112 research outputs found
Mulberry based zinc nano-particles mitigate salinity induced toxic effects and improve the grain yield and zinc bio-fortification of wheat by improving antioxidant activities, photosynthetic performance, and accumulation of osmolytes and hormones
Salinity stress (SS) is a challenging abiotic stress that limits crop growth and productivity. Sustainable and cost effective methods are needed to improve crop production and decrease the deleterious impacts of SS. Zinc (Zn) nanoparticles (NPs) have emerged as an important approach to regulating plant tolerance against SS. However, the mechanisms of SS tolerance mediated by Zn-NPs are not fully explained. Thus, this study was performed to explore the role of Zn-NPs (seed priming and foliar spray) in reducing the deleterious impacts of SS on wheat plants. The study comprised different SS levels: control, 6 and 12 dS m−1, and different Zn-NPs treatments: control, seed priming (40 ppm), foliar spray (20 ppm), and their combination. Salinity stress markedly reduced plant growth, biomass, and grain yield. This was associated with enhanced electrolyte leakage (EL), malondialdehyde (MDA),
hydrogen peroxide (H2O2), sodium (Na), chloride (Cl) accumulation, reduced photosynthetic pigments, relative water contents (RWC), photosyntetic rate (Pn), transpiration rate (Tr), stomata conductance (Gs), water use efficiency (WUE), free amino acids (FAA), total soluble protein (TSP), indole acetic acid (IAA), gibberellic acid (GA), and nutrients (Ca, Mg, K, N, and P). However, the application of Zn-NPs significantly improved the yield of the wheat crop, which was associated with reduced abscisic acid (ABA), MDA, H2O2 concentration, and EL, owing to improved antioxidant activities, and an increase in RWC, Pn, Tr, WUE, and the accumulation of osmoregulating compounds (proline, soluble sugars, TSP, and FAA) and hormones (GA and IAA). Furthermore, Zn-NPs contrasted the salinity-induced uptake of toxic ions (Na and Cl) and increased the uptake of Ca, K, Mg, N, and P. Additionally, Zn-NPs application substantially increased the wheat grain Zn bio-fortification. Our results support previous findings on the role of Zn-NPs in wheat growth, yield, and grain Zn bio-fortification, demonstrating that beneficial effects are obtained under normal as well as adverse conditions, thanks to improved physiological activity and the accumulation of useful compounds. This sets the premise for general use of Zn-NPs in wheat, to which aim more experimental evidence is intensively being sought. Further studies are needed at the genomic, transcriptomic, proteomic, and metabolomic level to better acknowledge the mechanisms of general physiological enhancement observed with Zn-NPs application
Hydrogen sulphide and nitric oxide mitigate the negative impacts of waterlogging stress on wheat (Triticum aestivum L.)
Nitric oxide (NO) and hydrogen sulphide (H2S) are important gaseous signalling molecules that regulate key physiochemical mechanisms of plants under environmental stresses. A number of attempts have been made to improve waterlogging tolerance in plants, but with limited success. Having said that, NO and H2S are vital signalling molecules, but their role in mitigating waterlogging effects on crop plants is not well established. We investigated the efficacy of exogenous NO and H2S to alleviate waterlogging effects in two wheat cultivars (Galaxy-2013 and FSD-2008). Waterlogging produced a noticeable reduction in plant growth, yield, chlorophyll, soluble sugars and free amino acids. Besides, waterlogging induced severe oxidative damage seen as higher cellular TBARS and H2O2 content. Antioxidant enzyme activity increased together with a notable rise in Fe2+ and Mn2+ content. Proline content was higher in waterlogged plants compared with non-waterlogged plants. In contrast, waterlogging caused a substantial decline in endogenous levels of essential nutrients (K+, Ca2+ and Mg2+). Waterlogged conditions led to Fe2+ and Mn2+ toxicity due to rapid reduction of Fe3+ and Mn3+ in the soil. Exogenous NO and H2S significantly protected plants from waterlogging effects by enhancing the oxidative defence and regulating nutritional status. Besides, the protective effects of exogenous NO were more prominent as compared with effects of H2S. Further, we did not study the effect of H2S and NO on photosynthetic attributes and expression of stress-related genes. Therefore, future studies should examine the effects of H2S and NO on wheat physiology and gene expression under waterlogging
Improved salinity tolerance in early growth stage of maize through salicylic acid foliar application
