High Salinity Levels Research Articles

Evaluation of Salicornia bigelovii Germplasm for Food Use in Egypt and the United Arab Emirates Based on Agronomic Traits and Nutritional Composition.

Climate change significantly aggravates the quality of soil and water, especially in desert regions such as the United Arab Emirates (UAE) and Egypt concluding in an alarming increase in salinity in the reservoirs of the natural resources. Saline farming rises as a promising solution, utilizing low-quality water and land resources to grow salt-tolerant varieties of conventional crops and halophytes. Samphire (Salicornia spp.) is among the most popular multi-purpose halophytes that are locally consumed in several countries around the world as a vegetable. Six Salicornia bigelovii genotypes (ICBA-2, ICBA-3, ICBA-4, ICBA-8, ICBA-9, ICBA-10) were evaluated for their agronomic performance and nutritional composition in Dubai in UAE and, for the first time, at the Red Sea Governorate in Egypt in the 2019–2020 season using saline groundwater for irrigation (ECw = 26 and 6.6 dS/m, respectively). ICBA-10 performed well in both locations with high green biomass and seed yield (10.9 kgm−2 and 116.3 gm−2, respectively, in UAE; 7.7 kgm−2 and 82.9 gm−2, respectively, in Egypt). ICBA-10 was, overall, also good in ion accumulation, total amino acids and unsaturated fatty acids content in both locations for shoots and seeds. Our results indicated that a lack of a drainage system and leaching fraction, the silt loam texture and the drip irrigation system might have contributed in the gradual accumulation of salts in the soil at Mubarak Valley at the end of the experiment at a higher level than ICBA. Apart from the agronomic parameters, higher salinity levels also affected ion accumulation, the amino acids and the fatty acids content for both shoots and seeds, whereas the proximate composition was affected to a lesser extent. Our findings on the high unsaturated fatty acids content under higher salinity corroborate the nutritional value of S. bigelovii oil. Due to its euhalophyte nature, S. bigelovii is a valuable source of minerals, amino acids and antioxidants that render it the most promising salt-loving plant for food use.

Improving the Tolerance to Salinity Stress in Lettuce Plants (Lactuca sativa L.) Using Exogenous Application of Salicylic Acid, Yeast, and Zeolite.

Salinity is among the most limiting factors of crop production worldwide. This study aims to investigate the influence of the exogenous application of zeolite, yeast, and salicylic acid in alleviating the negative effect of salt stress under field conditions. Lettuce plants (Lactuca sativa L. cv. Batavia) were tested in a split-plot arrangement replicated three times. The salt stress was applied as a whole-plot factor in the concentrations (0 mM, 50 mM, 100 mM, and 150 mM NaCl). After 28 days of sowing, the plants were sprayed twice during the foliage growth with (control, salicylic acid 0.02%, yeast extract 3%, and zeolite 0.5%) as a split-plot factor. The length of roots and shoots, the number and area of leaves, and the biomass accumulation (dry and fresh weights) were measured 50 days after sowing. The concentrations of total soluble sugars, proline, Chlorophylls a and b in leaves have also been quantified. Salt stress significantly reduced the growth and the total chlorophyll of the lettuce plants (p < 0.05) and increased their proline and sugar contents’. Zeolite application improved the growth of lettuce at 0 and 50 mM NaCl, but at the highest salinity level only the number of leaves was improved by 15%. At a mild salinity stress, the application of salicylic acid has significantly (p < 0.05) increased the root length, height of plant, chlorophyll, and proline contents. Regarding the high stress levels (100 and 150 mM NaCl), yeast application showed the best tolerance to salinity stress by improving significantly most of the growth parameters (p < 0.05) but with lower proline, sugar, and chlorophyll contents. In general, foliar spray of yeast extract may offer a good alternative source of nutrients through leaves, leading to a better tolerance of the high salt stress exerted on roots.

