Levels Of Salinity Stress Research Articles

Reactive oxygen species (ROS) scavenging and methylglyoxal (MG) detoxification confers salinity tolerance in mustard cultivars inoculated with Piriformospora (Serendipita) indica

Salinization has become a major concern for the growth and development of plants, resulting in significant crop losses. Beneficial microbial symbionts are utilized as promising tools in alleviation of adverse effects of salt stress. Piriformospora (Serendipita) indica is one of the cost-effective, eco-friendly, and stress relieving biostimulant that positively regulates the growth of a broad host range of plants. The present study was to investigate the impact of P. indica on Indian mustard (Brassica juncea L.) cultivars (Pusa Jaikisan and Pusa Bold) under different levels of salinity stress (0, 50, 100, 150, 200 and 300 mM NaCl) by analyzing morphological, physiological and biochemical attributes. Results revealed that the plant biomass, chlorophyll content, and relative water content were reduced and Na+ and Cl‒ ions uptake increased with increasing NaCl concentrations. The maximum reduction in the measured traits was observed at 300 mM NaCl in both cultivars [tolerant (Pusa Jaikisan) and sensitive (Pusa Bold)]. Additionally, the oxidative stress markers (TBARS, MG, H2O2, and EL) accumulation were increased with increasing salt concentrations. However, P. indica colonization enhanced the plant performance by improving the biomass, chlorophyll, and water content, and reduced levels of oxidative stress markers (TBARS, MG, H2O2, and EL) in both cultivars comparatively more in Pusa Jaikisan than Pusa Bold under salinity stress. Additionally, the maximum activities of methyl glyoxal detoxifying enzymes (Gly I & Gly II) along with the components of ROS scavenging machinery (SOD, APX, GPX, GR, AsA, and GSH) in the P. indica colonized plants conferred salt tolerance in comparison to non-colonized cultivars under salinity stress. The results indicate that P. indica promotes the growth and tolerance of mustard plants under salinity stress, thus providing opportunity for further assessment in terms of use in sustainable agriculture.

VETIVER (VETIVERIA ZIZANIOIDES L.) ECOTYPES ASSESSMENT FOR SALINITY TOLERANCE

Vetiver is one of the essential oil-producing plants, commonly called vetiver oil. With a deep, broad, and thick root system, the species is characteristically well-adapted to various environmental stresses, including salinity. The presented study strived to evaluate several vetiver ecotypes under diverse salinity stress conditions and identify the best with enhanced salinity tolerance. The said study continued in a completely randomized design (CRD) with factorial arrangement and two factors. The first factor was salinity stress comprising six varying levels, i.e., control (without salinity) and saline soils with 4, 8, 12, 16, and 20 dsm-1. The second factor consisted of three vetiver ecotypes: Bogor, Bojonegoro, and Padang. The results revealed that salinity stress levels, ecotypes, and their interactions significantly affected the growth, physiological, and oil yield traits, such as plant height, leaf area, number of tillers, chlorophyll a and b, root length and volume, and oil yield. Salinity stress at 16 dsm-1 significantly impacted plant growth but enhanced chlorophyll a and b content. The ecotype Bojonegoro had better canopy growth, while the ecotype Padang had better root growth, resulting in higher oil production compared with the ecotype Bojonegoro. The ecotype Bojonegoro with 16 dsm-1 salinity stress significantly increased chlorophyll a and b content, and the ecotype Padang showed the highest oil production without salinity stress compared with salinity stress conditions.