Soil salinity threatens agricultural production worldwide by constraining plant growth and final crop yield. The early stages are most sensitive to salinity, in response to which salicylic acid (SA) has demonstrated beneficial effects in various plant species. Based on this, a maize (Zea mays L.) pot experiment was set up combining three levels of soil salinity (0, 6 and 12 dS m–1), obtained through NaCl addition, with three levels of SA (0, 300 and 600 mM), applied by leaf spraying 20 days after seedling emergence. Fifteen days later, the following traits were assessed: morphology (plant height, leaf number), growth (root and shoot dry weight), leaf water status [relative water content (RWC), elec-trolyte leakage (EL)], pigments (chlorophyll a and b, carotenoids, anthocyanin), antioxidant enzymes (peroxidase, catalase, ascor-bate peroxidase, vitamin C), oxidative stress markers (H2O2, mal-ondialdehyde), osmo-regulating compounds (free amino acids, soluble proteins and sugars, proline), hormones [indole-3-acetic acid, gibberellic acid (GA), abscisic acid (ABA), ethylene], ele-ment (Na, K, Ca, Mg and Cl) concentration and content in roots, stem and leaves. Salinity severely affected maize growth (–26% total dry weight), impaired leaf water status (–31% RWC), reduced photosynthetic pigments, enhanced all antioxidant enzymes and oxidative stress markers, two osmo-regulating compounds (soluble sugars and proline) out of four, and all hormones except GA. SA was shown effective in containing most of the stress effects, while supporting plant defences by upgrading anti-oxidant activities (reduced oxidative stress markers), increasing cell membrane stability (–24% EL) and leaf water status (+20% RWC), and reducing plant stress signalling (–10% ABA and –20% ethylene). Above all, SA contrasted the massive entry of noxious ions (Na+ and Cl–), in favour of K+, Ca2+ and Mg2+ accumulation. Lastly, salicylic acid was shown beneficial for maize growth and physiology also under non-saline condition, suggesting a potential use in normal field conditions
Foliar applied zinc on different growth stages to improves the growth, yield, quality and kernel bio-fortification of fine rice
Zinc (Zn) is an essential needed for the growth and development of plants, however, Zn is continuously increasing in our soils which is decreasing crop production. Further, the crops grown on Zn-deficient soils also contains a low amount of Zn which is also a major reason for Zn deficiency in humans. So, it is mandatory to supply the Zn to fulfil the crop needs with a corresponding increase in grain Zn. Therefore, the present study was performed to determine the impact of different rates of foliar applied Zn at different growth stages on the growth, yield, quality, and Zn bio-fortification of fine rice. The study comprised foliar application of distilled water (control), foliar applied Zn @ 0.5% at stem elongation stage + booting stage, foliar applied Zn @ 1.0% at stem elongation stage + booting stage, foliar applied Zn @ 0.5% at booting stage and milking stage, foliar applied Zn @ 1.0% at booting stage and milking stage, foliar applied Zn @ 0.5% at milking stage + dough stage and applied Zn @ 1.0% at milking stage + dough stage. The results indicated Zn applied different growth stages significantly improved, productivity and Zn bio-fortification of rice crop. The maximum LAI, LAD, CGR, fertile tillers, 1000 KW, kernel yield, biomass yield, HI, chlorophyll concentration, relative water content (RWC), and antioxidant activities were observed with foliar applied Zn (0.5%) at booting and milking stage and lowest values of all these traits were observed in control. Likewise, the maximum kernel protein, amylose, kernel length and width, and grain Zn concentration was Zn (0.5%) at the booting and milking stage, and minimum kernel protein, amylose, kernel length, and width, and grain Zn concentration was noted in control. The current study findings suggested that foliar-applied Zn (0.5%) at the booting and milking stage could be an important practice to get better productivity, quality, and grain Zn bio-fortification of rice in semi-arid conditions
Nurses' experiences, expectations, and preferences for mind-body practices to reduce stress
BACKGROUND: Most research on the impact of mind-body training does not ask about participants\u27 baseline experience, expectations, or preferences for training. To better plan participant-centered mind-body intervention trials for nurses to reduce occupational stress, such descriptive information would be valuable.