Salt-tolerant genotypes and halotolerant rhizobacteria: A potential synergistic alliance to endure high salinity conditions in wheat

The interaction of salt-resistant and salt-sensitive wheat varieties with halotolerant bacterial strains has not been well understood. In a greenhouse experiment, the effect of three halotolerant bacterial strains ( Bacillus safensis AL, Bacillus pumilus HR, and Zhihengliuella halotolerans SB) on yield and morphological and biochemical traits of two wheat varieties (Qods, a salinity sensitive variety, and Narin, a salinity resistant variety) under different salinity levels (0, 40, 80, and 160 mM NaCl) was investigated. The results showed that salinity had a negative effect on all morphological and biochemical traits of both varieties. At all salinity levels, especially at higher levels of salinity (80 and 160 mM NaCl), the effect of bacterial strains on the growth indices of Narin variety was better than Qods variety. At 160 mM NaCl level, bacterial strains caused an increase of 10–45% in seed, stem, and root dry weight, K + /Na + ratio, P and Ca content, chlorophyll a , crude protein, and seed amylose and amylopectin content of Narin variety compared to Qods variety. At 160 mM NaCl level, these bacteria also increased the 2,2-Diphenyl-1-picrylhydrazyl radical scavenging capacity by 21%, phenol content by 32%, and proline content by 6% in Narin variety compared to Qods variety. Higher grain yields were observed in the Narin variety inoculated with B. safensis AL and in the Qods variety inoculated with Z. halotolerans SB at all salinity levels. However, bacterial performance was variable, depending on salinity level and variety. The content of seed amylose and amylopectin in Qods variety was higher than Narin variety. In general, the Narin variety inoculated with bacterial strains in this study showed a better response to salinity stress than Qods variety. This can be a challenge for producing biofertilizers for varieties whose resistance to salinity is unknown. Overall, the results of this study emphasize on considering the best bacterial strain-wheat variety-salinity level combination to increase wheat yield. • Salt resistant variety inoculated with bacteria showed a better response to salinity than salt sensitive. • The content of seed amylose and amylopectin in salt sensitive variety was higher than salt resistant variety. • This study showed a challenge for producing biofertilizers for varieties whose resistance to salinity is unknown. • To increase wheat yield under salt stress, the best bacterium-wheat variety-salinity level combination should be selected.

Strengthening the Agroclimatology Analysis against Local Wisdom Paddy Planting Time at Coastal Area in Indonesia

Coastal paddy fields are areas that have distinctive land characteristics that affected local wisdom in the paddy cropping calendar. The local wisdom of the coastal paddy planting schedule is a cultural heritage that is aimed to accelerate the planting time, to minimize the risk, to adapt with the optimum planting time or to implement the local paddy varieties. This paper discusses the agro-climatology analysis to provide scientific strengthening to the local wisdom of the coastal paddy cropping calendar in Banyuasin, Kapuas, Tanah Laut, and Kutai Kertanegara Regency. The results of the analysis illustrate that the local wisdom of paddy planting time in Banyuasin is carried out before the beginning of the rainy season to avoid damage when salty water runoff occurs through rob at the critical paddy growth phase. The paddy planting time in Kapuas is done at the peak of the rainy season to avoid acidity poisoning during paddy growth. The paddy planting time in Tanah Laut is carried out before the start of the rainy season to provide the planting season duration with uses the long-lived local varieties. The paddy planting time in Kutai Kertanegara is done at the peak of the rainy season to avoid high salinity levels that have the potential to interfere with paddy growth and production. The information of the rainy season prediction and agro-climatology analysis provides an important role in determining the planting schedule according to local wisdom and rainfall condition in the four districts.

FLUORIDE AND CHILDREN’S HEALTH IN INDIA: DISTRICT LEVEL ANALYSIS

Quality issues in water such as presence of high levels of arsenic, nitrates, iron, salinity and fluoride has been witnessed in various parts in India. Presence of fluoride at alarming levels has led to severe threat to human survival. Prolong consumption of contaminated water with an unsafe fluoride level can lead to many diseases. Therefore, using the exogenous variation in fluoride across districts, we try to assess the impact of fluoride contaminated water on health outcomes particularly for children; dental and skeletal diseases. Usingnationally representative dataset for India, greater exposure to fluoride contamination is associated with adverse health outcomes amongst school going children. Our findings suggest that an additional increase in fluoride contamination leads to higher risk of dental (odds ratio-1.196) and skeletal diseases (odds ratio-1.206). Moreover, the intensity and incidence of such diseases (dental-1.398 and skeletal diseases-1.494) has increased drastically over time. Our estimates are also robust to district and time fixed effects. Our findings also suggestchildren who belong to the age group of 7-14 years of age experience such adverse health outcomes relatively more than those who belongs to 0-6 years of age, owing to visibility of fluoride related symptoms at later stages in life. Uniformity of our results holds even after using an alternative measure of estimation, Propensity Score Matching.