SALINITY TOLERANCE OF QUINOA (CHENOPODIUM QUINOA WILLD.) GENOTYPES TO ELEVATED NACL CONCENTRATIONS AT GERMINATION AND SEEDLING STAGES

Evaluating quinoa genotypes for salinity tolerance at germination and seedling stages is a prerequisite for plant breeders. Thus, the scrutiny of 19 quinoa genotypes at different salinity levels under controlled laboratory and greenhouse conditions occurred at the germination and seedling stages. This study aimed to identify the most tolerant genotypes to elevated salinity levels at germination and seedling stages and to determine the traits of a robust association with salinity tolerance using a factorial experiment based on a randomized complete block design in three replications. The four salinity solutions used were zero (control), 3000, 6000, and 9000 ppm NaCl. Increasing concentrations of NaCl caused a gradual and significant decrease for all studied traits except mean germination time, which significantly increased. At all salinity-stress levels (3000, 6000, and 9000 ppm NaCl), the studied 19 genotypes underwent classification based on their salinity tolerance index (STI) into three categories, i.e., tolerant, moderately tolerant, and sensitive. The four most salinitytolerant quinoa genotypes under all studied salinity-stress conditions were Rainbow-2, Ql3, RH, and KvlSRA2. The strongest correlations were between STI and each of seedling length, root length, seedling fresh weight, seedling vigor index I, and seedling vigor index II under 3000 ppm; germination percentage, speed germination index, seedling extent, root length, seedling fresh weight, and seedling vigor index II under 6000 ppm; and shoot length and seedling vigor index I under 9000 ppm salinity concentration level. Traits showing sturdy correlations with STI, high heritability estimates, high expected genetic advance, and wide phenotypic and genotypic variability were seedling dry weight, seedling fresh weight, seedling vigor index II, and speed germination index at all salinity stress concentrations; they are recommendable as selection criteria for salinity tolerance in quinoa at germination and seedling stages.

Composition of fungal communities upon multiple passaging of rhizosphere microbiome for salinity stress mitigation in Vigna radiata.

The top-down approach of microbiome-mediated rhizosphere engineering has emerged as an eco-friendly approach for mitigating stress and enhancing crop productivity. It has been established to mitigate salinity stress in Vigna radiata using multi-passaging approach. During the process of acclimatization under increasing levels of salinity stress, the structure of rhizospheric microbial community undergoes dynamic changes, while facilitating stress mitigation in plants. In this study, using ITS-based amplicon sequencing, the dynamics of rhizosphere fungal community was unravelled over successive passages under salt stress in Vigna radiata. Clear shifts were evident among the fungal community members under stress and non-stress conditions, upon application of acclimatized rhizosphere microbiome in Vigna radiata across successive passages. These shifts correlated with enhanced plant biometrics and reduced stress marker levels in plant. Significant changes in the fungal community structure were witnessed in rhizosphere across passaging cycles under salinity stress, which possibly facilitated stress mitigation in Vigna radiata.

Morphological responses of three contrasting Soybean (Glycine max (L.) Merrill) genotypes under different levels of salinity stress in the coastal region of Bangladesh

Soil salinity, a global environmental issue, inhibits plant development and production. Soybean is an economically important legume crop whose yield and quality are highly affected by excessive levels of salt in the root zone. A factorial experiment was conducted in a net house from October 2019 to January 2020 to evaluate the performance of three distinct soybean genotypes under varying levels of salinity stress. The experiment followed a completely randomized design (CRD) with three replications. Three soybean cultivars, namely BINA Soybean 1, BINA Soybean 2, and BINA Soybean 4 were used in this experiment. The soil salinity treatments were 0 mM NaCl, 50 mM NaCl, 100 mM NaCl, 150 mM NaCl, and 200 mM NaCl. The electrical conductivity (EC) of the soil sample was 0.91dS/m. Six seeds were sown 3 cm deep in each pot. A total of 45 pots were used in this experiment. The performance of each variety was evaluated based on its germination percentage, time of germination, no. of branches/plant, no. of leaves/plant, no. of flowers/plant, plant height (cm), no. of pods/plant, pod length (cm), seeds/pod, and root length (cm). Based on the results obtained from this research trial, it can be inferred that the BINA Soybean 2 variety along with 0 mM NaCl, 50 mM NaCl, and 100 mM NaCl treatments exhibited superior performance in all parameters compared to the other varieties. This study provides clear evidence that the soybean, particularly the BINA Soybean 2 variety, holds significant promise as a crop suitable for coastal regions. Furthermore, it suggests that the cultivation of soybeans in such areas could potentially enhance agricultural productivity, particularly in the presence of mild saline conditions. Nevertheless, it exhibits limited growth potential in environments with elevated salinity levels.

