Soil Application of Wheat Straw Vermicompost Enhances Morpho-Physiological Attributes and Antioxidant Defense in Wheat Under Drought Stress

With the provoked environmental constraints under extreme climatic events, a better understanding of plant responses to these environmental stresses helps in obtaining sustainable productivity. Wheat is a significant cereal crop for the burgeoning population; its yield is significantly limited by too little water in the rhizosphere. The ramifications of water deficiency on the wheat crop can be reduced by the application of vermicompost. With the objective to cope with drought stress, a wire-house experiment was established where seedlings of two cultivars, viz., Faisalabad-08 and Galaxy-13 (drought-tolerant and -sensitive cultivar, respectively) were grown in pots and exposed to mild drought (D1, 45% field capacity) and severe drought stress (D2, 30% field capacity). A control with well-watered condition (70% field capacity) was kept for comparison. Various application rates of wheat straw vermicompost (control (VT0), 4 t ha(-1) (VT1), 6 t ha(-1) (VT2), and 8 t ha(-1) (VT3)), were used in soil-filled pots under drought and control treatments. Our data depicted that compared with control, drought treatments recorded a significant reduction in morpho-physiological and biochemical attributes with maximum reduction under severe drought conditions. Nonetheless, it was observed that soil application of vermicompost, particularly at a high rate, ameliorated the negative effects of drought. Under severe drought conditions, a significant and positive influence on morphological and physiological traits was recorded for VT3 treatment, which increased root and shoot length by 27.55 and 27.85%, root and shoot fresh weight by 26.98 and 28.20%, root and shoot dry weight by 40 and 50.05%, and photosynthesis and transpiration rate by 27.65 and 49.25%, respectively, on average of two cultivars. Similarly, VT3 also significantly ameliorated the adverse effect of drought by enhancing the antioxidant enzyme activities as it increased superoxide dismutase activity by 14.28%, peroxidase by 27.28%, and catalase by 50% compared to the control treatment. Among cultivars, Faisalabad-2008 showed comparatively more resistance against drought stress. The findings of this work revealed that drought drastically reduced the growth and productivity of wheat; however, soil-applied vermicompost positively influenced the performance of wheat cultivars.Taif University, Taif, Saudi Arabia [TURSP-2020/94]The current work was funded by the Taif University Researchers Supporting Project Number (TURSP-2020/94), Taif University, Taif, Saudi Arabia

Salinity Duration Differently Modulates Physiological Parameters and Metabolites Profile in Roots of Two Contrasting Barley Genotypes

Hordeum maritimum With. is a wild salt tolerant cereal present in the saline depressions of the Eastern Tunisia, where it significantly contributes to the annual biomass production. In a previous study on shoot tissues it was shown that this species withstands with high salinity at the seedling stage restricting the sodium entry into shoot and modulating over time the leaf synthesis of organic osmolytes for osmotic adjustment. However, the tolerance strategy mechanisms of this plant at root level have not yet been investigated. The current research aimed at elucidating the morphological, physiological and biochemical changes occurring at root level in H. maritimum and in the salt sensitive cultivar Hordeum vulgare L. cv. Lamsi during five-weeks extended salinity (200 mM NaCl), salt removal after two weeks of salinity and non-salt control. H. maritimum since the first phases of salinity was able to compartmentalize higher amounts of sodium in the roots compared to the other cultivar, avoiding transferring it to shoot and impairing photosynthetic metabolism. This allowed the roots of wild plants to receive recent photosynthates from leaves, gaining from them energy and carbon skeletons to compartmentalize toxic ions in the vacuoles, synthesize and accumulate organic osmolytes, control ion and water homeostasis and re-establish the ability of root to grow. H. vulgare was also able to accumulate compatible osmolytes but only in the first weeks of salinity, while soon after the roots stopped up taking potassium and growing. In the last week of salinity stress, the wild species further increased the root to shoot ratio to enhance the root retention of toxic ions and consequently delaying the damages both to shoot and root. This delay of few weeks in showing the symptoms of stress may be pivotal for enabling the survival of the wild species when soil salinity is transient and not permanent

Long-term mannitol-induced osmotic stress leads to stomatal closure, carbohydrate accumulation and changes in leaf elasticity in Phaselous vulgaris leaves