METHODS: We conducted an anonymous email survey between April and June, 2010 of North American nurses interested in mind-body training to reduce stress. The e-survey included: demographic characteristics, health conditions and stress levels; experiences with mind-body practices; expected health benefits; training preferences; and willingness to participate in future randomized controlled trials.
RESULTS: Of the 342 respondents, 96% were women and 92% were Caucasian. Most (73%) reported one or more health conditions, notably anxiety (49%); back pain (41%); GI problems such as irritable bowel syndrome (34%); or depression (33%). Their median occupational stress level was 4 (0 = none; 5 = extreme stress). Nearly all (99%) reported already using one or more mind-body practices to reduce stress: intercessory prayer (86%), breath-focused meditation (49%), healing or therapeutic touch (39%), yoga/tai chi/qi gong (34%), or mindfulness-based meditation (18%). The greatest expected benefits were for greater spiritual well-being (56%); serenity, calm, or inner peace (54%); better mood (51%); more compassion (50%); or better sleep (42%). Most (65%) wanted additional training; convenience (74% essential or very important), was more important than the program\u27s reputation (49%) or scientific evidence about effectiveness (32%) in program selection. Most (65%) were willing to participate in a randomized trial of mind-body training; among these, most were willing to collect salivary cortisol (60%), or serum biomarkers (53%) to assess the impact of training.
CONCLUSIONS: Most nurses interested in mind-body training already engage in such practices. They have greater expectations about spiritual and emotional than physical benefits, but are willing to participate in studies and to collect biomarker data. Recruitment may depend more on convenience than a program\u27s scientific basis or reputation. Knowledge of participants\u27 baseline experiences, expectations, and preferences helps inform future training and research on mind-body approaches to reduce stress
Evaluation of the efficacy of a commercial inactivated genogroup 2b based porcine epidemic diarrhea virus (PEDV) vaccine and experimental live genogroup 1b exposure against 2b challenge
Abstract Porcine epidemic diarrhea virus strains from the G1b cluster are considered less pathogenic compared to the G2b cluster. The aim of this study was to compare the ability of G1b-based live virus exposure against use of a commercial G2b–based inactivated vaccine to protect growing pigs against G2b challenge. Thirty-nine PEDV naïve pigs were randomly divided into five groups: EXP-IM-1b (intramuscular G1b exposure; G2b challenge), EXP-ORAL-1b (oral G1b exposure; G2b challenge), VAC-IM-2b (intramuscular commercial inactivated G2b vaccination; G2b challenge), POS-CONTROL (sham-vaccination; G2b challenge) and NEG-CONTROL (sham-vaccination; sham-challenge). Pigs were vaccinated/exposed at 3 weeks of age (day post-vaccination 0, dpv 0), VAC-IM-2b pigs were revaccinated at dpv 14, and the pigs were challenged at dpv 28. Among all groups, VAC-IM-2b pigs had significantly higher anti-PEDV IgG levels on dpv 21 and 28 while EXP-ORAL-1b pigs had significantly higher anti-PEDV IgA levels on dpv 14, 21, 28 and 35. EXP-ORAL-1b also had detectable IgA in feces. Intramuscular PEDV exposure did not result in a detectable antibody response in EXP-IM-1b pigs. The fecal PEDV RNA levels in VAC-IM-2b pigs were significantly lower 5–7 days after challenge compared to the POS-CONTROL group. Under the study conditions a commercial inactivated G2b-based vaccine protected pigs against G2b challenge, as evidenced by reduction of PEDV RNA in feces for 3–4 logs during peak shedding and a shorter viral shedding duration. The oral, but not the intramuscular, experimental G1b-based live virus exposure induced a high anti-PEDV IgA response prior to challenge, which apparently did not impact PEDV shedding compared to POS-CONTROL pigs
The AgMIP Coordinated Climate-Crop Modeling Project (C3MP): Methods and Protocols
