Hortensins, Type 1 Ribosome-Inactivating Proteins from Seeds of Red Mountain Spinach: Isolation, Characterization, and Their Effect on Glioblastoma Cells

Ribosome inactivating proteins (RIPs) are specific N-β-glycosylases that are well-characterized in plants. Their enzymatic action is to damage ribosomes, thereby blocking protein translation. Recently, several research groups have been working on the screening for these toxins in edible plants to facilitate the use of RIPs as biotechnological tools and biopesticides and to overcome public prejudice. Here, four novel monomeric (type 1) RIPs have been isolated from the seeds of Atriplex hortensis L. var. rubra, which is commonly known as edible red mountain spinach. These enzymes, named hortensins 1, 2, 4, and 5, are able to release the β-fragment and, like many other RIPs, adenines from salmon sperm DNA, thus, acting as polynucleotide:adenosine glycosidases. Structurally, hortensins have a different molecular weight and are purified with different yields (hortensin 1, ~29.5 kDa, 0.28 mg per 100 g; hortensin 2, ~29 kDa, 0.29 mg per 100 g; hortensin 4, ~28.5 kDa, 0.71 mg per 100 g; and hortensin 5, ~30 kDa, 0.65 mg per 100 g); only hortensins 2 and 4 are glycosylated. Furthermore, the major isoforms (hortensins 4 and 5) are cytotoxic toward human continuous glioblastoma U87MG cell line. In addition, the morphological change in U87MG cells in the presence of these toxins is indicative of cell death triggered by the apoptotic pathway, as revealed by nuclear DNA fragmentation (TUNEL assay).

Phytochemical characterization, in vivo and in vitro biological activities of Atriplex lindleyi Moq. subsp. inflata

ETHNOPHARMACOLOGICAL RELEVANCE

Atriplex lindleyi Moq. subsp. inflata from Algeria is known for its traditional use for therapeutic properties.

AIM OF THE STUDY

We analysed quantitatively and qualitatively the infusion and diethyl ether, n-butanol and ethereal extracts of A. lindleyi, as well as assessed their acute toxicity, anti-inflammatory, antinociceptive and antioxidant activities.

MATERIALS AND METHODS

The total phenolic and flavonoid contents were quantified. The anti-inflammatory effect was assessed using a carrageenan-induced paw oedema assay and the antinociceptive effect was evaluated using an acetic acid-induced writhing method. In addition, antioxidant activity was examined by three tests: DPPH, reducing power and phenanthroline assays.

RESULTS

The quantity of total phenols in the roots of A. lindleyi was larger than in the aerial parts, while the amounts of total flavonoids were larger in the aerial parts than in the roots. The HPLC profiles allowed us to identify 32 compounds belonging to the phenolic acid and flavonoid classes. Intraperitoneal administration of the infusions and phenolic extracts in mice did not cause any symptoms of toxicity or mortality. Results revealed that the aerial parts and roots of A. lindleyi had potential anti-inflammatory and antinociceptive activities and were higher than diclofenac and paracetamol, respectively. The diethyl ether extract (DEE) of aerial parts and roots showed the greatest antioxidant activity in comparison to the other tested extracts.

CONCLUSION

The phenolic composition attempted to be identified by HPLC confers this plant's pharmacological potential. The antioxidant potential may be due to active ingredients, including ascorbic acid, in the two studied parts of A. lindleyi, which is a bioactive molecule with strong antioxidant properties. Also, detecting salicylic acid, the active antinociceptive ingredient of aspirin, gallic and ferulic acids may justify this subspecies' antinociceptive and anti-inflammatory potentials.

Growth performance, nutrient utilization, rumen fermentation, blood biochemistry, and carcass traits of lambs fed Atriplex nummularia L. hay-based diet supplemented with yeast or bacterial direct- fed microbial

Direct fed microbial may enhance the utilization of halophyte forages leading to improved animal growth and productivity. This study was conducted to evaluate Atriplex hay-based diet supplemented with yeast (Saccharomyces cerevisiae; SC) or bacteria (Bacillus subtilis and Lactobacillus casei; BAC) on lamb growth performance, digestibility, rumen fermentation, and carcass characteristics. Fifteen Barki lambs (90 ± 7 days of age and 18.6 ± 0.41 kg SE body weight; BW) were randomly assigned to three treatments for 120 days as follows: Control (basal diet without supplementation), SC and BAC diets, the basal diet supplemented with SC or BAC at 2 g/head/day, respectively. All lambs had similar dry matter (DM) intake, while lambs fed SC or BAC dies had higher (P < 0.05) total gain and average daily gain than those fed the control diet. Supplementation of SC or BC increased (P < 0.05) the digestibility of DM, organic matter, and acid detergent fiber, tended to decrease (P < 0.05) the urine N excretion and enhanced the N balance compared to the control. Ruminal pH, acetate, total volatile fatty acids concentrations, and bacterial protein were increased (P < 0.05), while creatinine and urea concentrations were decreased (P < 0.05) by both additives. Compared to other diets, the BAC diet reduced (P < 0.05) triglycerides, total lipids, kidney fat, and eye muscle fat. In conclusion, both additives resulted in similar positive growth performance and feed utilization, while only the BAC additive had a beneficial advantage in reducing the fat content of the carcass.

