Salinity stress is one of the more prevailing abiotic stresses which results in significant losses in agricultural crop production, particularly in arid and semi-arid areas ....
Soil salinity has become a highly disastrous phenomenon responsible for crop failure worldwide, especially in countries with low farmer incomes and food insecurity. Soil salinity is often due to ...water accumulation in fields caused by improper flood irrigation whereby plants take up the water leaving salts behind. It is, however, the subsurface soil salinity that affects plant growth. This soil salinity prevents further water intake. There have been very few studies conducted for subsurface soil salinity estimation. Therefore our study aimed to estimate subsurface soil salinity (at 60 cm depth) for the early stage of wheat crop growth in a simplified manner using freely available satellite data, which is a novel feature and prime objective in this study. The study utilises SENTINEL‐1 SAR (synthetic aperture RADAR) data for backscatter coefficient generation, SENTINEL‐2A multispectral data for NDSI (normalised differential salinity index) generation and on‐ground equipment for direct collection of soil electrical conductivity (EC). The data were collected for two dates in November and December 2019 and one date in January 2020 during the early stage of wheat crop growth. The dates were selected keeping in mind the satellite pass over the study area of Rupnagar on the same day. Ordinary least squares regression was used for modelling which gave R2‐statistics of 0.99 and 0.958 in the training and testing phase and root mean square error (RMSE) of 1.92 and mean absolute error (MAE) of 0.78 in modelling for soil salinity estimation.
Key Message
A major QTL (qS7.1) for salinity damage score and Na+ exclusion was identified on chromosome 7H from a barley population derived from a cross between a cultivated variety and a wild ...accession. qS7.1 was fine-mapped to a 2.46 Mb physical interval and HvNCX encoding a sodium/calcium exchanger is most likely the candidate gene.
Soil salinity is one of the major abiotic stresses affecting crop yield. Developing salinity-tolerant varieties is critical for minimizing economic penalties caused by salinity and providing solutions for global food security. Many genes/QTL for salt tolerance have been reported in barley, but only a few of them have been cloned. In this study, a total of 163 doubled haploid lines from a cross between a cultivated barley variety Franklin and a wild barley accession TAM407227 were used to map QTL for salinity tolerance. Four significant QTL were identified for salinity damage scores. One (
qS2.1
) was located on 2H, determining 7.5% of the phenotypic variation. Two (
qS5.1
and
qS5.2
) were located on 5H, determining 5.3–11.7% of the phenotypic variation. The most significant QTL was found on 7H, explaining 27.8% of the phenotypic variation. Two QTL for Na
+
content in leaves under salinity stress were detected on chromosomes 1H (
qNa1.1
) and 7H(
qNa7.1
).
qS7.1
was fine-mapped to a 2.46 Mb physical interval using F
4
recombinant inbred lines. This region contains 23 high-confidence genes, with
HvNCX
which encodes a sodium/calcium exchanger being most likely the candidate gene.
HvNCX
was highly induced by salinity stress and showed a greater expression level in the sensitive parent. Multiple nucleotide substitutions and deletions/insertions in the promoter sequence of
HvNCX
were found between the two parents. cDNA sequencing of the
HvNCX
revealed that the difference between the two parents is conferred by a single Ala77/Pro77 amino acid substitution, which is located on the transmembrane domain. These findings open new prospects for improving salinity tolerance in barley by targeting a previously unexplored trait.
Nutrient resorption efficiency is an important nutrient conservation and ecophysiological mechanism of mangroves growing in saline environments. This study investigated the nitrogen, phosphorus, and ...potassium resorption efficiency of
Avicennia officinalis
L. growing across a salinity gradient with seasonal variations in the Sundarbans of Bangladesh. Due to decreasing salinity during the monsoon and postmonsoon seasons, the nutrient availability in soil and nutrient resorption efficiency did not vary significantly among the low-salinity, medium-salinity, and high-salinity zones. However, the nutrient availability in the medium-salinity and high-salinity zones was significantly lower than that in the low-salinity zone during the premonsoon season due to increased salinity. Consequently, nutrient resorption efficiency in the medium-salinity and high-salinity zones was significantly higher than that in the low-salinity zone during the premonsoon. Further, leaf vein density of
A. officinalis
in the medium-salinity and high-salinity zones was significantly higher than that in the low-salinity zone. This modification in vein density was the mechanism for the higher nutrient resorption efficiency of
A. officinalis
in the medium-salinity and high-salinity zones than that in the low-salinity zone. This plasticity in nutrient resorption efficiency is a physiologically adaptive mechanism that enables
A. officinalis
to persist in increasingly saline environments due to climate change.
