitro Bioactivity of Halophytic Plant Heliotropium curassavicum L. against Selected Pathogens

Heliotropium curassavicum L. was screened for antimicrobial activity against some plant and human pathogens. Plant parts of H. curassavicum, were collected from mangrove habitats of Chollangi, near Kakinada, Plant parts are dried and extracts were obtained successfully with hexane, chloroform, methanol and water, by using Soxhlet extraction apparatus. The antimicrobial activity of the plant extracts on the various test organisms, including multiple antibiotic resistant bacteria were investigated. Antimicrobial activity of the extracts was determined by the Well Diffusion Method. The results concluded that the leaf and stem extracts of H. curassavicum possess antibacterial, antifungal activities. There is a possibility of developing this plant as a source of antibacterial and antifungal agent and further investigations are necessary to identify the bioactive principles.

Comparison of Halophyte and Glycophyte Plants from the Amaranthaceae-Chenopodiaceae Family in Their Ion-Exchange Properties of Polymeric Matrix of Cell Walls

Ion-exchanging properties of the polymeric matrix of the cell walls isolated from leaves were examined. The glycophyte 55-day-old plants of spinach (Spinacia oleracea L., cv. Matador) grown on a nutrient solution containing 0.5, 150, or 250 mM NaCl and the halophyte seepweed (Suaeda altissima (L.) Pall.) of the same age grown at 0.5, 250, or 750 mM NaCl were compared. The ion-exchange capacity of the cell walls was estimated at different pH and ionic strength of a solution. In the structure of the leaf cell walls, three types of cation-exchange groups were found, namely, two types of carboxylic groups (one of them belongs to galacturonic acid residue) and phenolic OH-groups. The quantities of the groups of each type and their ionization constants were determined. The qualitative composition of the ion-exchange groups in the leaf cell walls was found to be uniform in both plant species regardless of their nutrition. However, the quantity of the carboxylic groups of galacturonic acid depended on the ambient salt concentration in a different manner in the glycophyte and halophyte. This change in the composition of functional groups of cell wall polymers was more pronounced in the halophyte and is apparently one of the responses of these plants to salinization. The sharp increase in the NaCl concentration in the medium leads to a decrease in pH in the extracellular water space due to ion-exchange reactions between sodium ions coming from the external medium and protons of the ionized carboxylic groups of the cell walls. The results are discussed in the aspect of participation of the leaf cell walls in plant responses to salinization.

Phytochemical, antioxidant, and anticancer assessments of Atriplex halimus extracts: In silico and in vitro studies

In recent years, the global health community has become increasingly interested in harnessing the therapeutic potential of traditional plants. This study focuses on Atriplex halimus L., a halophytic plant known as Mediterranean saltbush or "Lgtef", traditionally heralded for its medicinal properties. Our primary objective was to scientifically validate its traditional use by examining the antioxidant and anticancer activities of two extracts: aqueous (AHAE) and hydroethanolic (AHHE) derived from its leaves. Both extracts demonstrated significant antioxidant capabilities when assessed through DPPH, BC, ABTS, IC, and TAC assays. Notably, AHHE exhibited exceptional potency, with a DPPH IC50 value of 0.59 ± 0.12 mg/mL. In anticancer evaluations against HepG2 and MDA-MB-463 cell lines, AHHE again stood out, indicating cytotoxic activity with IC50 values of 31.22 ± 3.19 µg/mL and 48.22 ± 2.03 µg/mL, respectively. These in vitro findings were bolstered by computational analyses, which confirmed the antioxidant and anticancer potential, highlighting AHHE's superior efficacy.In summary, our research affirms A. halimus as a rich source of natural bioactive agents, underscoring its traditional medicinal significance. By bridging indigenous knowledge with scientific validation, this study offers a promising avenue for future research into plant-derived remedies, especially against the backdrop of rising global cancer rates and challenges with synthetic drugs. Our findings underscore the therapeutic promise of A. halimus, emphasizing its potential as a cornerstone in life and health sciences.