Zinc accumulation in Atriplex lentiformis is driven by plant genes and the soil microbiome

Successful phytoremediation of acidic metal-contaminated mine tailings requires amendments to condition tailings properties prior to plant establishment. This conditioning process is complex and includes multiple changes in tailings bio-physico-chemical properties. The objective of this project is to identify relationships between tailings properties, the soil microbiome, and plant stress response genes during growth of Atriplex lentiformis in compost-amended (10 %, 15 %, 20 % w/w) mine tailings. Analyses include RNA-Seq for plant root gene expression, 16S rRNA amplicon sequencing for bacterial/archaeal communities, metal concentrations in both tailings and plant organs, and phenotypic measures of plant stress. Zn accumulation in A. lentiformis leaves varied with compost levels and was the highest in the intermediate treatment (15 %, TC15). Microbial analysis identified Alicyclobacillus, Hydrotalea, and Pseudolabrys taxa with the highest relative abundance in TC15, and these taxa were strongly associated with Zn accumulation. Furthermore, we identified 190 root genes with significant gene expression changes. These root genes were associated with different pathways including, abscisic acid and auxin signaling, defense responses, ion channels, metal ion binding, oxidative stress, transcription regulation, and transmembrane transport. However, root gene expression changes were not driven by the increasing levels of compost. For example, there were 15 genes that were up-regulated in TC15, whereas 106 genes were down-regulated in TC15. The variables analyzed explained 86 % of the variance in Zn accumulation in A. lentiformis leaves. Importantly, Zn accumulation was driven by Zn shoot concentrations, leaf stress symptoms, plant root genes, and microbial taxa. Therefore, our results suggest there are strong plant-microbiome associations that drive Zn accumulation in A. lentiformis and different plant gene pathways are involved in alleviating varying levels of metal stress. Future work is needed to gain a mechanistic understanding of these plant-microbiome interactions to optimize phytoremediation strategies as they will govern the success or failure of the revegetation process.

Screening of tolerance of Atriplex vulgatissima under zinc or lead experimental conditions. An integrative perspective by using the integrated biological response index (IBRv2)

The search for plants with a high capacity to tolerate and accumulate metals is an important issue in phytoremediation. In this sense, this study was conducted in the halophyte Atriplex vulgatissima to evaluate the effects of different concentrations of lead (Pb, 50 and 100 μM) or zinc (Zn, 100 and 200 μM) on morphological, physiological, and biochemical parameters as well as the accumulation patterns of this species. The results indicated that while essential metal Zn showed high translocation from roots to shoots (TF > 1), non-essential Pb was mainly accumulated in the roots (BCF>1). Regarding shape, both metals induced slenderness of the blade, but only Zn treatment reduced leaf size. No difference in biomass production and photosynthetic parameters was found between Pb and Zn treatments. Pb treatments did not show significant differences between treatments regarding water content (WC), pigment concentration, and the activity of superoxide dismutase (SOD) and guaiacol peroxidase (GPx), but did result in a decrease in catalase activity at 100 μM Pb. On the other hand, 200 μM Zn leads to a clear reduction in WC and pigment concentrations, along with an increase in SOD and GPx activities. In addition, ascorbate peroxidase (APx) activity showed a hormesis effect at 50 μM Pb and 100 μM Zn. Malondialdehyde increased with both Pb and Zn treatments. The integrated biological index (IBRv2) indicated that 200 μM Zn was the most affected treatment (IBRv2 = 19.02) and that under the same concentrations of metals (100 μM Pb or Zn), Pb treatments presented major stress (IBRv2 = 11.55). A. vulgatissima is a metallophyte with the potential for Pb phytostabilization and Zn phytoextraction, as well as a bioindicator of these metals. Its high biomass and deep roots, combined with its halophytic traits, make it suitable for bioremediation and monitoring programs.

Unveiling Alternative Oxidation Pathways and Antioxidant and Cardioprotective Potential of Amaranthin-Type Betacyanins from Spinach-like Atriplex hortensis var. 'Rubra'