Enhancing Chickpea (Cicer arietinum L.) Tolerance to Salinity through Plant Growth Regulators

During the period of 2020-21, a research study was carried out at the Plant Protective Culture Unit within the semi-controlled environmental settings of the Bangladesh Agricultural Research Institute. The aim of the study was to mitigate the negative impacts of salinity stress on chickpea by applying various concentrations of salicylic acid (SA) and gibberellic acid (GA3). Plants were subjected to four different levels of salinity stress, including a control group, mild stress, moderate stress, and severe stress. This was achieved by irrigating them with four varying concentrations of saline water (5, 7.5, 10 and 12.5 dSm-1) starting from the 14th day after sowing (DAS) and continuing until maturity at 100 DAS. On the other hand, the control plants received regular irrigation with tap water. Two concentrations of salicylic acid (SA) specifically 200 ppm and 400 ppm, along with gibberellic acid (GA3) at 10 ppm and 20 ppm, were administered as a foliar spray once a week, commencing at 20 days after sowing (DAS) and continuing until the flowering stage. Data related to chlorophyll levels in the leaves and water-related traits, including relative water content (RWC) and water retention capacity (WRC) were collected seven days after the foliar spray of these plant growth regulators at the flowering stage. Additionally, measurements of total dry weight, yield, and various yield-contributing factors were taken at the point of maturity. The results indicated that chickpea suffered adverse consequences due to salinity stress which included a reduction in chlorophyll content, a decrease in relative water content, a decline in water retention capacity, a decrease in total dry weight and a lower overall yield. However, the foliar application of different doses of salicylic acid (SA) and gibberellic acid (GA3) under varying levels of salinity stress had beneficial effects in alleviating the impact of salinity stress. Interestingly, it was observed that lower concentrations of SA at 200 ppm and GA3 at 10 ppm were more effective in mitigating the adverse effects of salinity stress and improving salinity tolerance in chickpea, especially under mild salinity stress conditions (5 dSm-1) as evidenced by the positive influence on the parameters mentioned above.

Effects of Salt Stress on Grain Yield and Quality Parameters in Rice Cultivars with Differing Salt Tolerance.

Rice yield and grain quality are highly sensitive to salinity stress. Salt-tolerant/susceptible rice cultivars respond to salinity differently. To explore the variation in grain yield and quality to moderate/severe salinity stress, five rice cultivars differing in degrees of salt tolerance, including three salt-tolerant rice cultivars (Lianjian 5, Lianjian 6, and Lianjian 7) and two salt-susceptible rice cultivars (Wuyunjing 30 and Lianjing 7) were examined. Grain yield was significantly decreased under salinity stress, while the extent of yield loss was lesser in salt-tolerant rice cultivars due to the relatively higher grain filling ratio and grain weight. The milling quality continued to increase with increasing levels. There were genotypic differences in the responses of appearance quality to mild salinity. The appearance quality was first increased and then decreased with increasing levels of salinity stress in salt-tolerant rice but continued to decrease in salt-susceptible rice. Under severe salinity stress, the protein accumulation was increased and the starch content was decreased; the content of short branched-chain of amylopectin was decreased; the crystallinity and stability of the starch were increased, and the gelatinization temperature was increased. These changes resulted in the deterioration of cooking and eating quality of rice under severe salinity-stressed environments. However, salt-tolerant and salt-susceptible rice cultivars responded differently to moderate salinity stress in cooking and eating quality and in the physicochemical properties of the starch. For salt-tolerant rice cultivars, the chain length of amylopectin was decreased, the degrees of order of the starch structure were decreased, and pasting properties and thermal properties were increased significantly, whereas for salt-susceptible rice cultivars, cooking and eating quality was deteriorated under moderate salinity stress. In conclusion, the selection of salt-tolerant rice cultivars can effectively maintain the rice production at a relatively high level while simultaneously enhancing grain quality in moderate salinity-stressed environments. Our results demonstrate specific salinity responses among the rice genotypes and the planting of salt-tolerant rice under moderate soil salinity is a solution to ensure rice production in China.