Aromatic compounds depurative and plant growth promotion rhizobacteria abilities of Allenrolfea vaginata (Amaranthaceae) rhizosphere microbial communities from a solar saltern hypersaline soil

IntroductionThis work investigates whether rhizosphere microorganisms that colonize halophyte plants thriving in saline habitats can tolerate salinity and provide beneficial effects to their hosts, protecting them from environmental stresses, such as aromatic compound (AC) pollution.MethodsTo address this question, we conducted a series of experiments. First, we evaluated the effects of phenol, tyrosine, 4-hydroxybenzoic acid, and 2,4-dichlorophenoxyacetic (2,4-D) acids on the soil rhizosphere microbial community associated with the halophyteAllenrolfea vaginata. We then determined the ability of bacterial isolates from these microbial communities to utilize these ACs as carbon sources. Finally, we assessed their ability to promote plant growth under saline conditions.ResultsOur study revealed that each AC had a different impact on the structure and alpha and beta diversity of the halophyte bacterial (but not archaeal) communities. Notably, 2,4-D and phenol, to a lesser degree, had the most substantial decreasing effects. The removal of ACs by the rhizosphere community varied from 15% (2,4-D) to 100% (the other three ACs), depending on the concentration.Halomonasisolates were the most abundant and diverse strains capable of degrading the ACs, with strains ofMarinobacter,Alkalihalobacillus,Thalassobacillus,Oceanobacillus, and the archaeaHaladaptatusalso exhibiting catabolic properties. Moreover, our study found that halophile strains Halomonas sp. LV-8T andMarinobactersp. LV-48T enhanced the growth and protection ofArabidopsis thalianaplants by 30% to 55% under salt-stress conditions.DiscussionThese results suggest that moderate halophile microbial communities may protect halophytes from salinity and potential adverse effects of aromatic compounds through depurative processes.

Seed Germination and Seedling Growth in Suaeda salsa (Linn.) Pall. (Amaranthaceae) Demonstrate Varying Salinity Tolerance among Different Provenances.

Salinity is a pressing and widespread abiotic stress, adversely affecting agriculture productivity and plant growth worldwide. Seed germination is the most critical stage to seedling growth and establishing plant species in harsh environments, including saline stress. However, seed germination characteristics and stress tolerance may vary among geographical locations, such as various provenances. Suaeda salsa (Linn.) Pall. (S. salsa) is a halophytic plant that exhibits high salt tolerance and is often considered a pioneer species for the restoration of grasslands. Understanding the germination characteristics and stress tolerance of the species could be helpful in the vegetation restoration of saline-alkali land. In this study, we collected S. salsa seeds from seven different saline-alkali habitats (S1-S7) in the Songnen Plain region to assess the germination and seedling growth responses to NaCl, Na2CO3, and NaHCO3, and to observe the recovery of seed germination after relieving the salt stress. We observed significant differences in germination and seedling growth under three salt stresses and among seven provenances. Resistance to Na2CO3 and NaHCO3 stress was considerably higher during seedling growth than seed germination, while the opposite responses were observed for NaCl resistance. Seeds from S1 and S7 showed the highest tolerance to all three salt stress treatments, while S6 exhibited the lowest tolerance. Seeds from S2 exhibited low germination under control conditions, while low NaCl concentration and pretreatment improved germination. Ungerminated seeds under high salt concentrations germinated after relieving the salt stress. Germination of ungerminated seeds after the abatement of salt stress is an important adaptation strategy for black S. salsa seeds. While seeds from most provenances regerminated under NaCl, under Na2CO3 and NaHCO3, only seeds from S4 and S7 regerminated. These findings highlight the importance of soil salinity in the maternal environment for successful seed germination and seedling growth under various salinity-alkali stresses. Therefore, seed sources and provenance should be considered for vegetation restoration.

Antimicrobial Activity of Sesuvium portulacastrum (L.) Against Selected Pathogens

This work aims to evaluate the antimicrobial potential of halophytic plant, Sesuvium portulacastrum (L.) against, some plant and human pathogens. Plant parts of S. portulacastrum were collected from the mangrove habitats of Coringa Reserve Forest near Kakinada, Andhra Pradesh, India. Plant parts are dried and extracts were obtained successfully with hexane, chloroform, methanol and water, using Soxhlet extraction apparatus. Agar well diffusion method has been used to determine the antimicrobial activity of plant extracts against some gram positive bacteria (Bacillus subtilis, Bacillus megaterium and Lactobacillus acidophilus), gram negative bacteria (Escherichia coli, Enterobacter aerogenes, Enterobacter cloace and Klebsiella pneumonia) and fungal species (Candida albicans, Mucar recemosus, Rhizoctonia solani, Rhizopus stolonifer and Saccharomyces cerevisiae). The hexane, chloroform extracts showed minimum antimicrobial activity when compared to methanolic and water extracts. Water extract of S. portulacastrum showed appreciable antimicrobial activity against all bacterial and fungal strains. It reveals that this halophytic species has antimicrobial compounds which can act against microorganisms and they can be used in the treatment of infectious diseases caused by pathogenic microorganisms.

