scholarly journals Nickel Toxicity Targets Cell Wall-Related Processes and PIN2-Mediated Auxin Transport to Inhibit Root Elongation and Gravitropic Responses in Arabidopsis

2019 ◽  
Vol 61 (3) ◽  
pp. 519-535 ◽  
Author(s):  
Alexandra Leškov� ◽  
Milan Zvar�k ◽  
Takao Araya ◽  
Ricardo F H Giehl
Keyword(s):  
Heavy Metal ◽  
Root Growth ◽  
Fossil Fuels ◽  
Environmental Concern ◽  
Plant Cell Walls ◽  
Nickel Toxicity ◽  
Auxin Distribution ◽  
Leaf Chlorosis ◽  
Transcriptional Changes ◽  
Cell Niche

Abstract Contamination of soils with heavy metals, such as nickel (Ni), is a major environmental concern due to increasing pollution from industrial activities, burning of fossil fuels, incorrect disposal of sewage sludge, excessive manure application and the use of fertilizers and pesticides in agriculture. Excess Ni induces leaf chlorosis and inhibits plant growth, but the mechanisms underlying growth inhibition remain largely unknown. A detailed analysis of root development in Arabidopsis thaliana in the presence of Ni revealed that this heavy metal induces gravitropic defects and locally inhibits root growth by suppressing cell elongation without significantly disrupting the integrity of the stem cell niche. The analysis of auxin-responsive reporters revealed that excess Ni inhibits shootward auxin distribution. Furthermore, we found that PIN2 is very sensitive to Ni, as the presence of this heavy metal rapidly reduced PIN2 levels in roots. A transcriptome analysis also showed that Ni affects the expression of many genes associated with plant cell walls and that Ni-induced transcriptional changes are largely independent of iron (Fe). In addition, we raised evidence that excess Ni increases the accumulation of reactive oxygen species and disturbs the integrity and orientation of microtubules. Together, our results highlight which processes are primarily targeted by Ni to alter root growth and development.

Microscopic characteristic of biological iron sulfide composites during the generation process and the association with treatment effect on heavy metal wastewater

2014 ◽  
Vol 70 (7) ◽  
pp. 1292-1297 ◽  
Author(s):  
Yang Yang ◽  
Yifei Xie ◽  
Xudong Li ◽  
Jingchao Zhou ◽  
Jingwei Liu
Keyword(s):  
Heavy Metal ◽  
Stationary Phase ◽  
Iron Sulfide ◽  
Treatment Time ◽  
Environmental Concern ◽  
Morphological Changes ◽  
Generation Process ◽  
Toxic Heavy Metals ◽  
Practical Applications ◽  
Heavy Metal Wastewater

Heavy metal pollution is a serious environmental concern worldwide, resulting in both environmental and human harm. Recently, studies have shown that environmental biotechnologies based on sulfate reduction offer a potential for removal of toxic heavy metals. Biological iron sulfide composites are iron sulfide compounds generated in situ by sulfate-reducing bacteria. In this study, microscopic morphological changes during the composites' generation process were studied, and the effect of biological iron sulfide composites in different generation phases on treatment of heavy metal wastewater was investigated to establish the correlation between macro-effect and micro-properties. The results revealed that the generation process of biological iron sulfide composites occurs in three phases: the formation phase, stationary phase, and agglomeration phase. The stationary phase can be divided into a pre-stationary phase and post-stationary phase. It was found that the best treatment time for Cr6+ is in the pre-stationary phase, while the best treatment time for Cu2+and Cd2+ is in the post-stationary phase. The results of this study further prove the benefits of treatment of heavy metal wastewater using biological sulfide composites and provide theoretical guidance in practical applications.

scholarly journals Kestabilan Inokulan Azotobacter selama Penyimpanan pada Dua Suhu

2012 ◽  
Vol 14 (1) ◽  
pp. 52
Author(s):  
Reginawanti Hindersah ◽  
Rija Sudirja
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Root Growth ◽  
Contaminated Soil ◽  
Metal Uptake ◽  
Room Temperature ◽  
Heavy Metal Uptake ◽  
Total N ◽  
The Stability ◽  
Temperature Storage

Azotobacter might be used as biological agents in bioremediation of heavy metal-contaminated soil since this rhizobacteria produceexopolysachharides (EPS) that mobilize soil heavy metals, and phytohormones that regulate root growth. So that heavy metal uptake bythe roots could be increased. The objective of this research was to verify the stability of EPS and phytohormones in Azotobacter liquidinoculants during four months in different temperature storage. Liquid inoculants has been produced in EPS-induced media and stored in200C and room temperature (24-270C) during four months. The results showed that the better temperature storage was room temperatureinstead of 20 0C since pH, total N, and EPS and phytohormones content was relatively stable during storage.