Investigating the dynamic responses of Aegilops tauschii Coss. to salinity, drought, and nitrogen stress: a comprehensive study of competitive growth and biochemical and molecular pathways.

Aegilops tauschii (Coss.) is a highly deleterious, rapidly proliferating weed within the wheat, and its DD genome composition exhibits adaptability toward diverse abiotic stresses and demonstrates heightened efficacy in nutrient utilization. Current study investigated different variegated impacts of distinct nitrogen concentrations with varied plant densities, scrutinizing the behavior of Ae. tauschii under various salinity and drought stress levels through multiple physiological, biochemical, and molecular pathways. Different physiological parameters attaining high growth with different plant density and different nitrogen availability levels increased Ae. tauschii dominancy. Conversely, under the duress of salinity and drought, Ae. tauschii showcased an enhanced performance through a comprehensive array of physiological and biochemical parameters, including catalase, peroxidase, malondialdehyde, and proline content. Notably, salinity-associated traits such as sodium, potassium, and the sodium-potassium ratio exhibited significant variations and demonstrated remarkable tolerance capabilities. In the domain of molecular pathways, the HKT and DREB genes have displayed a remarkable upregulation, showcasing a comparatively elevated expression profile in reaction to different levels of salinity and drought-induced stress. Without a doubt, this information will make a substantial contribution to the understanding of the fundamental behavioral tendencies and the efficiency of nutrient utilization in Ae. tauschii. Moreover, it will offer innovative viewpoints for integrated management, thereby enabling the enhancement of strategies for adept control and alleviation.

COMBINING ABILITY FOR YIELD, OIL CONTENT, AND PHYSIO-BIOCHEMICAL CHARACTERS OF CANOLA (BRASSICA NAPUS L.) UNDER SALT STRESS CONDITIONS

Creating a half-diallel cross succeeded among seven diverse canola genotypes. The obtained 21 F1 hybrids with their seven parents underwent three salinity stress levels exposure—3.91 dsm1 (Normal), 6.24 dsm-1 (S1), and 7.81 dsm-1 (S2) —during the 2020/2021 growing seasons. Salinity treatments significantly reduced days to 50% flowering, plant height, number of primary branches, pods/plant, 1000-seed weight, seed yield/plant, seed oil content, relative water content, calcium, potassium, and the ratio between K+ and Na+ compared with a normal condition. Proline content, osmotic pressure, and Na+ were considerably higher under salinity stress conditions. Highly significant differences showed among the parents and hybrids for all traits across the tested environments. General (GCA) and specific (SCA) combining ability effects were highly significant for all attributes. The parental genotypes Serw4 and Pactol resulted as good general combiners for increased seed oil content (SOC), seed yield/plant (SYPP), and some of its components in research environments. The hybrid combinations H2/S × Serw4 and Serw4 × Serw6 were good specific combiners for days to first flower (DTF), number of primary branches (NPB), number of pods per plant (NP), a thousand seed weight (TSW), seed yield per plant (SYPP), seed oil content (SOC), proline content (ProC), Ca++, and K+/Na+. The SDS-PAGE analysis of seed proteins indicated high levels of genetic variability and revealed some vital biochemical markers for salt tolerance.