The Effects of Brackish Irrigation on Soil Ion Accumulation and Growth of Atriplex Species

Prolonged drought conditions in New Mexico have led growers to use brackish groundwater for crop irrigation. Desalination of the groundwater with reverse osmosis (RO) is possible, but the concentrated waste requires environmentally safe disposal, such as by irrigating native halophytic plants, Atriplex, which could be cultivated to feed livestock. We hypothesized that ions from the brackish irrigation would increasingly accumulate in the soil away from the roots as the wetting front expanded further from the emitter, while not affecting the aboveground growth of the plants. Atriplex species were irrigated with brackish water at two irrigation levels for three years. Soil samples were collected at the beginning, middle, and end of the study at two depths and three distances from the emitter. Electrical conductivity (EC), soil ion accumulation, and plant growth were recorded. The average EC of the soil increased with brackish water irrigation. As the ions accumulated along the wetting front of the percolating water rather than near roots, a favorable environment for root growth was provided. While sodic levels of ion accumulation were not reached in this study, aboveground growth still declined. This leads to the recommendation that RO-concentrated waste could be used to irrigate Atriplex species for livestock fodder, with further plans to irrigate with fresh water to remove accumulated ions as a potential sustainable waste management process. Additional studies are necessary to develop guidelines for Atriplex tolerance and harvesting.

Suaeda australis and its associated rhizosphere microbiota: a comparison of the nutrient removal potential between different shrimp farm sediments in New Caledonia.

Shrimp rearing generate organic waste that is trapped in the pond sediment. In excess, these wastes may impair aquaculture ecosystem and shrimps' health. To promote the biological oxidation of accumulated organic waste, the pond is drained and dried at the end of each production cycle. However, this practice is not always conducive to maintaining microbial decomposition activities in sediments. Shrimp production in New Caledonia is no exception to this problem of pollution of pond bottoms. One promising way of treating this waste would be bioremediation, using a native halophyte plant and its microbiota. Thus, this study explored the nutrient removal potential of Suaeda australis and its microbiota on sediments from four shrimp farms. Suaeda australis was grown in an experimental greenhouse for 6 months. In order to mimic the drying out of the sediments, pots containing only sediments were left to dry in the open air without halophytes. An analysis of the chemical composition and active microbiota was carried out initially and after 6 months in the sediments of the halophyte cultures and in the dry sediments for each farm, respectively. In the initial state, the chemical parameters and the microbial diversity of the sediment varied considerably from one farm to another. Growing Suaeda australis reduced the nitrogen, phosphorus and sulfur content in all type of sediment. However, this reduction varied significantly from one sediment to another. The rhizosphere of Suaeda australis is mainly composed of micro-organisms belonging to the Alphaproteobacteria class. However, the families recruited from this class vary depending on the farm in question. Depending on the sediment, the variation in microbiota leads to different putative biochemical functions. For two of the farms, a similar reduction in nitrogen concentration was observed in both dry and cultivated sediments. This suggests that certain initial chemical characteristics of the sediments influence the nutrient removal efficiency of Suaeda australis. Our study therefore highlights the need to control the pH of sediments before cultivation or in dry sediments in order to ensure optimal microbial decomposition of organic waste and nutrient cycling.

Antimicrobial Screening of the Solvent Extracts of Halophytic Plant Suaeda maritima (L.) Demort. Against Selected Pathogens

The antimicrobial activity of leaf and stem extracts of halophytic plant Suaeda maritima (L.) Demort. against, some plant and human pathogens. Plant parts of S. maritima were collected from the mangrove habitats of Pandi and Pora regions of Godavari estuary, near Amalapuram, Andhra Pradesh, India. Plant parts are dried and extracts were obtained successfully with hexane, chloroform, methanol and water, using Soxhlet extraction apparatus. The antimicrobial activity of the plant extracts on various test organisms including multiple antibiotic resistant bacteria were investigated by Well Diffusion Method under in vitro conditions. The plant extracts have shown promising antimicrobial activity against all tested organisms. Among the four extracts, water extract of S. maritima showed appreciable antimicrobial activity against all bacterial and fungal strains. It reveals that halophytic plant has antimicrobial compounds which can act against microorganisms and they can also be used in the treatment of infectious diseases caused by resistant pathogenic microorganisms.