Climate change is expected to alter a multitude of factors important to agricultural
systems, including pests, diseases, weeds, extreme climate events, water resources,
soil degradation, and socio-economic pressures. Changes to carbon dioxide concentration
([CO2]), temperature, andwater (CTW) will be the primary drivers of change
in crop growth and agricultural systems. Therefore, establishing the CTW-change
sensitivity of crop yields is an urgent research need and warrants diverse methods
of investigation. Crop models provide a biophysical, process-based tool to investigate crop
responses across varying environmental conditions and farm management techniques,
and have been applied in climate impact assessment by using a variety of
methods (White et al., 2011, and references therein). However, there is a significant
amount of divergence between various crop models’ responses to CTW changes
(R¨otter et al., 2011). While the application of a site-based crop model is relatively
simple, the coordination of such agricultural impact assessments on larger scales
requires consistent and timely contributions from a large number of crop modelers,
each time a new global climate model (GCM) scenario or downscaling technique
is created. A coordinated, global effort to rapidly examine CTW sensitivity across
multiple crops, crop models, and sites is needed to aid model development and
enhance the assessment of climate impacts (Deser et al., 2012)..
Efficacy, safety and effectiveness of licensed rotavirus vaccines: a systematic review and meta-analysis for Latin America and the Caribbean
Effects of fluoxetine on functional outcomes after acute stroke (FOCUS): a pragmatic, double-blind, randomised, controlled trial
Background
Results of small trials indicate that fluoxetine might improve functional outcomes after stroke. The FOCUS trial aimed to provide a precise estimate of these effects.
Methods
FOCUS was a pragmatic, multicentre, parallel group, double-blind, randomised, placebo-controlled trial done at 103 hospitals in the UK. Patients were eligible if they were aged 18 years or older, had a clinical stroke diagnosis, were enrolled and randomly assigned between 2 days and 15 days after onset, and had focal neurological deficits. Patients were randomly allocated fluoxetine 20 mg or matching placebo orally once daily for 6 months via a web-based system by use of a minimisation algorithm. The primary outcome was functional status, measured with the modified Rankin Scale (mRS), at 6 months. Patients, carers, health-care staff, and the trial team were masked to treatment allocation. Functional status was assessed at 6 months and 12 months after randomisation. Patients were analysed according to their treatment allocation. This trial is registered with the ISRCTN registry, number ISRCTN83290762.
Findings
Between Sept 10, 2012, and March 31, 2017, 3127 patients were recruited. 1564 patients were allocated fluoxetine and 1563 allocated placebo. mRS data at 6 months were available for 1553 (99·3%) patients in each treatment group. The distribution across mRS categories at 6 months was similar in the fluoxetine and placebo groups (common odds ratio adjusted for minimisation variables 0·951 [95% CI 0·839–1·079]; p=0·439). Patients allocated fluoxetine were less likely than those allocated placebo to develop new depression by 6 months (210 [13·43%] patients vs 269 [17·21%]; difference 3·78% [95% CI 1·26–6·30]; p=0·0033), but they had more bone fractures (45 [2·88%] vs 23 [1·47%]; difference 1·41% [95% CI 0·38–2·43]; p=0·0070). There were no significant differences in any other event at 6 or 12 months.
Interpretation
Fluoxetine 20 mg given daily for 6 months after acute stroke does not seem to improve functional outcomes. Although the treatment reduced the occurrence of depression, it increased the frequency of bone fractures. These results do not support the routine use of fluoxetine either for the prevention of post-stroke depression or to promote recovery of function.
Funding
UK Stroke Association and NIHR Health Technology Assessment Programme
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