Potential of plant growth promoting bacterial consortium for improving the growth and yield of wheat under saline conditions.

Owing to inconsistent results of a single bacterial strain, co-inoculation of more than one strain under salinity stress could be a more effective strategy to induce salt tolerance. Co-inoculation of more than one bacterial strain could be more effective due to the presence of several growths promoting traits. This study was conducted to evaluate the effectiveness of multi-strains bacterial consortium to promote wheat growth under salinity stress. Several plant growth promoting rhizobacteria (PGPR) had been isolated and tested for their ability to grow in increasing concentrations of sodium chloride (NaCl). Those rhizobacterial strains having tolerance against salinity were screened to evaluate their ability to promote wheat growth in the presence of salinity by conducting jar trials under axenic conditions. The rhizobacteria with promising results were tested for their compatibility with each other before developing multi-strain inoculum of PGPR. The compatible PGPR strains were characterized, and multi-strain inoculum was then evaluated for promoting wheat growth under axenic conditions at different salinity levels, i.e., 2.1 (normal soil), 6, 12, and 18 dS m–1. The most promising combination was further evaluated by conducting a pot trial in the greenhouse. The results showed that compared to a single rhizobacterial strain, better growth-promoting effect was observed when rhizobacterial strains were co-inoculated. The multi-strain consortium of PGPR caused a significant positive impact on shoot length, root length, shoot fresh weight, and root fresh weight of wheat at the highest salinity level in the jar as well as in the pot trial. Results showed that the multi-strain consortium of PGPR caused significant positive effects on the biochemical traits of wheat by decreasing electrolyte leakage and increasing chlorophyll contents, relative water contents (RWC), and K/Na ratio. It can be concluded that a multi-strain consortium of PGPR (Ensifer adhaerens strain BK-30, Pseudomonas fluorescens strain SN5, and Bacillus megaterium strain SN15) could be more effective to combat the salinity stress owing to the presence of a variety of growth-promoting traits. However, further work is going on to evaluate the efficacy of multi-strain inoculum of PGPR under salt-affected field conditions.

Mitigation of Salinity Stress in Maize Seedlings by the Application of Vermicompost and Sorghum Water Extracts.

Abiotic stresses are important constraints limiting crop productivity worldwide. Salinity is one of the most devastating environmental factors restraining the production of crops. It is urgently needed to search for environmentally safe and sustainable approaches to mitigate the harmful effects of salinity on plants. Hence, applying vermicompost and low-dose aqueous extract of sorghum delivers a pragmatic solution to ameliorate the detrimental outcomes of salinity on maize seedlings (Zea mays L.). The experiment consisted of three factors, each at different levels, i.e., salinity (control, 6, and 12 dS m−1), vermicompost (control, 5, and 10%), and sorghum water extract (control, 1, and 2%). Higher salt stress negatively influenced the morpho-physiological traits of maize. Nonetheless, applying vermicompost and sorghum water extract at 10% and 2%, respectively, increased tolerance against salinity. The application of 2% sorghum water extract and 10% vermicompost significantly improved morphological characteristics, chlorophyll contents, activities of antioxidant enzymes, leaf and root K+/Na+ ratio, and K+ contents. It decreased Na+ concentration, H2O2, and malondialdehyde contents at higher salinity levels. It can be concluded that soil-applied vermicompost and foliar-applied sorghum water extract mitigates the adverse impacts of salinity by activating the antioxidant defense system, improving chlorophyll contents, and reducing the accumulation of Na+ under salinity.

A GBS-based genome-wide association study reveals the genetic basis of salinity tolerance at the seedling stage in bread wheat (Triticum aestivum L.).