Short-term changes in antioxidant response of Eutrema salsugineum exposed to severe salinity

Salinity is one of the major constraints limiting plant productivity. Understanding the mechanism of salinity tolerance is a necessary step for improving crops yield in saline conditions. Eutrema salsugineum is a halophyte species and plant model for salinity tolerance mechanism study. Therefore, we studied the ability of E. salsugineum plants for their antioxidant response to 400 mM NaCl treatment. Changes in hydrogen peroxide (H2O2), malondialdehyde (MDA) and tocopherol contents, and kinetics of catalase, superoxide dismutase and peroxidase enzyme activities were investigated. Results shows that, although increasing in the beginning of the salt treatment, the fast decrease in H2O2 and MDA levels afterwhile indicates the ability of E. salsugineum to alleviate oxidative damage and to maintain membrane integrity. Together, with the increase of tocopherol contents, the high enzymatic activity of CAT, SOD and POD reflect the highly efficient antioxidant response of E. salsugineum.

Translocation signatures of major elements in halophytes from hypersaline environments: the case study from Sečovlje Salina (Republic of Slovenia)

PurposeHypersaline environments are extremely vulnerable and important ecological niches. Because much knowledge has focused on the distribution of heavy metals in these areas, the detailed behavior of key major elements in hypersaline environments has not been elucidated in detail.This research aims to define the distribution, translocation pathways, and mobility patterns of the major elements in hypersaline sediments and halophytes.Materials and methodsSamples of Sarcocornia fruticosa plants were collected from evaporation (ES) and crystallization (CA) sites in the Sečovlje Salina area (Republic of Slovenia). The major element contents were measured by digestion in HNO3 then aqua regia and analyzed by ICP-MS for ultra-low detection limits. Rhizo-sediments from EA and CA were processed using sequential extraction analysis to determine the precise fractionation of Al, Ca, Fe, K, Mg, Mn, and Na. To determine the translocation patterns of individual major elements in S. fruticosa, two indices were calculated: bioconcentration (BCF) and translocation factor (TF). Differences and similarities between samples and elements were highlighted using Statistica VII and Grapher 8 statistical software and Ward’s method, respectively.Results and discussionThe obtained results confirmed that halophyte plants take up large amounts of the essential micronutrient Na due to high salinity, and that macronutrients (Ca, Mg, P, and S) are intensively translocated from the roots to the upper parts of the plant. The overall trend in translocation signature for major elements, distinguished by BCF and TF factor calculations, emphasizes that root tissues accumulate a significant amount of major elements and that accumulation depends on individual major elements. It also showed that the major elements Ca, Mg, Na, P, and S are highly translocated within plants, while the mobility of Al, Fe, and K is limited.ConclusionsOur results suggest that the major elements are vital macronutrients for halophytes, but their accumulation in the roots and further translocation within the plant depend on individual elements and their dynamics. The translocation pattern of the major elements can be justified as follows: Ca is an essential element for plant growth, maintenance, and membrane integrity; Mg is a specific component of chlorophyll; Na is present because of the hypersaline environment; P is a key component of plant metabolic processes; S represents an important component of enzymes and other key proteins; Al and Fe are preferentially accumulated in roots; and plant leaves are generally undersupplied with K. The presented results are of great importance for the general knowledge and use/application of halophytes in agriculture and biotechnology.

Is the Plant Bolboschoenus maritimus an Adequate Biomonitor for Trace Metal Contamination in Saltmarshes? A Field Study from the Óbidos Lagoon (Portugal)

Monitoring the negative impacts of trace metals is crucial to assess the health and stability of ecosystems. In salt marshes, halophyte plants were reported as possible bioaccumulators of these elements. The aim of this work was to explore the bioaccumulation potential of Bolboschoenus maritimus as a tool for monitoring the presence of metals in coastal environments. Bolboschoenus maritimus were collected from a brackish water lagoon, and the presence of the trace metals lead, cadmium, and nickel were seasonally evaluated in distinct parts of the plants, and in water and sediment samples. Lead was the trace metal with the highest concentration detected in water and sediments of the sampling site. The highest lead concentrations in B. maritimus were recorded in the spring season. The transport index indicated an accumulation of lead in the leaves of around 70% in the spring of 2009. Cadmium in leaves in spring and summer of 2009 reached values above 5 mg Cd. kg−1. Nickel was not detected in most samples collected. Bolboschoenus maritimus was considered an adequate biomonitor for lead and cadmium, since it bioaccumulates both metals with seasonally distinct results, as the bioaccumulation factor results indicated.