A comprehensive oxidation mechanism was investigated for amaranthin-type betacyanins with a specific glucuronosylglucosyl moiety isolated from Atriplex hortensis 'rubra' using liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) and LC-Quadrupole-Orbitrap-MS (LC-Q-Orbitrap-MS). By employing one-dimensional (1D) and two-dimensional (2D) NMR, this study elucidates the chemical structures of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)-oxidized celosianins for the first time. These findings demonstrate alternative oxidation pathways for acylated betacyanins compared to well-known betanidin, betanin, and gomphrenin pigments. Contrary to previous research, we uncover the existence of 17-decarboxy-neo- and 2,17-bidecarboxy-xanneo-derivatives as the initial oxidation products without the expected 2-decarboxy-xan forms. These oxidized compounds demonstrated potent free radical scavenging properties. Celosianin (IC50 = 23 μg/mL) displayed slightly higher antioxidant activity compared to oxidized forms, 17-decarboxy-neocelosianin (IC50 = 34 μg/mL) and 2,17-bidecarboxy-xanneocelosianin (IC50 = 29 μg/mL). The oxidized compounds showed no cytotoxic effects on H9c2 rat cardiomyoblasts (0.1-100 μg/mL). Additionally, treatment of H9c2 cells with the oxidized compounds (0.1-10 μg/mL) elevated glutathione levels and exhibited protective effects against H2O2-induced cell death. These findings have significant implications for understanding the impact of oxidation processes on the structures and biological activities of acylated betalains, providing valuable insights for future studies of the bioavailability and biological mechanism of their action in vivo.

The nutritional composition of six plant species after irrigation with treated wastewater and possible hazards by heavy metal accumulation

A field experiment was conducted investigating the possibility of using treated wastewater (TWW) on sites affected by water scarcity in summer, waterlogging during the wet season, and salinity. A corresponding pot experiment was conducted comparable to the field experiment in Kalaât Landelous. The same plant species (Atriplex nummularia Lindl., Eucalyptus gomphocephala DC., Acacia cyanophylla Lindl., Casuarina glauca Sieber ex Spreng., Cupressus sempervirens L., and Pinus halepensis Mill.) were grown with the same treatments. While, in the field the plants, elemental composition cannot be linked to inputs by TWW, this was studied under controlled conditions. Additionally, a control was established lower in salinity receiving tap water. The effect of TWW irrigation on macro- and microelement uptake by the six plant species was studied. The treatments were high soil salinity under drained saline (DS) conditions, high salinity under waterlogged saline (WS), and a drained non-saline control (DNS: EC = 3.0 dS/m, pH = 8.4). TWW application under DS treatment increased Na, Cl, Ca, Mg, N, P, and K in most plant tissues compared to the control. TWW application in WS treatment resulted in an increase in heavy metals. Cu and Zn showed the highest bioaccumulation factor (BAF). The BAF in different plant tissues followed the order: Cu > Zn > Mn > Cd > Ni > Co > Pb. The plants accumulated significant amounts of metals in their roots.

Effect of jasmonic acid on the phytoremediation of dinitrophenol from wastewater by Solanum nigrum L. and Atriplex lentiformis (Torr.) S. Watson

Phytoremediation is one of the best methods for cleaning up natural resources like water because plants are eco-friendly and safe for the ecosystem. Hyperaccumulators, e.g., Solanum nigrum L. and Atriplex lentiformis (Torr.) S. Watson, have been used to remove toxic metals from soil and water through phytoremediation techniques, but it is unknown if they can remove hazardous chemicals such as dinitrophenol (DNP), from wastewater. A hydroponic experiment was conducted to study the efficiency of S. nigrum and A. lentiformis in removing DNP from wastewater. Jasmonic acid (JAC) was applied to the tested plants in two doses, 0.25 and 0.50 mmol, in an effort to better understand how it affects phytoremediation effectiveness. The growth of S. nigrum and A. lentiformis improved significantly (p < 0.05) by the foliar application of JAC. The applications of JAC1 and JAC2 significantly (p < 0.05) increased nutrient uptake and chlorophyll concentrations in S. nigrum and A. lentiformis plants. The foliar spraying of S. nigrum and A. lentiformis with JAC significantly (p < 0.05) increased the antioxidant enzymes activity, i.e., SOD and POD. The levels of osmoregulatory substances like proline and carbohydrates significantly (p < 0.05) increased after JAC was sprayed on S. nigrum and A. lentiformis plants. In the case of S. nigrum, the efficiency of DNP removal varied between 53 and 69%, with an average of 63%, while in the case of A. lentiformis, it varied between 47 and 62%, with an average of 56%. The removal efficiency of DNP reached 67 and 69% when S. nigrum was sprayed with JAC1 and JAC2. When JAC1 and JAC2 were sprayed on A. lentiformis, DNP removal efficiency rose from 47 to 60 and from 47 to 62%, respectively. S. nigrum and A. lentiformis plants can be grown normally and survive in dinitrophenol-contaminated water without showing any toxic symptoms. S. nigrum and A. lentiformis have a powerful antioxidant system and the ability to produce vital compounds that alleviate the stress caused by DNP toxicity. The findings are crucial for cleaning up polluted water and protecting the ecosystem's health from dangerous pollutants.