High salinity levels affect 20% of the cultivated area and 9%–34% of the irrigated agricultural land worldwide, ultimately leading to yield losses of crops. The current study evaluated seven salt tolerance-related traits at the seedling stage in a set of 138 pre-breeding lines (PBLs) and identified 63 highly significant marker-trait associations (MTAs) linked to salt tolerance. Different candidate genes were identified in in silico analysis, many of which were involved in various stress conditions in plants, including glycine-rich cell wall structural protein 1-like, metacaspase-1, glyceraldehyde-3-phosphate dehydrogenase GAPA1, and plastidial GAPA1. Some of these genes coded for structural protein and participated in cell wall structure, some were linked to programmed cell death, and others were reported to show abiotic stress response roles in wheat and other plants. In addition, using the Multi-Trait Genotype-Ideotype Distance Index (MGIDI) protocol, the best-performing lines under salt stress were identified. The SNPs identified in this study and the genotypes with favorable alleles provide an excellent source to impart salt tolerance in wheat.

The effects of hydrological connectivity blocking on Suaeda salsa development in the Yellow River Delta, China

Blocking of hydrological connectivity could greatly impact the sediment deposition process and change water and salinity conditions, which in turn affect plant germination, growth, and development in delta wetlands. A 2-year experiment, which included the effects of soil burial, water, and salinity on germination, growth, and production, was conducted to examine the function of hydrological connectivity blocking on the development of Suaeda salsa, a halophyte species. The results demonstrated that soil burial, water, and salinity all had significant effects on seed germination, plant growth, and production (p &amp;lt; 0.05). Seed germination decreased as soil buried depth increased (&amp;lt; 4 cm), and seeds did not germinate successfully when the buried depth was &amp;gt; 4 cm. Seed germination was the highest at 0 cm burial. However, moderate burial was beneficial for seedling emergence; therefore, the survival rate was the lowest when seeds were distributed at the surface (0 cm). Water and salinity both significantly affected the germination, growth, and productivity of S. salsa. Moderate salinity (10–20 g/kg) and fluctuating water (0–10 cm water depth) were suitable for seed germination and plant growth. Low salinity (&amp;lt; 10 g/kg), High salinity (&amp;gt;20 g/kg), drought, and high water levels (long-term flooding with water depth &amp;gt; 10 cm) were not conducive to the growth of S. salsa, and biomass and seed yield were also reduced. As a halophyte, salinity that is too low or too high is unsuitable for S. salsa population. Water and salinity also significantly affected S. salsa population (p &amp;lt; 0.05). In particular, water can offset the hazards of high salt concentrations. Blocking of hydrological connectivity can influence seed germination, yield, and vitality. In this case, S. salsa may have died out from the coastal wetland due to the lack of hydrological connectivity restoration.

Overexpression of eelgrass Rare Cold Inducible 2 (RCI2) maintains chlorophyll content in Arabidopsis subjected to high salinity and dehydration

Eelgrass (Zostera marina) is a monocotyledonous plant found in seawater (seagrass). Eelgrass has many physiological characteristics that enable it to cope with salinity, hyperosmolarity, and hypoxia, as well as to live in marine environments. Germinating seedlings are sensitive to high levels of salinity, which inhibit germination and seedling growth. Thus, potent mechanisms likely protect eelgrass seedlings during early development. In this study, to identify the eelgrass genes required for abiotic-stress tolerance, 57 genes that are highly expressed during seed germination were isolated from a cDNA library derived through seed germination. We focused on ZoRCI2B, which encodes the small-membrane protein RCI2 thought to be involved in various stress tolerance responses. ZoRCI2B expression was high during seed germination and low in mature plants. Expression was upregulated under high water temperature and high salinity, and by dehydration and low dissolved-oxygen concentrations in leaves. The results of this study imply that ZoRCI2B may participate in adaptation to various abiotic stresses. Growth inhibition was reduced and chlorophyll content was maintained at higher levels in ZoRCI2B-overexpressing Arabidopsis exposed to salinity or dehydration. However, various temperature and flooding culture conditions led to no differences in the growth of overexpressing or wild-type plants. These results indicate that ZoRCI2B maintains chlorophyll content under salinity and dehydration stress, and could be applied to impart stress tolerance to various plants.