The effect of long-term osmotic stress was investigated in leaves of two common bean lines, with contrasting tolerance: Flamingo (tolerant) and coco blanc (sensitive). Water relations, organic solute, ion accumulation and amino acids content as well as osmotic adjustment (OA) were studied during an extended exposure to osmotic stress. Osmotic stress was applied by means of 50 mM mannitol for 15 days. At the end of the stress period, both osmotic potential at full turgor (psi(100)) and at turgor loss point (psi(0)) decreased significantly in stressed plants compared with the control. The decrease being greater in the sensitive line, showed a greater OA compared with flamingo. Sugars contents increased in stressed plants and seem to be the major components of osmotic adjustment in stressed common bean leaves. The increase was more marked in coco blanc. Osmotic stress tolerance could thus not be associated with higher OA. The possible role of decreased leaf cell elasticity (epsilon(max)) is discussed in relation to osmotic stress tolerance in this species.This work was supported by the AQUARHIZ Project: “Modulation of plant-bacteria interactions to enhance tolerance to water deficit for grain legumes in the Mediterranean dry lands” PT6 Project INCO-CT-2004-509115, and by the Tunisian Ministry of Higher Education and Scientific Research (LR10CBBC02)

Epidemiology of Chlamydia trachomatis in the Middle East and north Africa: a systematic review, meta-analysis, and meta-regression.

BACKGROUND: The epidemiology of Chlamydia trachomatis in the Middle East and north Africa is poorly understood. We aimed to provide a comprehensive epidemiological assessment of C trachomatis infection in the Middle East and north Africa. METHODS: We did a systematic review of C trachomatis infection as well as a meta-analysis and meta-regression of C trachomatis prevalence. We searched PubMed and Embase, as well as regional and national databases up to March 13, 2019, using broad search terms with no language or year restrictions. Any document or report including biological measures for C trachomatis prevalence or incidence was eligible for inclusion. We extracted all measures of current (genital or rectal), recent, and ever infection with C trachomatis. We estimated pooled average prevalence in different populations using random-effects meta-analysis. Factors associated with prevalence and sources of between-study heterogeneity were determined using meta-regression. FINDINGS: We identified a total of 1531 citations, of which 255 reports contributed to 552 C trachomatis prevalence measures from 20 countries. No incidence measures were identified. Pooled prevalence of current genital infection was 3·0% (95% CI 2·3-3·8) in general populations, 2·8% (1·0-5·2) in intermediate-risk populations, 13·2% (7·2-20·7) in female sex workers, 11·3% (9·0-13·7) in infertility clinic attendees, 12·4% (7·9-17·7) in women with miscarriage, 12·4% (9·4-15·7) in symptomatic women, and 17·4% (12·5-22·8) in symptomatic men. Pooled prevalence of current rectal infection was 7·7% (4·2-12·0) in men who have sex with men. Substantial between-study heterogeneity was found. Multivariable meta-regression explained 29·0% of variation. Population type was most strongly associated with prevalence. Additional associations were found with assay type, sample size, country, and sex, but not with sampling methodology or response rate (about 90% of studies used convenience sampling and >75% had unclear response rate). There was no evidence for temporal variation in prevalence between 1982 and 2018. INTERPRETATION: C trachomatis prevalence in the Middle East and north Africa is similar to other regions, but higher than expected given its sexually conservative norms. High prevalence in infertility clinic attendees and in women with miscarriage suggests a potential role for C trachomatis in poor reproductive health outcomes in this region. FUNDING: National Priorities Research Program from the Qatar National Research Fund (a member of Qatar Foundation)

Drought and salinity: A comparison of their effects on the ammonium‐preferring species Spartina alterniflora

Drought and salinity are the most serious environmental factors affecting crop productivity worldwide; hence, it is important to select and develop both salt- and drought-tolerant crops. The perennial smooth cordgrass Spartina alterniflora Loisel is unusual in that it is highly salt-tolerant and seems to prefer ammonium (NH4+) over nitrate (NO3−) as an inorganic N source. In this study, we determined whether Spartina's unique preference for NH4+ enhances performance under salt and drought stress. Greenhouse experiments were conducted to compare the interactive effects of N source, salinity, and low water availability on plant performance (growth and antioxidant metabolism). Drought significantly reduced growth and photosynthetic activity in S. alterniflora, more so with NH4+ than NO3−; in contrast, NH4+ enhanced growth under high salinity. The increased tolerance of S. alterniflora to salt stress in the presence of NH4+ was linked to a high level of antioxidant enzyme activity, combined with low MDA content, EL, and H2O2 production. In contrast, drought stress negated the growth advantages for S. alterniflora exposed to salt stress in the presence of NH4+. The susceptibility of S. alterniflora to drought was partly due to reduced antioxidant enzyme activities, thereby reducing the defense against the oxidative damages induced by osmotic stress. In conclusion, in contrast to salt stress, drought stress negates the beneficial effects of ammonium as an N source in the C4 plant Spartina alterniflora.info:eu-repo/semantics/publishedVersio