Phytoremediation of dinitrophenol from wastewater by atriplex lentiformis: effect of salicylic acid

Quail bush [Atriplex lentiformis (Torr.) S. Wats] plants were used in removing 2, 4-dinitrophenol (DNP) from wastewater in a hydroponic experiment. The hydroponic system contained three doses of DNP, i.e., 0, 10, and 20 mg L-1. Quail bush plants were sprayed with 0.1 mM salicylic acid (SA) to study its role in resisting DNP toxicity. DNP significantly (p < 0.05) reduced plant growth. Exposure of A. lentiformis plants to 20 mg L-1 of DNP reduced the total chlorophyl and relative water content by 39 and 24%, respectively. SA improved the antioxidant defense in terms of ascorbate peroxidase (APX) and polyphenol oxidase (PPO) activities. SA alleviated DNP toxicity by enhancing the production of osmoprotectants, e.g.,proline, phenols, and carbohydrates. SA enhanced the removal efficiency of DNP and the highest removal efficiency (96%) was recorded in the plants sprayed with SA and grown on 10 mg L-1 of DNP. A. lentiformis is a halophytic plant that has good physiological characteristics to resist 2, 4-dinitrophenol toxicity in wastewaters and is qualified to purify water from these harmful compounds. Exogenous application of 0.1 mM SA increased the defense system in A. lentiformis against 2, 4-dinitrophenol toxicity and enhanced the removal efficiency.

Phytostabilization of trace elements and 13C isotope composition of Atriplex atacamensis Phil. cultivated in mine tailings treated with organic amendments

Mining generates large quantities of mineral processing wastes that are typically stored in mine tailings (MT) ponds. Long-term exposure of the surrounding areas to the material from the tailings ponds has been reported to have adverse effects on both human health and the environment. The purpose of this study was to evaluate the ability of Atriplex atacamensis Phil. to phytostabilize metals (Cu, Fe, Mn, and Zn) and sulfur (S) when grown directly on mine tailings with and without compost (C) and humic substance (HS). The stress status of A. atacamensis Phil. was also evaluated through the ¹³C isotopic composition of bulk leaves. A 120-day greenhouse experiment was conducted and three treatments were evaluated: (i) MT without any amendments (control), (ii) MT + C (dose: 89 ton ha^-1), and (iii) MT + HS (0.72 ton ha^-1). Mine tailings material exhibited low salinity, alkaline pH, high extractable S-SO₄ concentrations, and low fertility; total Fe, Mn, and Zn concentrations were within the reference range for mine tailings, but total Cu concentrations were high at 1860 ± 236 mg kg^-1. The HS had higher pH, EC, CEC, and available concentrations of N, P, and K than compost, while S-SO₄ concentrations were similar in both amendments. ¹³C NMR analysis showed that the HS contained more alkyl, aromatic, and phenolic groups, while the compost was dominated by O-alkyl and carboxyl groups. At the end of the experiment, the MT + C treatment achieved a significant decrease in Cu, Fe, and Mn concentrations in the roots and aboveground parts of A. atacamensis Phil. and an increase in Zn values in both tissues. Both amendments increased the sulfur content in the aboveground parts, while metal concentrations under the HS treatment proved similar to control. Furthermore, the δ¹³CV-PDB values obtained in this study indicate that the organic amendments did not cause additional physiological stress to the plants compared to the MT treatment. Overall, A. atacamensis Phil. was shown to have the ability to phytostabilize metals and sulfur, making it a potential candidate species for in situ evaluation of the phytostabilization process on mine tailings.

Seasonal Assessment of some Potentially Toxic Elements with Possible Animal Health Risks in Atriplex canescens (Pursh) Nutt

In the present investigation Br (Bromine), Cr (Chromium) and Pb (Lead) concentrations were assessed employing X-ray florescence spectrometry to evaluate seasonal variation of these elements in the xero-halophyte Atriplex canescens (Pursh) Nutt., a shrub with high pastoral value. The results showed that A. canescens and its surrounding soil have similar accumulation patterns for Br and Pb across seasons, but Cr concentrations in shrubs are higher in spring than other seasons. The seasonal mean contents of trace elements in A. canescens descend in the following order: Cr (8.33 µg g^- 1) > Br (5.34 µg g^- 1) > Pb (0.24 µg g^- 1). The maximum element transfer factor (ETF) of Cr and Pb was recorded in summer and autumn. However, no significant difference between seasons was found for Br. Principle component analysis (PCA) showed that Br, Cr and Pb were associated negatively with soil during all seasons. In contrast, A. canescens was only associated to Cr contents in the spring. Results provide evidence also that the levels of Br, Cr and Pb were within the safety-limits recommended by the National Research Council (NRC) guidelines for animal nutrition.

Pseudomonas simiae augments the tolerance to alkaline bauxite residue in Atriplex canescens by modulating photosynthesis, antioxidant defense enzymes, and compatible osmolytes

In situ revegetation is effective in improving water-stable aggregation, preserving structural stability, and decreasing groundwater pollution to reduce the environmental risks posed by alkaline bauxite residue (ABR). Pseudomonas simiae, a plant growth-promoting rhizobacteria (PGPR), was used to promote Atriplex canescens growth challenged by ABR. The mechanism of P. simiae-induced plant growth promotion and tolerance against ABR stresses has been investigated. P. simiae was shown to alleviate ABR-induced stress in A. canescens by regulating photosynthesis and transpiration, inducing antioxidant defense, causing osmolyte accumulation, and altering plant morphology. Shoot dry weight, root dry weight, and root length of A. canescens were increased by 5.9%, 6.7%, and 11.5%, respectively, after inoculation with P. simiae for 60 days. Thus, it seems that P. simiae systemically regulated physiological processes in A. canescens favoring its growth under ABR treatments.