Effect of salt stress on morpho-physiological and anatomical attributes of Salix clones

Abstract The aim of the study was to assess and quantify the impact of salt stress on key morpho-physiological traits that influence biomass production in Salix clones. In February 2021, a pot experiment was conducted using stem cuttings of five selected Salix clones. The experiment followed a Factorial Completely Randomized Design (CRD) with four replications. The clones were subjected to different levels of NaCl treatments (0, 20, 40, 60, and 80 mM) during the active growth period. The observations on growth and physiological characteristics of clones were recorded at an interval of two months after initiation of salinity treatments i.e., May, July and October. However, the biomass parameters were recorded at the end of experiment. All the growth and biomass traits showed significant reduction with increase in salinity treatments. Among physiological traits significant reduction were observed in total chlorophyll, carotenoids and relative water content, while salinity stress raised the content of proline, total soluble sugar, total soluble protein and Na+/K+ ratio in all the clones. The enzymatic activities of POD and SOD increased in all the clones when subjected to higher levels of salinity stress. On the basis of overall mean performance, clone UHF-03 showed optimum growth and biomass accumulation at 80 mM and was found to be the most tolerant to salinity stress. SEM and EDS mapping confirmed anatomical changes and Na accumulations in the roots and leaves of Salix in response to salinity stress.

Jasmonic acid boosts the salt tolerance of kidney beans (Phaseolus vulgaris L.) by upregulating its osmolytes and antioxidant mechanism.

As a lipid-derived compound, jasmonic acid (JA) regulates growth and defense against environmental stresses. An exogenous foliar JA application was investigated in our study (HA; 0.5 mM) on kidney bean plants (Phaseolus vulgaris L.) grown under different salinity stress concentrations (0, 75, and 150 mM NaCl). According to the results, salt concentrations were related to an increase in malondialdehyde (MDA) levels, whereas they declined the chlorophyll content index. In contrast, JA application decreased the level of MDA but increased the chlorophyll content index. Moreover, increasing salinity levels increased proline, phenolic compounds, flavonoids, free amino acid concentrations, and shikimic acid concentrations, as well as the activities of polyphenol oxidase (PPO), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD). In addition, JA applications further increased their concentrations with increasing salinity stress levels. JA application increases salt-induced osmolytes and non-enzymatic antioxidants while increasing enzymatic antioxidant activity, suggesting kidney beans have a strong antioxidant mechanism, which can adapt to salinity stress. Our results showed that exogenous JA foliar applications could enhance the salt tolerance ability of kidney bean plants by upregulating their antioxidant mechanism and osmolytes.

Germination and Growth Parameters in Sorghum Cultivars (Sorghum bicolor L.) Effected by Boron Application under Salinity Stress

The aim of this research is investigating the effects of boron on the germination and growth of three sorghum cultivars at different salinity stress levels. The experiment was arranged as four replications according to the factorial experimental design in completely random blocks The three sorghum (Sorghum bicolor L.) cultivars (Erdurmuş, Uzun and Gözde 80) selected for the genetic material. NaCl compound was utilized as salt source and solutions were prepared at concentrations of 0-75-150 mM. Boron was applied as H3BO3 at 0-5-10-15 mM. In general regarding growth parameters, the values obtained in Gözde 80 cultivar were determined as the highest averages. Whereas the salinity levels effect was examined in this study, a decrease was determined in the parameters measured as the level of the stress factor increased. Salinity had a high adverse effect at the 150 mM level, and as expected the highest averages were obtained in the control treatments. Low-dose boron applications have possitive effects on germination and growth parameters in this experiment. Therewithal under salinity stress conditions, low-dose boron applications showed affirmative efficacy compared to the control of each condition. In this experiment, determined that boron applications reduce this effect under salinity stress conditions that sorghum seeds may encounter during the germination period, but the boron dose level to be applied should be properly controlled.

Osmoprotectants play a major role in the Portulaca oleracea resistance to high levels of salinity stress-insights from a metabolomics and proteomics integrated approach.

