scholarly journals Effect of Different Forms of Selenium on the Physiological Response and the Cadmium Uptake by Rice under Cadmium Stress

2020 ◽  
Vol 17 (19) ◽  
pp. 6991
Author(s):  
Haizhao Xu ◽  
Jinpeng Yan ◽  
Yan Qin ◽  
Jingmao Xu ◽  
M. J. I. Shohag ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Subcellular Distribution ◽  
Biomass Accumulation ◽  
Cadmium Stress ◽  
Antioxidant Defense System ◽  
Chemical Forms ◽  
Rice Seedlings ◽  
Potential Threat ◽  
Cd Translocation ◽  
The Impact

Cadmium (Cd) is a pollutant toxic to plants and a potential threat to human health. Selenium (Se), though not essential for plants, has beneficial effects on plants under abiotic stress. A hydroponic experiment was conducted to investigate the impact of different forms of Se (Nano-Se, selenite, selenate, and SeMet) on accumulation, subcellular distribution, and chemical forms of Cd, as well as oxidative stress in rice seedlings. Cd (20 μmol·L−1) treatment significantly decreased biomass accumulation and chlorophyll content. The application of all Se forms, except selenate, mitigated the adverse effects of Cd on growth and chlorophyll content. The application of selenite, Nano-Se, and SeMet decreased root and shoot Cd concentrations as well as root-to-shoot Cd translocation in rice seedlings. Selenate application decreased shoot Cd concentration and root-to-shoot Cd translocation with no effect on root Cd concentration. Accordingly, Se increased the sequestration of Cd in the cell wall and vacuoles and decreased the active chemical form of Cd in rice seedlings. SeMet was the most effective supplement that decreased Cd concentration and enhanced Se concentration in the roots and shoots of rice seedlings. All forms of Se further enhanced catalase (CAT) and glutathione peroxidase (GSH-Px) activities and inhibited MDA accumulation. To conclude, Se influenced Cd accumulation and translocation in rice seedlings by altering the subcellular distribution, chemical forms, and antioxidant defense system under Cd stress. These effects were highly significant with SeMet treatment, probably due to better absorption and utilization by the plant.

scholarly journals Exogenous melatonin alleviates cadmium uptake and toxicity in apple rootstocks

2020 ◽  
Vol 40 (6) ◽  
pp. 746-761 ◽  
Author(s):  
Jiali He ◽  
Xiaolei Zhuang ◽  
Jiangtao Zhou ◽  
Luyang Sun ◽  
Huixue Wan ◽  
...  
Keyword(s):  
Cadmium Stress ◽  
Antioxidant Defense System ◽  
Mrna Levels ◽  
Apple Rootstocks ◽  
Melatonin Treatment ◽  
Cd Uptake ◽  
Cd Accumulation ◽  
Exogenous Melatonin ◽  
Malus Baccata ◽  
Cd Translocation

Abstract To examine the potential roles of melatonin in cadmium (Cd) uptake, accumulation and detoxification in Malus plants, we exposed two different apple rootstocks varying greatly in Cd uptake and accumulation to either 0 or 30 μM Cd together with 0 or 100 μM melatonin. Cadmium stress stimulated endogenous melatonin production to a greater extent in the Cd-tolerant Malus baccata Borkh. than in the Cd-susceptible Malus micromalus ‘qingzhoulinqin’. Melatonin application attenuated Cd-induced reductions in growth, photosynthesis and enzyme activity, as well as reactive oxygen species (ROS) and malondialdehyde accumulation. Melatonin treatment more effectively restored photosynthesis, photosynthetic pigments and biomass in Cd-challenged M. micromalus ‘qingzhoulinqin’ than in Cd-stressed M. baccata. Exogenous melatonin lowered root Cd2+ uptake, reduced leaf Cd accumulation, decreased Cd translocation factors and increased root, stem and leaf melatonin contents in both Cd-exposed rootstocks. Melatonin application increased both antioxidant concentrations and enzyme activities to scavenge Cd-induced ROS. Exogenous melatonin treatment altered the mRNA levels of several genes regulating Cd uptake, transport and detoxification including HA7, NRAMP1, NRAMP3, HMA4, PCR2, NAS1, MT2, ABCC1 and MHX. Taken together, these results suggest that exogenous melatonin reduced aerial parts Cd accumulation and mitigated Cd toxicity in Malus plants, probably due to the melatonin-mediated Cd allocation in tissues, and induction of antioxidant defense system and transcriptionally regulated key genes involved in detoxification.