Physiological metabolic topology analysis of Halomonas elongata DSM 2581T in response to sodium chloride stress.

The halophilic bacterium Halomonas elongata DSM 2581T generally adapts well to high level of salinity by biosynthesizing ectoine, which functions as an important compatible solute protecting the cell against external salinity environment. Halophilic bacteria have specific metabolic activities under high-salt conditions and are gradually applied in various industries. The present study focuses on investigating the physiological and metabolic mechanism of H. elongata DSM 2581T driven by the external salinity environment. The physiological metabolic dynamics under salt stress were investigated to evaluate the effect of NaCl stress on the metabolism of H. elongata. The obtained results demonstrated that ectoine biosynthesis transited from a nongrowth-related process to a growth-related process when the NaCl concentration varied from 1% to 13% (w/v). The maximum biomass (Xm = 41.37 g/L), and highest ectoine production (Pm = 12.91 g/L) were achieved under 8% NaCl. Moreover, the maximum biomass (Xm ) and the maximum specific growth rates (μm ) showed a first rising and then declining trend with the increased NaCl stress. Furthermore, the transcriptome analysis of H. elongata under different NaCl concentrations demonstrated that both 8% and 13% NaCl conditions resulted in increased expressions of genes involved in the pentose phosphate pathway, Entner-Doudoroffpathway, flagellar assembly pathway, and ectoine metabolism, but negatively affected the tricarboxylic acidcycle and fatty acid metabolism. At last, the proposed possible adaptation mechanism under the optimum NaCl concentration in H. elongata was described.

Morphogenetic Response of Assorted Rice Genotypes to Salinity in Tanzania

Salinity, where salts concentrate on the soil surface causing severe decline of crop yields, is a worldwide problem. In Tanzania salinity is one of the major soil degradation challenges affecting over 3.5 million hectares limiting agriculture productivity of various crops including rice. Most of the varieties grown are sensitive to salts and inadequate tolerant cultivars available in the country. A hydroponics mass screening technique using Yoshinda Solution was used to test the 102 genotypes in NaCl- saline treated and non-treated solution at Tanzania Agricultural Research Institute (TARI-Dakawa Centre). Different salt concentrations (4 dSm-1, 6 dSm-1, 8 dSm-1 and 10 dSm) were used and the experiment was done in three replications. The genotypic variability for salinity tolerance was observed as less salt injury symptoms, low Na+ accumulation and Na+/K+ ratio in plant tissues and high biomass accumulation (fresh weight and dry weight). Results revealed further those 28 genotypes (28.45%) out of 102 showed tolerance to salinity, at high salinity level of 10dSm-1. Lines namely SR35266-2-18-2-1, SR35250-1-19-1-1, SR23364-128-1762-1-HV-1-1, SR35230-1-12-1-1, SR23364-128-1986-1-HV-1-1, SR34590-HB3433-4-1-1, SR35266-2-7-1-1, PBR1000922-1 and SR34053 (#5-52)-1-4-2-10-3-3 showed high performance under high salt conditions. Others includes SR35266-3-1-5-1, SR34574-2-10-3-1-2-1, SR35278-2-10-1-1, SR35250-2-3-1-1, SR35266-3-2-3-1, SR35266-3-2-4-1, SR23364-133-184-1-HV-1-1, SR34592-HB-1-HV-1, and SR34042F3-22-1-1-5-3 indicated tolerance to salt and had high dry matter as well. All the genotypes had increased levels of Na+ and differential performance was observed in some genotypes under saline and non-saline conditions. Among these three lines namely SR35266-2-7-1-1, SR23364-128-1762-1-HV-1-1, and SR34590- HB3433-4-1-1expressed high dilution ability as the K+ and Na+ concentrations were lower compared to other genotypes. The study, therefore, suggests that the lines can be used in breeding programs to develop varieties with potential to salt tolerance and other traits.