Atriplex canescens, a valuable plant in soil rehabilitation and forage production. A review

A. canescens (Pure) Nutt. is a halophytic forage shrub distributes in arid and semiarid regions, which has great use potential in disturbed lands for its strong adaptability and feeding value. At present, land degradation caused by salinization, desertification and heavy metal pollution is still expanding all over the world, meanwhile, stock raising in arid and semi-arid areas may face more shortage of forage supply. Although A. canescens is much accounted of in some regions, its application values are not widely concerned in some countries such as China. Therefore, a comprehensive understanding is needed to promote its application in these regions. In the review, we introduced the morphological and physiological characteristics of A. canescens, summarized its ecological and economic values, and we also discussed its use prospect and main problems in China. This review could be helpful for understanding of A. canescens adaptive characteristics and application values, thus promote its reasonable popularization and use in areas in need.

Characterization of cadmium accumulation and phytoextraction in three species of the genus Atriplex (canescens, halimus and nummularia) in the presence or absence of salt

This study aims to establish for the first time a comparison between the resistance to cadmium (Cd) stress of three halophyte species, Atriplex canescens, Atriplex halimus and Atriplex nummularia in addition to their already known tolerance for salt and drought. Plants were exposed to CdCl₂ (20 and 50 μM) in the presence or in the absence of salt (50 mM NaCl) for one and two months. The amount of accumulated Cd was determined in the roots and leaves as well as the amount excreted on the surface of the leaves. Physiological parameters such as chlorophyll content and stress biomarkers, including malondialdehyde and enzymatic activities, were then analyzed. The results show that these plants are able to neutralize the excess of reactive oxygen species resulting from treatments by activating the antioxidant defense mechanisms in order to restore the homeostasis of cells. All three species are also able to accumulate high amounts of Cd in the leaves (several hundred mg of Cd/kg of dry leaves) and this phenomenon is amplified in the presence of salt. All together our results allow to consider the three Atriplex species as hyperaccumulators in the presence/absence of salt and as good candidates in a strategy of Cd phytoextraction in the presence of low concentrations of the pollutant. Nevertheless, both A. canescens and A. nummularia species seem to have a higher capacity to hyper-accumulate Cd when the concentration of Cd reaches higher level of contamination.

Mineral composition of Atriplex halimus plant as influenced by genotype and thermal regime

Atriplex halimus grows in humid and saline warm regions of Mediterranean area showing high adaptability but less information is available on resistance to chilling temperatures.Potted plants of five clones (MAR1, GIO1, SAN3, PAL1, and FAN3) were cultivated during 30 months in four localities (Oristano, Tempio, Sassari, and Villasor). Every 6 months, leaves, stems and roots of plants were the object of mineral composition analysis (N, P, Na, K, Ca, Mg, Cu, Zn, Fe, and Mn). During the experiment, air temperature was recorded and hour degrees sums calculated for thresholds ranging from 0 °C to 35 °C.Leaves showed highest content of all elements, with the exception of iron.Plants showed ability to accumulate mineral elements in a synergic or antagonistic way. Accumulation of chilling hour degrees positively correlated with calcium in leaves and stems, and with manganese in the whole plant. Sodium in leaves, instead, was favored by high temperatures, which are unfavorable to nitrogen accumulation in roots. Magnesium accumulation in leaves and roots enhanced with moderately high temperatures. Two of the tested clones (GIO1 and SAN3) showed a relative low adaptability to the coldest conditions. The other three clones provided better performances with the best behavior of PAL1.

Evaluating the efficacy of Atriplex spp. in the phytoextraction of road salt (NaCl) from contaminated soil

Soil and freshwater salinization are growing issues worldwide. Road salt, primarily sodium chloride (NaCl), is a significant contributor to this issue in North America. In this study, the ability of three native Canadian halophytes (Atriplex patula, Atriplex hortensis, and Atriplex canescans) to remove Na⁺ and Cl^- from contaminated soil was investigated. Field and greenhouse studies determined plant survivability in roadside areas, as well as Na⁺ and Cl^- extraction levels. The Atriplex spp. accumulated 18-55 mg Na⁺ g^-1 dry weight (DW) and 41-64 mg Cl^- g^-1 DW when grown for a two-month period in soil spiked with NaCl to simulate a very highly contaminated roadside. Using A. patula, it would theoretically take 6 growing seasons to remove all salt from an area contaminated with 1540 μg Cl^- g^-1, while A. hortensis and A. canescens would take 19 and 9 years, respectively. Salt content in shoot components (seeds, stem, leaves) was determined to provide further insight on phytoextraction processes. In all three Atriplex species, the leaves had the highest Cl^- concentration, followed by the seeds (bracteoles included), with the lowest concentrations found in the stem. These novel findings provide important information for road salt remediation and indicate that using Atriplex spp. may be a viable way in which to reduce the environmental impact of road salting.