scholarly journals Interactive effect of potassium and cadmium on growth, root morphology and chlorophyll a fluorescence in tomato plant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachida Naciri ◽  
Meryeme Lahrir ◽  
Chahinez Benadis ◽  
Mohamed Chtouki ◽  
Abdallah Oukarroum
Keyword(s):  
Plant Growth ◽  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Root Morphology ◽  
Chlorophyll A Fluorescence ◽  
Tomato Plant ◽  
Cd Stress ◽  
Negative Effect ◽  
Cd Translocation ◽  
The Impact

AbstractA hydroponic experiment was conducted to evaluate the role of potassium (K) in tomato plant growth exposed to cadmium (Cd) stress. In this work, the effects of three potassium nutrition regimes (155, 232 and 310 ppm of K) combined with Cd at different levels (0, 12 and 25 µM of CdCl2) on chlorophyll content index, root and shoot dry weights, root morphology, chlorophyll a fluorescence and translocation factor were analyzed. The results showed a negative effect of cadmium, at different concentrations, on all these parameters. However, optimization of K nutrition has shown promising results by limiting the negative effect of Cd. A positive effect of the high concentration of K (310 ppm) was observed on leaf chlorophyll content and chlorophyll a fluorescence compared to 232 and 155 ppm under Cd stress. K supply improved the electron transport at PSI side indicated by the increase in the amplitude of the I–P phase of OJIP transient. Also, K at a concentration of 310 ppm significantly reduced Cd translocation from root to shoot and improved root and shoot growth parameters in the presence of Cd. K supplementation can reduce the negative effect of Cd by improving photosynthesis and promoting chlorophyll synthesis. The optimization of nutrients composition and concentration might be a good strategy to reduce the impact of Cd on plant growth and physiology.

Effects of exogenous spermidine on subcellular distribution and chemical forms of cadmium in Typha latifolia L. under cadmium stress

2009 ◽  
Vol 59 (8) ◽  
pp. 1487-1493 ◽  
Author(s):  
C. F. Tang ◽  
R. Q. Zhang ◽  
S. Z. Wen ◽  
C. F. Li ◽  
X. F. Guo ◽  
...  
Keyword(s):  
Subcellular Distribution ◽  
Cell Walls ◽  
Metal Ion ◽  
Chemical Speciation ◽  
Typha Latifolia ◽  
Cadmium Stress ◽  
Chemical Forms ◽  
Hydroponic System ◽  
Metal Metal ◽  
Exogenous Spermidine

The effects of foliar spraying with spermidine (Spd) on the subcellular distribution and chemical speciation of Cd in Typha latifolia L. in hydroponic system were investigated. Increased Cd concentration in the medium caused an increase of Cd concentration in all tissues and all subcellular fractions, with the highest Cd level occurring in roots, followed by rhizomes and leaves and the greatest accumulation was in cell walls, soluble fraction and organelle containing fractions ranked next, respectively. The greatest amount of Cd was found in the extraction of 1 mol·L−1 NaCl, followed by 2% HAC, deionized water, 80% ethanol, residues and the least in 0.6 mol·L−1 HCl. The subcellular distribution and different chemical forms of Cd both decreased after Spd application and were more inhibited by 0.25 than 0.50 mmol·L−1 Spd, especially in roots at 0.10 mmol·L−1 Cd treatment. It could be suggested that the retention of Cd in roots, cell walls binding with metal, metal ion compartmentation in vacuoles and Cd forms existing in undissolved and integrated with pectates and protein play an important role in Cd detoxification and Spd could enhance the tolerance of cattail to Cd stress.

scholarly journals Potassium Application Positively Modulates Physiological Responses of Cocoa Seedlings to Drought Stress

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 563
Author(s):  
Esther Anokye ◽  
Samuel T. Lowor ◽  
Jerome A. Dogbatse ◽  
Francis K. Padi
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Chlorophyll Content ◽  
Electrolyte Leakage ◽  
Seedling Survival ◽  
Biomass Accumulation ◽  
Biomass Partitioning ◽  
Chlorophyll Content And Fluorescence ◽  
Physiological Functions ◽  
Soil Water Stress