Isolation, screening, and characterization of plant growth enhancing endophytic bacteria from halophytic Heliotropium curassavicum L. collected from salt stress areas of Srikakulam, Andhra Pradesh

Farmers use excessive chemical fertilizers to boost crop productivity to meet growing agricultural demands. However, this practice is costly and environmentally hazardous. Sustainable increase in crop yield can be achieved through alternatives like microbial-based fertilizers. In the quest to identify plant growth-promoting endophytic bacteria, the present study was carried out and selected unexplored halophytic plant Heliotropium curassavicum L. Thirteen endophytic bacterial strains were isolated from both aerial and root portions of H.curassavicum. These isolates were tested for salt tolerance, enzyme production, and synthesis of growth-promoting secondary metabolites, like Indole-3-acetic acid (IAA) and phosphate solubilization . Most of the isolates belonged to the Bacillus family, exhibiting varying Gram staining and biochemical reactions. The majority are Gram-positive bacteria, non-motile, spore formers, and exist in two cells or chains. All isolates could tolerate up to 10% NaCl concentration and a temperature of 42°C. Based on phenotypic, bio-chemical characteristics, isolate HCR3 showed promising properties in synthesizing IAA and phosphate solubilization abilities. The isolate HCR3 grew well upto 10% NaCl concentration and also 42°C temperature. Based on molecular characterization by using 16S rRNA gene-based analysis HCR3 isolate was identified and belonged to the Genus Pseudomonas with the highest similarity index with Pseudomonas khazarica sp. HCR3 showed IAA production of 37µg ml-1, had a phosphate solubilization ability of 3.5 ppm, and recorded protease activity on gelatin medium. The findings highlight the potential of HCR3 and other strains from halophytic H. curassavicum L. to enhance plant growth through secondary bioactive metabolites, offering eco-friendly solutions for sustainable agriculture.

Effect of NaCl on the Lipid Profile of Detergent-Resistant membranes of the Chloroplasts and Mitochondria of Euhalophyte Plants

The effect of 1 M NaCl on the lipid profile of detergent-resistant chloroplast membranes was studied. sts and mitochondria of salt-accumulating halophyte plants – Salicornia perennans Willd. And Suaeda salsa (L.) Pall. (family Amaranthaceae). The composition of lipids and fatty acids in detergent-resistant membranes differs from the membrane lipids of chloroplasts and mitochondria by a large number of cerebrosides and sterols. Under the given salinity conditions, S. perennans experienced many a fold increase in the proportion of cerebrosides in the composition of detergent-resistant chloroplast membranes, and in S. salsa is found in detergent-resistant mitochondrial membranes. The opposite effect was observed in relation to sterols: a decrease in their relative content under the action of salt. Received data indicate the participation of detergent-resistant membranes in the interaction of chloroplast cells and mitochondria in the cellular response of halophytes to salinity.

Selection of Salinity-Adapted Endorhizal Fungal Consortia from Two Inoculum Sources and Six Halophyte Plants.

Soil salinity is a limiting factor in crop productivity. Inoculating crops with microorganisms adapted to salt stress is an alternative to increasing plant salinity tolerance. Few studies have simultaneously propagated arbuscular mycorrhizal fungi (AMF) and dark septate fungi (DSF) using different sources of native inoculum from halophyte plants and evaluated their effectiveness. In alfalfa plants as trap culture, this study assessed the infectivity of 38 microbial consortia native from rhizosphere soil (19) or roots (19) from six halophyte plants, as well as their effectiveness in mitigating salinity stress. Inoculation with soil resulted in 26-56% colonization by AMF and 12-32% by DSF. Root inoculation produced 10-56% and 8-24% colonization by AMF and DSF, respectively. There was no difference in the number of spores of AMF produced with both inoculum types. The effective consortia were selected based on low Na but high P and K shoot concentrations that are variable and are relevant for plant nutrition and salt stress mitigation. This microbial consortia selection may be a novel and applicable model, which would allow the production of native microbial inoculants adapted to salinity to diminish the harmful effects of salinity stress in glycophyte plants in the context of sustainable agriculture.