Purslane (Portulaca oleracea L.) is a non-conventional food plant used extensively in folk medicine and classified as a multipurpose plant species, serving as a source of features of direct importance to the agricultural and agri-industrial sectors. This species is considered a suitable model to study the mechanisms behind resistance to several abiotic stresses including salinity. The recently achieved technological developments in high-throughput biology opened a new window of opportunity to gain additional insights on purslane resistance to salinity stress-a complex, multigenic, and still not well-understood trait. Only a few reports on single-omics analysis (SOA) of purslane are available, and only one multi-omics integration (MOI) analysis exists so far integrating distinct omics platforms (transcriptomics and metabolomics) to characterize the response of purslane plants to salinity stress. The present study is a second step in building a robust database on the morpho-physiological and molecular responses purslane to salinity stress and its subsequent use in attempting to decode the genetics behind its resistance to this abiotic stress. Here, the characterization of the morpho-physiological responses of adult purslane plants to salinity stress and a metabolomics and proteomics integrative approach to study the changes at the molecular level in their leaves and roots is presented. Adult plants of the B1 purslane accession lost approximately 50% of the fresh and dry weight (from shoots and roots) whensubmitted to very high salinity stress (2.0 g of NaCl/100 g of the substrate). The resistance to very high levels of salinity stress increases as the purslane plant matures, and most of the absorbed sodium remains in the roots, with only a part (~12%) reaching the shoots. Crystal-like structures, constituted mainly by Na+, Cl-, and K+, were found in the leaf veins and intercellular space near the stoma, indicating that this species has a mechanism of salt exclusion operating on the leaves, which has its role in salt tolerance. The MOI approach showed that 41 metabolites were statistically significant on the leaves and 65 metabolites on the roots of adult purslane plants. The combination of the mummichog algorithm and metabolomics database comparison revealed that the glycine, serine, and threonine, amino sugar and nucleotide sugar, and glycolysis/gluconeogenesis pathways were the most significantly enriched pathways when considering the total number of occurrences in the leaves (with 14, 13, and 13, respectively) and roots (all with eight) of adult plants; and that purslane plants employ the adaptive mechanism of osmoprotection to mitigate the negative effect of very high levels of salinity stress; and that this mechanism is prevalent in the leaves. The multi-omics database built by our group underwent a screen for salt-responsive genes, which are now under further characterization for their potential to promote resistance to salinity stress when heterologously overexpressed in salt-sensitive plants.

Morphophysiological Responses of Oat (Avena sativa L.) Genotypes from Pakistan’s Semiarid Regions to Salt Stress

Soil salinity is a major constraint to modern agriculture, with around 20% of the previously irrigated area becoming salt affected. Identifying suitable salt stress-tolerant genotypes based on their agronomic and physiological traits remains a herculean challenge in forage-type Oat (Avena sativa L.) breeding. The present study was designed to investigate the response of oat crop plants against the salt (NaCl) stress in Mardan, Pakistan. The experiment was carried out in complete randomized design (CRD) with two factors trail comprising of the performance of four different genotypes of oat (NARC oat, PARC oat, Green Gold and Islamabad oat) in response to four levels of saline stress (0, 25, 50 and 75 mmol L-1 NaCl). Plant growth and physiological parameters including germination (G, %); fresh shoot weight (FSW, g); fresh root weight (FRW, g); chlorophyll-a, chlorophyll-b, total chlorophyll, and total carotenoids were analyzed for identifying salt tolerance. Germination (%) of oat genotypes was negatively affected by higher salt stress. Mean values showed that maximum germination (57.5%) was recorded for control while minimum germination (48.75%) was recorded for 25 mmol L-1 NaCl and that maximum germination (58%) was recorded for PARC oat. The root and shoot fresh weight of all genotypes declined with increasing salt stress, while NARC and Green Gold oat showed considerably higher values than the other genotypes. Although chlorophyll and carotenoids were found to be negatively affected by increasing salt concentrations, NARC and Green Gold oat genotypes performed considerably better at 75 mmol L-1 NaCl when compared to the other genotypes. Based on the mean shoot dry weight ratio ± one standard error, the four Oat genotypes were categorized as salt-tolerant (Green Gold), moderately tolerant (PARC and NARC), and salt-sensitive (Islamabad). The more salt-tolerant genotype (Green Gold) demonstrated relatively high salinity tolerance and may be useful for developing high-yielding oat hybrids in future breeding programs under salt stress conditions.