With increasing frequency and intensity of dry spells in the cocoa production zones of West Africa, strategies for mitigating impact of water stress on cocoa seedling survival are urgently required. We investigated the effects of applied potassium on biomass accumulation, physiological processes and survival of cocoa varieties subjected to water stress in pot experiments in a gauzehouse facility. Four levels of potassium (0, 1, 2, or 3 g/plant as muriate of potash) were used. Soil water stress reduced plant biomass accumulation (shoot and roots), relative water content (RWC), chlorophyll content and fluorescence. Leaf phenol and proline contents were increased under water stress. Additionally, compared to the well-watered conditions, soils under water stress treatments had higher contents of exchangeable potassium and available phosphorus at the end of the experimental period. Potassium applied under well-watered conditions reduced leaf chlorophyll content and fluorescence and increased leaf electrolyte leakage, but improved the growth and integrity of physiological functions under soil water stress. Potassium addition increased biomass partitioning to roots, improved RWC and leaf membrane stability, and significantly improved cocoa seedling survival under water stress. Under water stress, the variety with the highest seedling mortality accumulated the highest contents of phenol and proline. A significant effect of variety on plant physiological functions was observed. Generally, varieties with PA 7 parentage had higher biomass partitioning to roots and better seedling survival under soil moisture stress. Proportion of biomass partitioned to roots, RWC, chlorophyll fluorescence and leaf electrolyte leakage appear to be the most reliable indicators of cocoa seedling tolerance to drought.

scholarly journals Self-Secondaries Formed by Cold Spot Craters on the Moon

2021 ◽  
Vol 13 (6) ◽  
pp. 1087
Author(s):  
Yiren Chang ◽  
Zhiyong Xiao ◽  
Yang Liu ◽  
Jun Cui
Keyword(s):  
Systematic Investigation ◽  
Impact Craters ◽  
Spatial Density ◽  
Cold Spot ◽  
The Moon ◽  
Potential Threat ◽  
Frequency Distributions ◽  
Crater Size ◽  
The Impact ◽  
Density Pattern

Self-secondaries are a population of background secondaries, and they have been observed on top of impact melt and ballistically emplaced ejecta deposits on various planetary bodies. Self-secondaries are formed by impacts of sub-vertically launched ejecta, but the launch mechanism is not confirmed. The potential threat of self-secondaries to the theoretical and applicable reliability of crater chronology has been noted, but not constrained. Hitherto discovered self-secondaries were located around complex impact craters, but their potential existence around simple craters has not been discovered. Here we report the first discovery of self-secondaries around lunar cold spot craters, which are an extremely young population of simple craters formed within the past ~1 million years on the Moon. Self-secondaries are widespread on layers of cascading flow-like ejecta deposits around cold spot craters. The spatial density of self-secondaries dwarfs that of potential primary craters. The spatial distribution of self-secondaries is highly heterogeneous across the ejecta deposits. With respect to the impactor trajectory that formed cold spot craters, self-secondaries formed at the downrange of the ejecta deposits have the largest spatial density, while those at the uprange have the smallest density. This density pattern holds for all cold spot craters that were formed by non-vertical impacts, but self-secondaries do not exhibit other systematic density variations at different radial distances or at other azimuths with respect to the impactor trajectory. Among known mechanics of ejecting materials to the exterior of impact craters, impact spallation is the most likely scenario to account for the required large ejection velocities and angles to form self-secondaries. The production population of self-secondaries is estimated based on the highly diverse crater size-frequency distributions across the ejecta deposits of cold spot craters. For a better understanding of the impact history on the Moon, a systematic investigation for the effect of self-secondaries on lunar crater chronology is required.

scholarly journals Do Microplastics Enter Our Food Chain Via Root Vegetables? A Raman Based Spectroscopic Study on Raphanus sativus

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2329
Author(s):  
Leda-Eleni Tympa ◽  
Klytaimnistra Katsara ◽  
Panagiotis N. Moschou ◽  
George Kenanakis ◽  
Vassilis M. Papadakis
Keyword(s):  
Raphanus Sativus ◽  
Acrylonitrile Butadiene Styrene ◽  
Terrestrial Ecosystems ◽  
Label Free ◽  
Plastic Pollution ◽  
Potential Threat ◽  
Safety Studies ◽  
Widespread Phenomenon ◽  
Agriculture And Food ◽  
The Impact