Deeper insight into the effect of salinity on the relationship of enzymatic activity, microbial community and key metabolic pathway during the anaerobic digestion of high strength organic wastewater

The threshold salt concentration to inhibit the anaerobic digestion (AD) has been intensively investigated, but its insight mechanism is not fully revealed. Therefore, this study systematically investigated the effect of salinity on acidogenesis and methanogenesis and its mechanism. Results showed that low salinity level (i.e. 0.6%) had stimulatory effect on volatile fatty acids (VFA) and methane production, while significant inhibition was observed with further increased salinity. Moreover, high salinity limited the butyric acid degradation at acidogenesis process. The decreases of enzymes (AK and PTA) activity and functional genes (ackA, pta and ACOX) expression that related to β-oxidation explained the butyric acid accumulation at high salinity levels. Microbial community analysis revealed high salinity levels significantly inhibited the proliferation of Syntrophomonas sp., which are known to be associated with butyric acid degradation. Similarly, the relative abundance of acetoclastic methanogen (Methanothrix sp.) and methylotrophic methanogen (Methanolinea sp.) significantly decreased at salinity condition.

Halobacterium salinarum NRC-1 Sustains Voltage Production in a Dual-Chambered Closed Microbial Fuel Cell.

Sustained bioenergy production from organisms that thrive in high salinity, low oxygen, and low nutrition levels is useful in monitoring hypersaline polluted environments. Microbial fuel cell (MFC) studies utilizing single species halophiles under salt concentrations higher than 1 M and as a closed microbial system are limited. The current study aimed to establish baseline voltage, current, and power density from a dual-chambered MFC utilizing the halophile Halobacterium salinarum NRC-1. MFC performance was determined with two different electrode sizes (5 cm2 and 10 cm2), under oscillating and nonoscillating conditions, as well as in a stacked series. A closed dual-chamber MFC system of 100 mL capacity was devised with Halobacterium media (4.3 M salt concentration) as both anolyte and catholyte, with H. salinarum NRC-1 being the anodic organism. The MFC measured electrical output over 7, 14, 28, and 42 days. MFC output increased with 5 cm2 sized electrodes under nonoscillating (p < 0.0001) relative to oscillating conditions. However, under oscillating conditions, doubling the electrode size increased MFC output significantly (p = 0.01). The stacked series MFC, with an electrode size of 10 cm2, produced the highest power density (1.2672 mW/m2) over 14 days under oscillation. Our results highlight the potentiality of H. salinarum as a viable anodic organism to produce sustained voltage in a closed-MFC system.

Mineral nutrient analysis of three halophytic grasses under sodic and saline stress conditions

Present study was carried out to assess the effects of soil salinity/sodicity on mineral nutrient status of Urochondra setulosa, Leptochloa fusca and Sporobolus marginatus at ICAR- Central Soil Salinity Research Institute, Karnal, Haryana during 2016–19. Treatments of salinity/sodicity (pH ~ 9.5, pH ~ 10, ECe ~ 30 dS/m, ECe ~ 40 dS/m and ECe ~ 50 dS/m) were created in microplots (2.5 m × 1.5 m × 0.5 m) using saline/sodic water. Na+ and Cl– content (% DW) significantly increased with increasing sodicity/salinity stress condition in all three grass halophytes, whereas K+ content decreased. These grass halophytic species showed relatively less reduction in Ca, Mg and Fe contents up to sodic stress of pH ~ 9.5 and salinity level of ECe ~ 40 dS/m. Zn, Cu and Mn content decreased with increasing stress conditions but higher decrease was observed under sodic stress. The Na+/K+ and Na+/Ca2+ ratio was considered as indicators for measuring salt tolerance in plants. Na+/K+ ratio increased with increasing stress condition in all the three grasses but Leptachloa maintained their Na+/K+ near pH 1.0 under sodic stress condition and also maintained their Na+/Ca2+ below 1.0 up to pH ~ 9.5 and ECe ~ 40 dS/m. Higher sodic stress of pH~10.0 caused significant increase in Na+/Ca2+ in Urochondra and Sporobolus, whereas under highest salinity level, Leptachloa showed highest value for Na+/Ca2+. Changes in the accumulation patterns of nutrient in response to salinity is an important aspect and study showed highest positive correlation between Ca - Mg &amp; Zn and negative between Na - Ca and K.