Sodium nitroprusside (SNP) and hydrogen peroxide (H2O2), as priming agents, have the well‐recorded property to increase plant tolerance against a range of different abiotic stresses such as salinity. ...In this regard, the present study was conducted to evaluate the effect of different levels of SNP (100 and 200 µM) and H2O2 (2.5 and 5 mM) as well as their combinations under salt stress (0 and 50 mM NaCl) on key physiological and biochemical attributes of the economically important aromatic plant basil (Ocimum basilicum L.) grown under hydroponic culture. Results revealed that morphological parameters such as plant height, root length, leaf fresh and dry weights (FW and DW) were significantly decreased by salinity stress, while SNP and H2O2 treatments, alone or combined, increased FW and DW thus enhancing plant tolerance to salt stress. Furthermore, 200 µM SNP + 2.5 mM H2O2 appeared to be the most effective treatment by causing significant increase in chlorophyll a and b, anthocyanin content and guaiacol peroxidase and ascorbate peroxidase enzymes activities under saline condition. In addition, analytical measurements showed that essential oil profile (concentration of main components) under salt stress was mostly affected by SNP and H2O2 treatments. The highest increase was observed for methyl chavicol (43.09–69.91%), linalool (4.8–17.9%), cadinol (1.5–3.2%) and epi‐α‐cadinol (0.18–10.75%) compounds. In conclusion, current findings demonstrated a positive crosstalk between SNP and H2O2 toward improved basil plant tolerance to salt stress, linked with regulation of essential oil composition.
Today, salinity stress is one of the most important abiotic stresses in the world, because it causes damage to many agricultural products and reduces their yields. Oxidative stress causes tissue ...damages in plants, which occurs with the production of reactive oxygen species (ROS) when plants are exposed to environmental stresses such as salinity. Today, it is recommended to use compounds that increase the resistance of plants to environmental stresses and improve plant metabolic activities. Salicylic acid (SA), as an intracellular and extracellular regulator of the plant response, is known as one of these effective compounds. Damask rose (Rosa damascena Mill.) is a medicinal plant from the Rosaceae, and its essential oils and aromatic compounds are used widely in the cosmetic and food industries in the world. Therefore, considering the importance of this plant from both medicinal and ornamental aspects, for the first time, we investigated one of the native cultivars of Iran (Kashan). Since one of the most important problems in Damask rose cultivation is the occurrence of salinity stress, for the first time, we investigated the interaction of several levels of NaCl salinity (0, 4, 8, and 12 ds m.sup.- 1) with SA (0, 0.5, 1, and 2 mM) as a stress reducer. Since salinity stress reduces plant growth and yield, in this experiment, the results showed that the increase in NaCl concentration caused a gradual decrease in photosynthetic and morphological parameters and an increase in ion leakage. Also, increasing the level of salinity stress up to 12 ds m.sup.- 1 affected the amount of chlorophyll, root length and leaf total area, all of which reduced significantly compared to plants under no stress. However, many studies have highlighted the application of compounds that reduce the negative effects of stress and increase plant resistance and tolerance against stresses. In this study, the application of SA even at low concentration (0.5 mM) could neutralize the negative effects of salinity stress in the Rosa damascena. In this regard, the results showed that salinity increases the activity of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and the concentration of proline, protein and glycine betaine (GB). Overexpression of antioxidant genes (Ascorbate Peroxidase (APX), CAT, Peroxidase (POD), Fe-SOD and Cu-SOD) showed an important role in salt tolerance in Damascus rose. In addition, 0.5 mm SA increased the activity of enzymatic and non-enzymatic systems and increased salinity tolerance. The change in weather conditions due to global warming and increased dryness contributes to the salinization of the earth's surface soils. Therefore, it is of particular importance to measure the threshold of tolerance of roses to salinity stress and the effect of stress-reducing substances in plants. In this context, SA has various roles such as increasing the content of pigments, preventing ethylene biosynthesis, increasing growth, and activating genes involved in stress, which modifies the negative effects of salinity stress. Also, according to the results of this research, even in the concentration of low values, positive results can be obtained from SA, so it can be recommended as a relatively cheap and available material to improve production in saline lands.