The impact of soil chloride concentration and salt type on the excretions of four recretohalophytes with different excretion mechanisms

Four natives Canadian recretohalophytic species: Atriplex canescens, Armeria maritima, Spartina pectinata, and Distichlis spicata were examined to determine their relative uptake and excretion of chloride in the context of phytoremediation. Adult plants were grown in soils contaminated with either sodium chloride or potassium chloride at various concentrations, then manually washed to collect the excreted salts. Atriplex canescens which has salt bladders, was found to have negligible excretions, suggesting that these structures release minimal amounts of salt onto the leaf's surface. Chloride excretions of S. pectinata and D. spicata increased with higher soil chloride concentrations. A. maritima showed minimal excretion until a threshold soil salinity was reached. This species shifted from a reliance on internal sequestration to secretion at higher soil salinity. The salt used in the media did not impact these trends, but D. spicata excreted significantly more chloride under sodium chloride conditions. While all four species studied were able to translocate significant amount of salt to their shoots, only S. pectinata, D. spicata, and A. maritima are suitable candidates for remediation by haloconduction. Among these, A. maritima showed the greatest potential and significantly reduced the soil chloride concentration by up to 60% in the highest concentration treatment (4 mg/g).HIGHLIGHTSArmeria maritima, Spartina pectinata, and Distichlis spicata are suitable species for remediation via haloconduction.Armeria maritima had the highest total extraction capacity at high soil chloride.Spartina pectinata had the most consistent excretion capacity and is the most suitable for remediation of soils with lower soil chloride.

Short-term leachability of salts from Atriplex-derived biochars

Disposal of concentrate from brackish water desalination is limited by concerns of salt leaching into fresh water sources. Prevention of salt from leaching can greatly increase desalination concentrate management costs, as there are few options to recover those costs. An option for concentrate disposal is to grow halophyte crops using the concentrate as irrigation water. The purpose of this study was to determine how much of the Ca, Mg, Na, and K taken up by Atriplex species during growth can be stabilized by pyrolysis, thus preventing those cations from returning into the soil solution after harvest. Results show that salts in the biomass are concentrated into the biochars and that pyrolysis conditions affect the amount of salt that can be leached with water. Ca was the most retained of the cations: 100% and 94% were retained in A. canescens biochars and A. lentiformis 600 °C biochar, respectively. Mg retention was similar: 100% and 93% retained for A. canescens and A. lentiformis 600 °C biochars, respectively. Increasing pyrolysis temperature increased the retention of Ca and Mg; trends for K and Na were inconsistent. Soil application of these biochars will still be problematic due to low retention of Na against short-term leaching, thus limiting the potential for on-site sequestration to enable land utilization for crop production. With more understanding of the salt formation and retention mechanisms within biomass, higher amounts of salt might be sequestered longer, while taking advantage of the carbon sequestration and soil quality benefits of biochars.

Do applications of soil conditioner mixtures improve the salt extraction ability of Atriplex nummularia at early growth stage?

The reclamation of salt-affected soils is considered a slow process that urges the development of faster recovery strategies as a priority. The present article aimed at investigating the effect of mixing different chemical and organic conditioners on the growth of Atriplex and its salt extraction efficiency during its early growth stage. A pot experiment was conducted on saline-sodic Cambisol cultivated with Atriplex for 60 days and subjected to the following conditioner mixtures: Atriplex; Atriplex + gypsum + organic matter; Atriplex + elemental sulfur + organic matter; and Atriplex + gypsum + elemental sulfur + organic matter. The mixtures of conditioners did not affect the Atriplex growth, but caused significant increase in Na⁺ and Cl^- contents in the dry matter of Atriplex plants. Additionally, there was an increase in the Atriplex's ability of extracting salt due to the application of the mixtures. Results suggest that the "gypsum + organic matter" mixture is preferable for a faster recovery of salts/sodium affected soils through phytoremediation by Atriplex plants, mainly due to a more significant increase in the efficiency of salt absorption.

Assessing the feasibility of using a closed landfill for agricultural graze land

Once landfills are closed and maintained according to the US Environmental Protection Agency's standards and regulations, they are potential sites for revitalization efforts, particularly via agricultural activities. This project was commissioned by the City of Tucson Environmental Services Department as part of an effort to explore ways to reuse one or more of the 16 landfills the department manages in the Tucson metropolitan area. The objective of this project was to assess the feasibility of using a closed landfill to support safe goat browsing. A site history and investigation was conducted at the Harrison Landfill in Tucson, Arizona, to characterize the soil quality and uptake of deleterious metals by the following plants observed at the landfill: Pennisetum ciliare (buffel grass), Baccharis sarothroides (desert broom), Salsola tragus L. (Russian thistle), Larrea tridentata (creosote), Tamarix ramosissima (salt cedar), and Atriplex canescens (fourwing saltbush). Site characterization data were combined with known goat browsing and plant consumption patterns to determine exposure risks. It was observed that soil concentrations of metals (Al, Ag, As, Be, Ba, Fe, Co, Cu, Cr, Cd, Fe, Mn, Ni, V, Se, Mo, Sn, Sb, Pb) did not exceed Arizona Department of Environmental Quality's soil remediation levels. Tamarix ramosissima, Baccharis salicifolia (willow baccharis), Pennisetum ciliare, Salsola tragus L., Baccharis sarothroides, Larrea tridentata, and Atriplex canescens contained metal concentrations that fell well within maximum tolerable levels. In general, this project determined that after soil and plant assessment, urban, arid landfills may be used effectively for economic development through agricultural grazing ventures.