Tolerance of Microorganisms to Heavy Metals

2021 ◽  
pp. 19-35
Author(s):  
Joan Mwihaki Nyika
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Metal Toxicity ◽  
Environmental Concern ◽  
Volume Ratio ◽  
Fungal Species ◽  
Wide Range ◽  
Bioremediation Processes

Heavy metal pollution is a growing environmental concern due to the increase in anthropogenic-based sources. Microorganisms have high adsorptive capacities and surface-area-to-volume ratio that enable the uptake of these contaminants and their conversion to innocuous complexes in the process of bioremediation. This chapter explores the mechanisms and specific microorganisms that are resistant to metal toxicity. A wide range of bacterial, algae, and fungal species used as biosorbents are highlighted. Mechanisms such as reduction of metal cations, their sequestration, and binding on cell barriers are discussed. To optimise the efficacy of microorganisms in bioremediation processes, adoption of genetic and nano-technologies is recommended.

scholarly journals Overexpression of OsPIN2 Regulates Root Growth and Formation in Response to Phosphate Deficiency in Rice

2019 ◽  
Vol 20 (20) ◽  
pp. 5144
Author(s):  
Huwei Sun ◽  
Xiaoli Guo ◽  
Fugui Xu ◽  
Daxia Wu ◽  
Xuhong Zhang ◽  
...  
Keyword(s):  
Root Growth ◽  
Growth And Development ◽  
Plant Root ◽  
Lateral Roots ◽  
Root Hairs ◽  
Phosphate Deficiency ◽  
P Deficiency ◽  
Auxin Distribution ◽  
Seminal Roots ◽  
Underlying Mechanisms

The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.

scholarly journals Production and Postharvest Characteristics of Rosa hybrida L. `Meijikatar' Grown in Pots under Carbon Dioxide Enrichment

1993 ◽  
Vol 118 (5) ◽  
pp. 613-617 ◽  
Author(s):  
David G. Clark ◽  
John W. Kelly ◽  
Nihal C. Rajapakse
Keyword(s):  
Carbon Dioxide ◽  
Root Growth ◽  
Chlorophyll Concentration ◽  
Early Spring ◽  
Rosa Hybrida ◽  
Late Winter ◽  
Carbon Dioxide Enrichment ◽  
Flower Buds ◽  
Flower Bud ◽  
Leaf Chlorosis

The effects of carbon dioxide enrichment on growth, photosynthesis, and postharvest characteristics of `Meijikatar' potted roses were determined. Plants were grown in 350, 700, or 1050 μl CO2/liter until they reached 50% flower bud coloration and then were placed into dark storage for 5 days at 4 or 16C. Plants grown in 700 or 1050 μl CO2/liter reached the harvest stage earlier and were taller at harvest than plants produced in 350 μl CO2/liter, but there were no differences in the number of flowers and flower buds per plant among CO2 treatments. Plants grown in early spring were taller and had more flowers and flower buds than plants grown in late winter. Shoot and root growth of plants grown in 700 or 1050 μl CO2/liter were higher than in plants produced in 350 μl CO2/liter, with plants grown in early spring showing greater increases than plants grown in late winter. Immediately after storage, plants grown in 350 μl CO2/liter and stored at 4C had the fewest etiolated shoots, while plants grown in 1050 μl CO2/liter and stored at 16C had the most. Five days after removal from storage, chlorophyll concentration of upper and lower leaves had been reduced by ≈50% from the day of harvest. Carbon dioxide enrichment had no effect on postharvest leaf chlorosis, but plants grown in early spring and stored at 16C had the most leaf chlorosis while plants grown in late winter and stored at 4C had the least leaf chlorosis.

scholarly journals Use of biomass sorghum for the bioremediation of heavy metal-contaminated environments

2020 ◽  
Vol 9 (9) ◽  
pp. e95996770
Author(s):  
André May ◽  
Evandro Henrique Figueiredo Moura da Silva ◽  
Michelli de Souza dos Santos ◽  
Ronaldo da Silva Viana ◽  
Flávia Cristina dos Santos ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Energy Production ◽  
Fossil Fuels ◽  
High Ability ◽  
Production Potential ◽  
Traditional Methods ◽  
Biomass Sorghum ◽  
Sorghum Plant ◽  
Short Time

Heavy metal-contaminated areas are a recurring problem in a society that increasingly demands fossil fuels, pesticides and fertilizers. Traditional methods to recover these areas are generally very expensive, and phytoremediation can be a solution for their decontamination by removing these contaminants from the soil through the harvest of the plants grown in the affected site, as these elements are extracted from the soil. The harvested part can be used for non-food purposes, such as energy production. In this scenario, the sorghum plant emerges as an alternative owing to its high ability to accumulate biomass in a short time and bioelectricity production potential. This study proposes to examine the use of biomass sorghum for the bioremediation of environments contaminated with the heavy metals Cu and Ni. The experiment was carried out in the municipality of Jaguariúna - SP, Brazil, using four doses of Ni (0, 10.5, 47 and 210 mg kg-1) and Cu (0, 200, 300 and 400 mg kg-1). The sorghum plants exhibited good development even at the highest Cu and Ni doses applied to the soil. The highest levels of Cu and Ni were concentrated in the roots. Biomass sorghum can be indicated for the phytoremediation of environments contaminated with Cu and Ni.

scholarly journals Strategies for Lignin Pretreatment, Decomposition and Modification: A Review