Exploration of plant growth promoting traits and regulatory mechanisms of Bacillus anthracis PM21 in enhancing salt stress tolerance in maize.

Bacillus species have been reported to reduce the negative effects of salt stress on plants; the involvement of Bacillus anthracis PM21 and the internal mechanisms involved in this process are unclear. The effects of PM21 inoculation on maize plants under salt stress were investigated in this study. The study aimed to assess the ability of Bacillus anthracis PM21 to endure high levels of salinity stress while preserving the concentration of plant growth regulators. The biomass, photosynthetic pigments, relative water content (RWC), antioxidants, osmoprotectants, inorganic ion contents, regulation of plant hormones and expression of antioxidants enzyme encoded genes were investigated under normal and salinity stress conditions. Bacillus anthracis PM21 produced a significant amount of 1-aminocyclopropane-1-carboxylate deaminase enzyme (ACC deaminase) and exopolysaccharides (EPS) under salt stress and normal conditions. PM21 also produced plant growth stimulants including indole acetic acid, gibberellic acid (GA3), kinetin, and siderophore under salinity stress and normal conditions. Under salt stress, PM21 inoculation markedly increased plant growth indices, stimulate antioxidant enzyme mechanisms, osmoprotectants, and chlorophyll content. The use of qRT-PCR to analyze the transcription of targeted genes indicated greater expression of antioxidant-encoded genes and inferred their possible function in salinity stress tolerance. Our findings shed light on the functions of PM21 and its regulatory mechanisms in plant salt stress tolerance, as well as the importance of PM21 in this process. This study will provide a thorough analysis of the theoretical framework for adopting PM21 in agricultural production as an eco-friendly method to enhance crop growth and yield under salinity stress.

Varietal Performance of Maize (Zea mays L.) Strains Under Saline Conditions

Crop yields are highly affected due to physiochemical properties of soil and climatic conditions of the region. The yield of the crop is drastically impacted in terms of final economic product due to problems which occurs in life cycle of the plant under the stress conditions like, stunted growth, permanent wilting, and delay in leaf initiation as well as oxidative stresses at molecular level. Maize (Zea mays L.), widely used as staple food has an ample amount of fats and fibres. Salt stress decreases maize yield and in this regard a hydroponic study was carried out to screen maize genotypes against two salinity stress levels i.e., 10 mol m-3 NaCl and 100 mol m-3 NaCl under hydroponic conditions. Nine (09) hybrid genotypes, i.e., Pioneer 3335 (V1), Pioneer 32F10 (V2), Syngenta 8441 (V3), Pioneer: 33H25 (V4), Pioneer: 3233 (V5), Monsanto 6142 (V6), Syngenta 8711 (V7), Monsanto 6528 (V8), Pioneer 31P41 (V9) were selected for experiment. Statistically, the analysis showed the highest root-shoot length, root fresh-dry weight, and shoot fresh-dry weight with V3 (Syngenta 8441) and the minimum with V1 (Pioneer 3335). The results showed that root length increased by 35% shoot length increased by 34% while total length was enhanced by 34% in syngenta 8441. The results clearly depicted that the best suited variety for salt affected areas can be recommended as Syngenta 8441 whereas the least tolerant was Pioneer 3335 in terms of physiological, physical, and growth characteristics.

Effect of Plant Hormones on Antioxidant Response and Essential Oil Production of Peppermint (Mentha Piperita) at Different Levels of Salinity Stress

Effect of Plant Hormones on Antioxidant Response and Essential Oil Production of Peppermint (Mentha Piperita) at Different Levels of Salinity Stress

Co-application of Mycorrhiza and methyl jasmonate regulates morpho-physiological and antioxidant responses of Crocus sativus (Saffron) under salinity stress conditions