Phytoextraction of salts by Atriplex Nummularia Lindl. irrigated with reject brine under varying water availability

Reverse osmosis is a widely known technology used to produce fresh water from brackish waters. However, the reject brine from desalination plants poses a serious threat to the environment due to soil and groundwater salinization. The aim of this study was to investigate the potential of Atriplex nummularia to extract salts from a soil irrigated with reverse osmosis brine, at varying moisture levels. A field experiment was conducted in a split-plot design, with randomized complete blocks replicated four times. Treatments consisted of irrigation with reject brine in the main plots, with four relative percentages of the soil moisture at field capacity (100, 85, 70, and 50%), and two levels of organic fertilization in the subplots (0 and 1.5 L plant^-1 of goat manure). The mineral composition of leaves and stems indicated that the highest salt extraction by plants occurred when soil moisture was maintained at 100% field capacity. The salt extraction capacity of A. nummularia indicates a high potential for phytoremediation of soils affected by brine disposal from reverse osmosis plants.

Assessing the Role of Differential Herbivore Performance Among Plant Species in Associational Effects Involving the Invasive Stink Bug Bagrada hilaris (Hemiptera: Pentatomidae)

Co-occurring plant species can influence the extent of damage to each other by altering the activity or abundance of a shared herbivore. One mechanism by which neighboring host plants exacerbate damage to a focal host is if the neighbor amplifies herbivore populations. We studied the performance of a shared herbivore on a native and an invasive plant, to estimate how strongly the presence of the invasive plant increases local herbivore abundance-in a system in which highly asymmetric spillover herbivory may occur. Specifically, we conducted a series of greenhouse experiments that measured reproduction, development, and survival of the invasive stink bug Bagrada hilaris Burmeister on an invasive annual forb, Sahara mustard (Brassica tournefortii), or a native perennial shrub, four-winged saltbush (Atriplex canescens). All measured aspects of stink bug performance revealed consistently greater performance on Br. tournefortii. Indeed, A. canescens appears to be insufficient for Ba. hilaris to complete its development. Nonetheless, preliminary damage assessments found that both plant species were used as feeding hosts, putative feeding lesions were a more reliable indicator of herbivory than was the degree of yellowing, and higher Ba. hilaris abundance was generally associated with greater sublethal damage to A. canescens. Thus, A. canescens appears to be susceptible to Ba. hilaris herbivory, though more research is needed to assess fitness impacts of this novel herbivore. Our results indicate that differential herbivore performance among host plants may be an important contributor to observed patterns of abundance of a shared herbivore and spillover herbivory between plants.

Water potential in soil and Atriplex nummularia (phytoremediator halophyte) under drought and salt stresses

Atriplex nummularia is a halophyte widely employed to recover saline soils and was used as a model to evaluate the water potentials in the soil-plant system under drought and salt stresses. Potted plants grown under 70 and 37% of field capacity irrigated with solutions of NaCl and of a mixture of NaCl, KCl, MgCl₂ and CaCl₂ reproducing six electrical conductivity (EC): 0, 5, 10, 20, 30, and 40 dS m^-1. After 100 days, total water (Ψ_{w, plant}) and osmotic (Ψ_{o, plant}) potentials at predawn and midday and Ψ_{o, soil}, matric potential (Ψ_{m, soil}) and Ψ_{w, soil} were determined. The type of ion in the irrigation water did not influence the soil potential, but was altered by EC. The soil Ψ_o component was the largest contributor to Ψ_{w, soil}. Atriplex is surviving ECs close to 40 dS m^-1 due to the decrease in the Ψ_w. The plants reached a Ψ_w of approximately -8 MPa. The water potentials determined for different moisture levels, EC levels and salt types showed huge importance for the management of this species in semiarid regions and can be used to recover salt affected soils.