Zinc oxide nanoparticles alleviates the adverse effects of cadmium stress on Oryza sativa via modulation of the photosynthesis and antioxidant defense system

Cadmium (Cd) is a trace element causing severe toxicity symptoms in plants, besides posing hazardous fitness issue due to its buildup in the human body through food chain. Nanoparticles (NPs) are recently employed as a novel strategy to directly ameliorate the Cd stress and acted as nano-fertilizers. The intend of the current study was to explore the effects of zinc oxide nanoparticles (ZnO-NPs; 50 mg/L) on plant growth, photosynthetic activity, elemental status and antioxidant activity in Oryza sativa (rice) under Cd (0.8 mM) stress. To this end, the rice plants are treated by Cd stress at 15 days after sowing (DAS), and the treatment was given directly into the soil. Supply of ZnO-NPs as foliar spray was given for five consecutive days from 30 to 35 DAS, and sampling was done at 45 DAS. However, rice plants supplemented with ZnO-NPs under the Cd toxicity revealed significantly increased shoot length (SL; 34.0%), root fresh weight (RFW; 30.0%), shoot dry weight (SDW; 23.07%), and root dry weight (RDW; 12.24%). Moreover, the ZnO-NPs supplement has also positive effects on photosynthesis related parameters, SPAD value (40%), chloroplast structure, and qualitatively high fluorescence observed by confocal microscopy even under Cd stress. ZnO-NPs also substantially prevented the increases of hydrogen peroxide (H2O2) and malondialdehyde (MDA) triggered by Cd. Physiological and biochemical analysis showed that ZnO-NPs increased enzymatic activities of superoxide dismutase (SOD; 59%), catalase (CAT; 52%), and proline (17%) that metabolize reactive oxygen species (ROS); these increases coincided with the changes observed in the H2O2 and MDA accumulation after ZnO-NPs application. In conclusion, ZnO-NPs application to foliage has great efficiency to improve biomass, photosynthesis, protein, antioxidant enzymes activity, mineral nutrient contents and reducing Cd levels in rice. This can be attributed mainly from reduced oxidative damage resulted due to the ZnO-NPs application

Iron Deficiency Modulates Secondary Metabolites Biosynthesis and Antioxidant Potential in <i>Sulla carnosa</i> L. Primed with Salicylic Acid

Iron (Fe) is a vital nutrient for the development of many plants. Therefore, enhancing plant performance and production in relation to Fe deficiency is becoming a serious challenge. In this work, we intended to survey the effect of seed pretreatment with salicylic acid (SA) on oxidative status, phenolic composition, and related antioxidant activities in two varieties of Sulla carnosa (Sidi Khlif: SK and Kalbia: KA) treated with different Fe concentrations. In unprimed plants, the levels of phenolic compounds were very distinguishable among the two varieties, being superior in KA compared to SK. Interestingly, priming KA seeds with SA under control conditions or deficient conditions (D+SA treatment) caused a decreasing tendency in the contents of total phenolic compounds (TPC) and total flavonoids (TFC), whereas an opposite behavior was observed in SK. Moreover, an improvement of hydroxycinnamic and flavonoid groups, in addition to antioxidant activities (TAC, DPPH●, β-carotene and FRAP), was markedly found in SK primed with SA. According to these findings, SA seed pretreatment had a beneficial effect on the metabolic performance of this species under different Fe supply, regardless of whether the intensity of improvement was related to Fe concentration applied, variety, as well as plant organ. The results suggest that SA can account for the effective modulation of the secondary metabolites metabolism in S. carnosa plants to deal with the detrimental impacts of Fe deficiency

Cross-Priming Approach Induced Beneficial Metabolic Adjustments and Repair Processes during Subsequent Drought in Olive