Validating a smart nutrient solution replenishment strategy to save water and nutrients in hydroponic crops

Sustainable use of water and nutrients is fundamental in modern Mediterranean greenhouses and the use of modern decision support systems (DSS) can contribute to this direction. This work focuses on implementing new elements in water and nutrient recycling in cropping systems under saline conditions. Thus, two nutrient solution (NS) control strategies were applied to tomato crops grown in a recirculated NS under low- and high-salinity (NaCl) conditions. According to the first strategy, (i.e., Standard-STD) NS was replenished with water and nutrients based on predetermined “uptake concentrations” (UCs), i.e., nutrient to water uptake ratios, following standard commercial practices. According to the second strategy, NS was replenished by applying recalculated UCs of all nutrients after chemical analysis of a drainage solution sample using the software NUTRISENSE (NTS). Compared with the STD strategy, tomato plants treated with NTS retained drainage nutrient concentrations closer to the optimal values irrespectively of the salinity treatment. This eventually accounted for a smaller deviation from the mean threshold salinity value in the root zone at higher salinity levels, thus plants retained water consumption and crop yield potential at higher stomatal conductance minimizing physiological impacts of salinity on plants. Nutritional control strategies did not impose substantial difference in the UCs for most of the nutrients; however, this was not the case under salinity. Nutrient UCs determined and NTS strategy can be successfully used in DSS to optimize nutrient supply and prolong recirculation, thereby saving precious water and nutrients, in Mediterranean hydroponic crops with particular emphasis on saline environments.

Seeds priming with ß-aminobutyric acid alleviated salinity stress of chickpea at germination and early seedling growth

Salinity stress is one of the most prevalent environmental factors that severely affect seed germination, early growth stages, and crop production. The present study was carried out to evaluate the protective role of β-aminobutyric acid (BABA) in alleviating salt stress in chickpea (Cicer arietinum L.) varieties (Jabel Marra, Porgeg and Shendi) under four concentrations of NaCl solutions (0, 50, 100, and 150 mM NaCl). Three levels of β-aminobutyric acid (0, 0.25, and 0.50 mM) were applied. Germination and seedling attributes were measured. A high level of salinity (150 mM NaCl) increased mean germination time by 10.0% and decreased the coefficient velocity of germination and root dry weight by 12.1% and 96.2%, respectively, compared with the control. ‘Jabel Marra’ significantly surpassed other studied varieties in germination characters, while at seedling growth, ‘Shendi’ outperformed other varieties in root and shoot length, fresh, and dry weights. Seeds treated with 0.25 mM BABA caused increment on water uptake by 18.1% compared with 0.0 mM BABA. At 150 mM NaCl, seeds primed with 0.50 mM BABA increased the germination percentage of ‘Jabel Marra’ and ‘Porgeg’ by 6.3% and 11.9% as compared with 0.0 mM BABA. Under 50 mM NaCl and 0.50 mM BABA, root length, shoot length, shoot fresh weight, and root dry weight were increased by 170.6%, 44.8%, 80%, and 49.3%, respectively, relative to 0.0 mM BABA. The present study results suggested that seed priming by BABA could be useful to alleviate the salinity stress of chickpea at germination and early seedling growth.

Distribution of breeding waterbirds in relation to wetland characteristics in the Oued Righ valley in the Algerian Sahara

Abstract In the framework of this study 14 breeding species were identified in the wetland complex of the Oued Righ valley in the Algerian Sahara. Six species of breeding Anatidae were reported, two of which are classified as vulnerable and threatened, namely, the ferruginous duck Aythya nyroca and the marbled teal Marmaronetta angustirostris. For shorebirds, we noted reproduction of the pied avocet Recurvirostra avosetta, the black-winged stilt Himantopus Himantopus, and the Kentish plover Charadrius alexandrinus in most of the wetlands studied. We report for the first time nesting of the slender-billed gull Chroicocephalus genei at Chott Merouane with 72 pairs recorded during the breeding season 2018. This colony was associated with the larger colony of greater flamingo Phoenicopterus roseus composed of 640 pairs. Principal component analysis (PCA), gathering 69.74% of the information, showed a significant correlation between the distribution of different bird species and the main environmental factors, that is, vegetation, water surface area, water depth, and salinity, and a strong correlation between the species of Annatidae and Rallidae, which are associated with less-saline environments rich in vegetation and deep water, with the exception of shelducks, which prefer large surface areas with less-dense vegetation and more holomorphic water. For the shorebirds such as R. avosetta and H. himantopus, there was a clear preference for large wetlands with shallow water and relatively high salinity. A remarkable correlation was also noted for P. roseus, where a strong distribution of breeding populations was observed in areas with the highest salinity levels and a vast surface area.