Decision-making criteria for plant-species selection for phytostabilization: Issues of biodiversity and functionality

In polluted protected areas, using phytoremediation raises the question of the choice of the plant species to select. As an example, Atriplex halimus has been identified as a proliferative plant species that needs to be eradicated in the Calanques National Park (PNCal). Since it has been proven that the spontaneous populations of this plant species could phytostabilize shore waste deposits generated by past industrial activities within the PNCal territory, its status seems controversial, presenting a dilemma between biodiversity management of a protected area and ecological solutions for pollution management. To address this issue, we assessed the ability of A. halimus to grow on different soils from this territory, in order to estimate the potential invasiveness of this plant in this territory. Petri dish germinations and pot-growth experiments showed 50% germination of seeds collected on local individuals from the most polluted PNCal soil and 20% growth reduction of seedlings. Soil analysis showed that limitation of growth was caused by high pH value and sparsely available micronutrients as well as metal and metalloid contamination. Our results suggested that local populations of A. halimus may stabilize the highly metal and metalloid polluted salt-affected soils of the PNCal, with low seed germination potential lowering the eventuality of a propagation over the PNCal territory. As a consequence of this study, the administration of the PNCal decided not to remove A. halimus populations along the polluted coastline until another solution to prevent pollution dispersal had been found. This laboratory approach may be extended to other similar situations where plant species may be evaluated not only in term of phytoremediation potential but also in term of biodiversity preservation.

Effects of native grass cover crops on beneficial and pest invertebrates in Australian vineyards

Indigenous cover crops have the potential to promote an increase in natural enemies providing fortuitous control of pest species and other ecosystem services. We test this idea in a vineyard in south eastern Australia, where reduced water availability because of drought coupled with increased temperatures has generated interest in sustainable alternatives to the exotic perennial cover crops commonly planted. Three endemic perennial cover crops, comprising the grasses Austrodanthonia richardsonii and Chloris truncata and a mix of two saltbushes (Atriplex semibaccata and Atriplex suberecta) were established as cover crops and compared with introduced oats (Avena sativa). Abundance of a range of predators and parasitoids was higher in vines with native cover crops compared with the oat control. In addition, predation levels of sentinel eggs of a common vineyard pest, light brown apple moth (Epiphyas postvittana), were increased in the native cover crops. However, the native cover crops also increased the abundance of some potential pest species. Native plants therefore have potential to increase abundance of beneficial invertebrates that assist in pest control, but need to be used carefully to ensure that they do not increase local pest problems.

Impact of feeding saltbush twigs on feed intake, weight gain, and some mineral levels of fattening awassi lambs

This experiment was conducted to investigate the effect of the inclusion of saltbush (Atriplex sp.) on the productive performance and blood mineral profile of fattening lambs. Eighteen Awassi lambs, 70 +/- 3 days of age and 23 +/- 1.8 kg body weights, were randomly selected and divided into three equal groups. Lambs in group one (control) were offered 0.2 kg/day shredded straw of barley (tibin) as the sole source of roughage, while lambs in treatment groups 2 and 3 were provided either 0.2 kg/day Atriplex nummularia or Atriplex halimus as their sole roughage content for 10 weeks. All lambs were also provided 1.1 kg/day of concentrate ration. Although lambs fed A. halimus had significantly (P < 0.05) lower dry matter intake than the control group, the daily weight gain of the two groups of lambs were not significantly different (P > 0.05). Lambs fed either A. nummularia or A. halimus had significantly lower (P < 0.05) calcium and copper levels but significantly higher (P < 0.05) cobalt levels in their blood serum than the control group. Zinc blood serum level was not affected (P > 0.05) by the treatment diets. These results suggested that A. nummularia and A. halimus can substitute for barley straw in the ration of fattening Awassi lambs without compromising lambs weight gain; however, special attention should be given to the mineral status in lambs if saltbush is a major feed component for prolonged periods of time.

An in vitro evaluation of some unconventional ruminant feeds in terms of the organic matter digestibility, energy and microbial biomass

In vitro organic matter apparent digestibility (IVOMAD), true digestibility (IVOMTD), metabolizable energy (ME), net energy lactation (NEL), microbial nitrogen (MN) and synthesis of microbial biomass (MBM) were estimated to predict the nutritive values of some agricultural by-products, drought-tolerant range plants and browses. The relationships between in vitro gas production (GP), and true or apparent digestibility. MN and MBM were studied utilizing an in vitro incubation technique. The values of IVOMAD, IVOMTD, ME, NEL, GP, MBM and MN varied with the studied experimental materials. The true fermentation of the outside part of Atriplex leucoclada produced a higher volume of gas than the middle or the inside parts, and this was associated with an increase in the values of IVOMAD, IVOMTD, ME and NEL. However, screening off the wood from olive cake to obtain olive cake pulp increased the IVOMAD, IVOMTD, ME, NEL and the volume of gas production from the true fermented material. One ml of gas was generated from the true degradation of 5 mg of wheat straw, Moringa oleifera, Alhagi camelorum, Eucaliptus camaldulensis and A. leucoclada, from 11 mg of Prosopsis stephaniana and olive cake pulp, and from 20 mg of olive cake or olive cake wood. The amount of MN or MBM produced from 100 mg of truly fermented organic matter depended on the kind of the fermented material and amounted to 0.7-2.9 mg or 8-34 mg, respectively. Crude fibre was negatively correlated to IVOMAD, IVOMTD, ME and NEL. Gas production was positively correlated to IVOMAD and IVOMTD but negatively correlated to MBM and MN.