Cross-tolerance to abiotic stresses is a typical phenomenon in plants which occurs when exposure to one form of stress confers tolerance to a variety of stresses. Our study aims at investigating whether salinity priming could induce, after a recovery period (2 months), drought tolerance in olive cv. Ch&eacute;toui. Here, our results revealed that this method of cross-adaptation had further enhanced the olive&rsquo;s subsequent response to drought. In fact, relative to the non-pretreated plants, the salt-pretreated ones displayed an enhancement in terms of shoot biomass accumulation, photosynthetic performance, water-use efficiency, and hydration status. Furthermore, the attenuation of oxidative stress and the maintenance of structural lipid contents, as well as their fatty acid composition in salt-pretreated plants, also supported the beneficial effect of this method. From our results, it seems that salt priming substantially modulated the physiological and biochemical responses of olive plants to subsequent drought. Accordingly, metabolite adjustments (soluble sugars and proline), the enzymatic antioxidant system (superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GP) activities) as well as the nonenzymatic one (phenols), and the increase in leaf density together with the raise of structural lipids content, to a lesser extent, seemed to perform a major role in the development of this improved tolerance to drought. The ameliorative response found in salt-primed olive plants, when subsequently exposed to drought, indicates an efficient cross-tolerance reaction. This could be particularly important in the Mediterranean area, where olive orchards are mainly cultivated under dry-land farming management

Comportement agro-physiologique et biochimique de différents génotypes de féverole (Vicia fava L. var. 'minor') soumis au déficit hydrique

Drought is one of the major abiotic factors affecting growth and productivity of plants by imposing certain morphological, physiological and biochemical changes at different growth stages. The objective of this work is to study key morphological, physiological and biochemical response of faba bean (Vicia faba L. var. 'minor') to soil water deficit stress and to assess the contribution of genetic factors in improving faba bean tolerance to water deficit. Plant of 11 faba bean cultivars were grown in the greenhouse and subjected to three levels of water deficit (90, 50 and 30% of field capacity (FC)) in a simple randomized design for 20 days. Water deficit effects on plant growth, relative water content (RWC), gaz exchange, chlorophyll a (Chla) and Chlorophyll b (Chlb) content, osmoprotectant accumulations (such as proline and soluble sugars), antioxydant enzyme activities and grain yield were determined. Soil water deficit stress reduced growth and affected physiological parameters, especially antioxidant enzyme activities. Water deficit also increased proline, soluble sugars and protein contents. The studied cultivars significantly differed in their responses to water deficit stress. Photosynthetic parameters were less affected in the 'Hara' cultivar. Furthermore, this cultivar produced the highest value of grain yield at 30% FC, and showed higher antioxidant enzyme activities (CAT, GPX and APX), osmoprotectant accumulations, Chlb and RWC. The 'Hara' cultivar was found to be more tolerant to water deficit stress than the other cultivars. Our methodology can be used for assessing the response of faba bean genetic resources to soil water deficit. The identified tolerant cultivar can be utilized as a source for water stress tolerance in faba bean breeding programs aimed at improving drought tolerance

Ginger Extract and Fulvic Acid Foliar Applications as Novel Practical Approaches to Improve the Growth and Productivity of Damask Rose

Plant biostimulants (BIOs) have been identified as among the best agricultural practices over the past few decades. Ginger extract (GE) and fulvic acid (FA) are a new family of multifunctional BIOs that positively affect development processes in plants. However, the underlying mechanisms that influence these development processes are still unknown. The objective of this study was to determine how GE and FA affect the plant growth and productivity in damask rose. Furthermore, the mechanisms of these BIOs that regulate the performance of this plant were investigated. Damask rose plants were foliar-sprayed with GE (5, 10 and 15 mg L&minus;1) or FA (1, 3 and 5 g L&minus;1), while control plants were sprayed with tap water. The results showed that GE or FA foliar applications enhanced plant height and branch number much more than the control; however, FA treatment was more effective than GE. Intriguingly, flower number, flower yield, relative water content, and total chlorophyll content were all improved by either GE or FA, paying attention to reducing the blind shoot number per plant. Relative to the control, foliar application with 15 mg L&minus;1 GE or 3 mg L&minus;1FA increased the flower number by 16.11% and 19.83% and the flower yield per hectare by 40.53% and 52.75%, respectively. Substantial enhancements in volatile oil content and oil yield were observed due to GE and FA treatments, especially with the highest concentrations of both BIOs. The treatments of GE and FA considerably improved the total soluble sugars, total phenolic content, total anthocyanin content, and total carotenoid content, more so with FA. Additionally, the contents of N, P, K, Mg, Fe, and Zn elements were also enhanced by applying either GE or FA, especially at higher levels of both BIOs. In sum, our findings illuminate the potential functions of exogenous application of GE and FA in improving the growth, flower yield, and volatile oil yield in damask rose through enhancing the phytochemical and nutrient profiles. Applications of GE and FA can, thus, be a promising approach for enhancing the productivity of damask rose