Colonization potential of endophytes from halophytic plants growing in the "Runn of Kutch" salt marshes and their contribution to mitigating salt stress in tomato cultivation.

Increasing soil salinity depreciates the quantity of the crop produce. Looking at the tremendous potential of plant-associated microorganisms in salinity stress mitigation, it would be very useful in exploring and deciphering salt-tolerant microorganisms from halophytic plants and their utilization in cultivated plants. With this aim, in the present study, four halophytic plants were taken from Rann of Kutch, and bacterial endophytes were isolated from different plant organs. These endophytes were characterized by plant growth and health promotion features. The molecular identification was done based on 16 s rRNA sequence similarity. It was found that the endophytic bacteria isolated from 4 different halophytes found sharing phylogenetic relatedness. Four potential endophytes Alkalihalobacillus gibsonii 2H2, Achromobacter insuavis 2H18, Terribacillus halophilus 2H20, and Bacillus siamensis 4H1 were tested in tomato for salinity stress alleviation. Changes in the levels of antioxidants were analyzed. Total chlorophyll, total phenolics, malondialdehyde, and proline content indicated reduced damage in the plant system due to salinity by the application of endophytes. All the treatments exhibited low levels of electrolyte leakage. The accumulation of enzymatic reactive oxygen species scavengers was assessed from the levels of peroxidase, catalase, superoxide dismutase, phenylalanine ammonia-lyase, ascorbate peroxidase, and guiacol peroxidase. The NBT and DAB staining confirmed the findings. The reduction in the accumulation of Na+ ions in tomato leaves was visualized using Sodium Green probes under CSLM and found to be lowest in Terribacillus halophilus 2H20 and Bacillus siamensis 4H1 inoculated plants. The endophyte Terribacillus halophilus 2H20 was the most promising isolate. The colonization in tomato roots was confirmed using a cell tracker system. Results showed that the endophytes were found to have salinity stress mitigation traits. The efficiency could be further improved with the combination of other endophytes tested earlier.

Paleoecology of the mammoth fauna of Southern Siberia during the last glacial period based on stable isotope data

Composition of stable carbon (δ13C) and nitrogen (δ15N) isotopes of bone collagen of large mammals who inhabited Southern Siberia during MIS2 have been analysed. The results suggest significant isotopic differences of those animals from the fauna of other regions. Notably, the differences between animals from neighbouring regions may be more significant than between those from more distant areas. A summary description of the isotopic signatures of the LGP mammoth fauna from the Minusinsk depression has been presented, showing a general pattern of lower δ15N and higher δ13C values as compared to species from other regions. Variations in δ15N values may be explained by strong influence of landscape and climatic factors, in particular, the highly mosaic nature of local landscapes due to its ruggedness and altitudinal zonation. One of the possible mechanisms that could explain the observed δ13C signatures in bone collagen of the mammals is regional geochemistry, namely, the presence of developed system of mineral lakes and saline soils in the area. On saline soils, halophytic plants using the C4 type of photosynthesis and characterized by higher δ13C values, are more common. Furthermore, some halophytes, being C3 plants, are able to adapt to salinity stress and fix carbon in a way similar to C4 plants.

ROS Homeostasis and Antioxidants in the Halophytic Plants and Seeds.

Reactive oxygen species (ROS) are excited or partially reduced forms of atmospheric oxygen, which are continuously produced during aerobic metabolism like many physiochemical processes operating throughout seed life. Previously, it was believed that ROS are merely cytotoxic molecules, however, now it has been established that they perform numerous beneficial functions in plants including many critical roles in seed physiology. ROS facilitate seed germination via cell wall loosening, endosperm weakening, signaling, and decreasing abscisic acid (ABA) levels. Most of the existing knowledge about ROS homeostasis and functions is based on the seeds of common plants or model ones. There is little information about the role of ROS in the germination process of halophyte seeds. There are several definitions for halophytic plants, however, we believed "halophytes are plants that can grow in very saline environment and complete their life cycle by adopting various phenological, morphological and physiological mechanisms at canopy, plant, organelle and molecular scales". Furthermore, mechanisms underlying ROS functions such as downstream targets, cross-talk with other molecules, and alternative routes are still obscure. The primary objective of this review is to decipher the mechanisms of ROS homeostasis in halophytes and dry seeds, as well as ROS flux in germinating seeds of halophytes.