Effect of moderate salinity on Golden Thistle (Scolymus hispanicus L.) grown in a soilless cropping system

• Soilless cultivation of S. hispanicus l. improved plant growth and yield characteristics. • S. hispanicus L. was resilient to moderate salinity until 90 days after transplant. • Salinity level of 10.0 and 15.0 mM improved functional quality characteristics. • Physiological indicators significantly declined at salinity levels of 10 and 15 mM NaCl. Selecting salt-tolerant crop species for cultivation might be a feasible option to maintain crop productivity in arable lands affected by salinity. In this context, here we examine the responses of the wild edible green golden thistle ( Scolymus hispanicus L.) to moderate levels of salinity when grown in a soilless system for culinary use. Treatments were obtained by establishing four NaCl concentrations (0.5, 5.0, 10.0, and 15.0 mM) in a standard nutrient solution, resulting in initial solution electrical conductivities (EC) of 2.2, 2.8, 3.2, and 3.8 dS m − 1 , respectively. By the end of the experiment, 120 days after transplanting (DAT) drainage EC reached 2.65, 3.33, 3.96, and 4.51 dS m − 1 , respectively. At the first harvest, 90 DAT, the increase of the NaCl concentration had no significant impact on the number of leaves per plant, leaf fresh and dry weight [g plant −1 ], and root dry weight [g plant −1 ]. At the second harvest (120 DAT), 15.0 mM NaCl significantly decreased root and leaf fresh and dry weight without affecting the number of leaves per plant compared to 0.5 and 5.0 mM NaCl, while 10 mM NaCl had no impact on any of these parameters. The concentrations of K + , Ca 2+ , Mg 2+ , and P in the leaves were not influenced by the tested salinity levels, while those of organic-N and NO 3 − -N were significantly reduced by 10 and 15 mM NaCl, 90 DAT. Furthermore, 10 and 15 mM NaCl significantly increased the Cl − and Na + concentrations in leaves, but not in the roots. In the root tissues, only the K concentration was reduced by salinity while P increased at the highest salinity level (15 mM NaCl). Based on these results, we conclude that S. hispanicus L. is resilient to moderate salinity levels and can be considered a promising candidate plant for introduction to soilless cropping systems.

The epidermal bladder cell-free mutant of the salt-tolerant quinoa challenges our understanding of halophyte crop salinity tolerance.

Halophytes tolerate high salinity levels that would kill conventional crops. Understanding salt tolerance mechanisms will provide clues for breeding salt-tolerant plants. Many halophytes, such as quinoa (Chenopodium quinoa), are covered by a layer of epidermal bladder cells (EBCs) that are thought to mediate salt tolerance by serving as salt dumps. We isolated an epidermal bladder cell-free (ebcf) quinoa mutant that completely lacked EBCs and was mutated in REBC and REBC-like1. This mutant showed no loss of salt stress tolerance. When wild-type quinoa plants were exposed to saline soil, EBCs accumulated potassium (K+ ) as the major cation, in quantities far exceeding those of sodium (Na+ ). Emerging leaves densely packed with EBCs had the lowest Na+ content, whereas old leaves with deflated EBCs served as Na+ sinks. When the leaves expanded, K+ was recycled from EBCs, resulting in turgor loss that led to a progressive deflation of EBCs. Our findings suggest that EBCs in young leaves serve as a K+ -powered hydrodynamic system that functions as a water sink for solute storage. Sodium ions accumulate within old leaves that subsequently wilt and are shed. This mechanism improves the survival of quinoa under high salinity conditions.