Salinity stress is the second most devastating abiotic factor limiting plant growth and yields. Climate changes have significantly increased salinity levels of soil. Besides improving the physiological responses under stress conditions, jasmonates modulate Mycorrhiza—Plant relationships. The present study aimed to evaluate the effects of methyl jasmonate (MeJ) and Funneliformis mosseae (Arbuscular mycorrhizal (AM) on morphology and improving antioxidant mechanisms in Crocus sativus L. under salinity stress. After inoculation with AM, pre-treated C. sativus corms with MeJ were grown under low, moderate, and severe salinity stress. Intense salinity levels damaged the corm, root, total leaf dry weight, and area. Salinities up to 50 mM increased Proline content and Polyphenol oxidase (PPO) activity, but MeJ increased this trend in proline. Generally, MeJ increased anthocyanins, total soluble sugars, and PPO. Total chlorophyll and superoxide dismutase (SOD) activity increased by salinity. The maximum catalase and SOD activities in + MeJ + AM were 50 and 125 mM, respectively, and the maximum total chlorophyll in –MeJ + AM treatment was 75 mM. Although 20 and 50 mM increased plant growth, using mycorrhiza and jasmonate enhanced this trend. Moreover, these treatments reduced the damage of 75 and 100 mM salinity stress. Using MeJ and AM can improve the growth of saffron under various ranges of salinity stress levels; however, in severe levels like 120 mM, this phytohormone and F. mosseae effects on saffron could be adverse.

Response of sesame (Sesamum indicum L.) to foliar-applied thiourea under saline conditions

Salt stress is among the most pervasive limitations for food production, which eventually results in negative financial, environmental and social consequences. Thiourea is a vital chemical which improves growth and yield of plants. Sesame (Sesamum indicum L.) is a crop of semi-arid and arid regions, whose medicinal and seed oil properties are well known. A pot experiment was carried out to examine the impact of thiourea on sesame plants exposed to saline conditions. Two cultivars of sesame, i.e., TH-5 and TH-6 were used. Two levels (0 and 70 mM) of salinity stress as well as two foliar-applied levels (water spray and 150 mM) of thiourea were maintained after 28 and 34 days of seed sowing, respectively. Data for various morphological and physiological attributes was taken after 56 days of seed sowing. The results showed that salinity stress diminished shoot mass along with root mass (fresh and dry) as well as shoot and root lengths. Of physiological parameters, chlorophyll and gas exchange attributes were also negatively affected by the salinity stress. Salinity stress escalated the activities of SOD and POD as well as the levels of MDA. Foliar-applied thiourea raised the contents of chlorophyll b, total chlorophyll and carotenoids of cv. TH-6 under salt stress. The activity of POD of both cultivars under control and salt stress conditions and root K+ concentration of cv.TH-5 under salt stress were also enhanced by thiourea. Overall, foliar application of thiourea mitigated the negative impacts of salinity on sesame.

Physiological and anatomical response of rice (Oryza sativa L.) ‘Hom Mali Daeng’ at different salinity stress levels

Abstract Soil salinity is a severe global stressor causing adverse impacts on irrigated land and drastically reducing crop yields, especially in rice, an important economic crop of Thailand. In this study, the impacts of salt stress on the anatomical and physiological features of 28-day-old rice (Oryza sativa L.) ‘Hom Mali Daeng’ were determined. Various NaCl concentrations (0, 50, 100, 150, and 200 mM) were applied every 2 days, with watering for 2 weeks. The results revealed that salinity stress inhibited the growth of rice. Leaf number, root size, fresh weight, and dry weight were significantly reduced. The electrolyte leakage percentage and malondialdehyde (MDA) content increased after treatment with high NaCl concentrations, while the SPAD unit and chlorophyll content were not significantly different between the control and NaCl treatments. Leaf anatomy changes were studied using freehand section and peeling techniques after salinity stress treatment. Lamina thickness in all treatments decreased, while cell wall and cuticle thickness increased. Stomatal density in all treatments significantly increased. Major vascular bundle, vessel, and phloem area of the 100 mM NaCl treatment were different when compared with the control and other treatments. The results provide information about the physiological and anatomical adaptation of ‘Hom Mali Daeng’ rice, which will be useful for further research in this and other rice cultivars.