2020 ◽  
Vol 9 (1) ◽  
pp. 01-20
Author(s):  
Leta Deressa Tolesa ◽  
Ming-Jer Lee
Keyword(s):  
Fossil Fuels ◽  
Environmental Concern ◽  
Renewable Resource ◽  
Extraction Methods ◽  
Molecular Structures ◽  
Raw Material ◽  
Gaseous Emissions ◽  
Large Molecules ◽  
Climate Stability

The dependency of chemical industry on nonrenewable sources of energy such as petroleum based carbon feedstock is rising dramatically day to day. Nonetheless, global warming caused by greenhouse gas emissions threatens the environment balance and the climate stability. Accordingly, it is necessary to find a renewable resource to decrease the environmental concern, specifically gaseous emissions from fossil fuels and to provide the energy stock. Outstanding to the significance of lignocellulosic biomass as most remedy to the current environmental issues and substituent of nonrenewable source of energy, this review affords understandings about the role of lignin as polymer and raw material for large molecules. In this review article, types of lignin with their extraction methods, fractionation technology to valuable chemicals, modification of the macromolecules to other polymers with tunableproperties, and an extensive range of applications are discussed widely. The major valuable chemicals produced from lignin via chemical depolymerization are also summarized and illustrated with their molecular structures.

scholarly journals Conserved LBL1-ta-siRNA and miR165/166-RLD1/2 modules regulate root development in maize

Development ◽  
2020 ◽  
Vol 148 (1) ◽  
pp. dev190033
Author(s):  
Vibhav Gautam ◽  
Archita Singh ◽  
Sandeep Yadav ◽  
Sharmila Singh ◽  
Pramod Kumar ◽  
...  
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Lateral Roots ◽  
Root System Architecture ◽  
Maize Root ◽  
Altered Expression ◽  
Auxin Distribution ◽  
Seminal Roots ◽  
Crown Roots

ABSTRACTRoot system architecture and anatomy of monocotyledonous maize is significantly different from dicotyledonous model Arabidopsis. The molecular role of non-coding RNA (ncRNA) is poorly understood in maize root development. Here, we address the role of LEAFBLADELESS1 (LBL1), a component of maize trans-acting short-interfering RNA (ta-siRNA), in maize root development. We report that root growth, anatomical patterning, and the number of lateral roots (LRs), monocot-specific crown roots (CRs) and seminal roots (SRs) are significantly affected in lbl1-rgd1 mutant, which is defective in production of ta-siRNA, including tasiR-ARF that targets AUXIN RESPONSE FACTOR3 (ARF3) in maize. Altered accumulation and distribution of auxin, due to differential expression of auxin biosynthesis and transporter genes, created an imbalance in auxin signalling. Altered expression of microRNA165/166 (miR165/166) and its targets, ROLLED1 and ROLLED2 (RLD1/2), contributed to the changes in lbl1-rgd1 root growth and vascular patterning, as was evident by the altered root phenotype of Rld1-O semi-dominant mutant. Thus, LBL1/ta-siRNA module regulates root development, possibly by affecting auxin distribution and signalling, in crosstalk with miR165/166-RLD1/2 module. We further show that ZmLBL1 and its Arabidopsis homologue AtSGS3 proteins are functionally conserved.

Experimental Investigation of Four Stroke Diesel Engine Performance Using Neem Oil and Neem Oil with Hydrogen as a Fuel

2014 ◽  
Vol 592-594 ◽  
pp. 1559-1563
Author(s):  
Thangaraju Rajasekaran ◽  
K. Duraisamy ◽  
K.R. Arvindd ◽  
D. Thamilarasu ◽  
Venkatachalam Chandraprabu ◽  
...  
Keyword(s):  
Energy Demand ◽  
Alternative Fuels ◽  
Fossil Fuels ◽  
Driving Forces ◽  
Environmental Concern ◽  
Engine Performance ◽  
Calorific Value ◽  
Neem Oil ◽  
Combustion Properties ◽  
Ci Engines

Depletion of fossil fuels, unaffordability of conventional fuels (petrol, diesel) and atmospheric pollution lead researchers to develop alternative fuels. Fuels derived from renewable biological resources used in diesel engines are known as biodiesel. Biodiesel is environmental friendly liquid fuel similar to petrol and diesel in combustion properties. Increasing environmental concern, diminishing petroleum reserves and agriculture based economy of our country are the driving forces to promote biodiesel as an alternate fuel. Hydrogen seems to be viable fuel to meet sustainable energy demand with minimum environmental impact. Hydrogen has high calorific value and clean burning characteristics which makes it effective fuel for future. It was found that hydrogen usage reduce emissions such as CO2and HC. India is one of the largest producers of neem oil and its seed contains 30% oil content. It is an untapped source in India, so the neem oil usage will be a best option. The investigation made on pure neem oil and neem oil with hydrogen addition at different flow rate (2 lpm & 4 lpm) in CI engines. The result shows that, brake thermal efficiency of neem oil with 4 lpm hydrogen was increased to 7.98% compare to pure neem oil at 4 Nm torque and fuel consumption of neem oil with 4 lpm hydrogen was decreased to 13.49% compared to pure neem oil at 4 Nm torque.

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