The outburst of plastic pollution in terrestrial ecosystems poses a potential threat to agriculture and food safety. Studies have already provided evidence for the uptake of plastic microparticles by several plant species, accompanied by numerous developmental effects, using fluorescence labelling techniques. Here, we introduce the implementation of confocal Raman spectroscopy, a label-free method, for the effective detection of microplastics (MPs) accumulation in the roots of a common edible root vegetable plant, Raphanus sativus, after treatment with acrylonitrile butadiene styrene (ABS) powder. We also demonstrate the concomitant occurrence of phenotypic defects in the polymer-treated plants. We anticipate that this work can provide new insights not only into the extent of the impact this widespread phenomenon has on crop plants but also on the methodological requirements to address it.

The Journalist—Source Relationship in Context: A Comparative Review of US and English Law

2009 ◽  
Vol 38 (3) ◽  
pp. 268-294
Author(s):  
Stuart Wallace
Keyword(s):  
Human Rights ◽  
Legal Protection ◽  
State Level ◽  
Potential Threat ◽  
Shield Law ◽  
Special Procedure ◽  
European Court ◽  
Comparative Review ◽  
The Uk ◽  
The Impact

This paper analyses the legal protection of the journalist–source relationship from both sides and the underlying interests involved. The paper begins by analysing why the relationship deserves protection. The position of journalists at common law is analysed with a discussion of the application of the principle established in Norwich Pharmacal v Customs and Excise to journalists. The development of immunity from contempt in s. 10 of the Contempt of Court Act 1981 is examined to illustrate the ideological clash between the judiciary and journalists. The impact of the Human Rights Act and decisions of the European Court of Human Rights are analysed to assess whether this will lead to a change in attitudes in the UK. Finally, the potential threat to journalists posed by compelled evidentiary disclosure in criminal cases is reviewed, with a particular look at ‘special procedure’ material. The US section begins with an analysis of the law at federal level, the decisions of the Supreme Court, including the leading decision of Branzburg v Hayes, as well as the role the legislature has played. The paper then analyses protections provided at state level, with a case study of the California shield law and a review of Californian jurisprudence.

scholarly journals Impacts of Microcystins on Morphological and Physiological Parameters of Agricultural Plants: A Review

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 639
Author(s):  
Alexandre Campos ◽  
El Mahdi Redouane ◽  
Marisa Freitas ◽  
Samuel Amaral ◽  
Tomé Azevedo ◽  
...  
Keyword(s):  
Drinking Water ◽  
Human Health ◽  
Economic Loss ◽  
Crop Productivity ◽  
Physiological Parameters ◽  
World Health ◽  
Potential Threat ◽  
Regulatory Limits ◽  
Agricultural Plants ◽  
The Impact

Cyanobacteria are a group of photosynthetic prokaryotes that pose a great concern in the aquatic environments related to contamination and poisoning of wild life and humans. Some species of cyanobacteria produce potent toxins such as microcystins (MCs), which are extremely aggressive to several organisms, including animals and humans. In order to protect human health and prevent human exposure to this type of organisms and toxins, regulatory limits for MCs in drinking water have been established in most countries. In this regard, the World Health Organization (WHO) proposed 1 µg MCs /L as the highest acceptable concentration in drinking water. However, regulatory limits were not defined in waters used in other applications/activities, constituting a potential threat to the environment and to human health. Indeed, water contaminated with MCs or other cyanotoxins is recurrently used in agriculture and for crop and food production. Several deleterious effects of MCs including a decrease in growth, tissue necrosis, inhibition of photosynthesis and metabolic changes have been reported in plants leading to the impairment of crop productivity and economic loss. Studies have also revealed significant accumulation of MCs in edible tissues and plant organs, which raise concerns related to food safety. This work aims to systematize and analyze the information generated by previous scientific studies, namely on the phytotoxicity and the impact of MCs especially on growth, photosynthesis and productivity of agricultural plants. Morphological and physiological parameters of agronomic interest are overviewed in detail in this work, with the aim to evaluate the putative impact of MCs under field conditions. Finally, concentration-dependent effects are highlighted, as these can assist in future guidelines for irrigation waters and establish regulatory limits for MCs.

Sign in / Sign up

Export Citation Format

Share Document