Salinity is a major abiotic stress negatively affecting plant growth and consequently crop production. The effects of short-term salt stress were evaluated on seedlings of three globally important ...Brassica crops-Chinese cabbage (
ssp.
), white cabbage (
var.
), and kale (
var.
)-with particular focus on phenolic acids. The physiological and biochemical stress parameters in the seedlings and the levels of three main groups of metabolites (total glucosinolates, carotenoids, and phenolics) and individual phenolic acids were determined. The salt treatments caused a dose-dependent reduction in root growth and biomass and an increase in stress parameters (Na
/K
ratio, reactive oxygen species (ROS) and glutathione (GSH)) in all seedlings but most prominently in Chinese cabbage. Based on PCA, specific metabolites grouped close to the more tolerant species, white cabbage and kale. The highest levels of phenolic acids, particularly hydroxycinnamic acids, were determined in the more tolerant kale and white cabbage. A reduction in caffeic, salicylic, and 4-coumaric acid was found in Chinese cabbage and kale, and an increase in ferulic acid levels was found in kale upon salinity treatments. Phenolic acids are species-specific among Brassicaceae, and some may participate in stress tolerance. Salt-tolerant varieties have higher levels of some phenolic acids and suffer less from metabolic stress disorders under salinity stress.
The creation of salt-tolerant wheat genotypes can provide a basis for sustainable wheat production in areas that are particularly sensitive to the impacts of climate change on soil salinity. This ...study aimed to select salt-tolerant wheat genotypes that could serve as a genetic resource in breeding for salinity tolerance. A two-year experiment was established with 27 wheat genotypes, grown in salinity stress and non-stress conditions. Agronomic parameters (plant height, spike weight, number of grains per spike, thousand grain weight, and grain yield/plant) were analyzed in the phenophase of full maturity, while biochemical parameters (DPPH radical scavenging activity and total phenolic content) were tested in four phenophases. Grain yield/plant was the most sensitive parameter to salinity, with a 31.5% reduction in value. Selection based on salt tolerance indices (STI, MP, and GMP) favored the selection of the genotypes Renesansa, Harmonija, Orašanka, Bankut 1205, KG-58, and Jugoslavija. Based on YI (1.30) and stability analysis, the genotype Harmonija stands out as the most desirable genotype for cultivation in saline conditions. The presence of positive correlations between grain yield/plant and biochemical parameters, in all phenophases, enables the selection of genotypes with high antioxidant activity and high yield potential, even in the early stages of plant development.
Self-sealing performance of compacted bentonite is the key to reduce the threat posed by high-level radioactive waste in deep geological repositories to the geological environment and human habitat. ...However, it will be inevitably affected by the field groundwater chemistry, thus influencing the water retard capacity of the engineering barrier. For this reason, a series of hydration tests with simulated radial technological voids were conducted on compacted bentonite, and the evolutionary process was visualized using a custom-designed device. Effect of groundwater concentration was considered using synthetic water with different total dissolved solids. Results show that the filling of the technological void is actually a free swell process, and the fast increase of crack area coincided with the rapid expansion of the primary swelling. As the salinity increased, the crack development extent decreased in terms of both propagation rate and the maximum crack area and so was the time duration to reach the peak of cracking. However, in the cases of higher salinity, a slower sealing rate and longer sealing period were observed. At the end of the hydration test, the water content decreased as the water salinity increased at all sample locations; the dry densities of the inner and middle sections were larger than that in the outer section. Those observations are of great importance in the evaluation of the self-sealing capacity in the field of water chemistry conditions and thus guide the design of the engineering barrier.
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