Soil contamination with toxic heavy metals [such as cadmium (Cd)] is becoming a serious global problem due
to rapid development of social economy. Iron (Fe), being an important element, has been found effective in enhancing
plant tolerance against biotic and abiotic stresses. The present study investigated the extent to which different levels of
Ferrous sulphate (FeSO4) modulated the Cd tolerance of rice (Oryza sativa L.), when maintained in artificially Cd
spiked regimes. A pot experiment was conducted under controlled conditions for 146 days, by using natural soil,
mixed with different levels of CdCl2 [0 (no Cd), 0.5 and 1 mg/kg] together with the exogenous application of FeSO4
at [0 (no Fe), 1.5 and 3 mg/kg] levels to monitor different growth, gaseous exchange characteristics, oxidative stress,
antioxidative responses, minerals accumulation, organic acid exudation patterns of O. sativa. Our results depicted that
addition of Cd to the soil significantly (P < 0.05) decreased plant growth and biomass, gaseous exchange parameters,
mineral uptake by the plants, sugars (soluble, reducing, and non-reducing sugar) and altered the ultrastructure of
chloroplasts, plastoglobuli, mitochondria, and many other cellular organelles in Cd-stressed O. sativa compared to
those plants which were grown without the addition of Cd in the soil. However, Cd toxicity boosted the production of
reactive oxygen species (ROS) by increasing the contents of malondialdehyde (MDA), which is the indication of
oxidative stress in O. sativa and was also manifested by hydrogen peroxide (H2O2) contents and electrolyte leakage to
the membrane bounded organelles. Although, activities of various antioxidative enzymes like superoxidase dismutase
(SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants like
phenolics, flavonoid, ascorbic acid, anthocyanin and proline contents increased up to a Cd level of 0.5 mg/kg in the
soil but were significantly diminished at the highest Cd level of 1 mg/kg in the soil compared to those plants which
were grown without the addition of Cd in the soil. The negative impacts of Cd injury were reduced by the application
of FeSO4 which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, minerals uptake together with diminished exudation of organic acids as well as oxidative stress indicators in roots and
shoots of O. sativa by decreasing Cd retention in different plant parts. These results shed light on the effectiveness of
FeSO4 in improving the growth and upregulation of antioxidant enzyme activities of O. sativa in response to Cd
stress. However, further studies at field levels are required to explore the mechanisms of FeSO4-mediated reduction of
the toxicity of not only Cd, but possibly also other heavy metals in plants. 相似文献
Microsystem Technologies - This research article discusses the state of the art synthesis methods for the formation of carbon nanotubes and nanofibers (CNTs/CNFs). Carbon nanotubes have a number of... 相似文献
Flue gas emissions and the harmful effects of these gases urge to separate and capture these unwanted gases. Ionic liquids due to negligible vapor pressure, thermal stability, and wide electrochemical stability have expanded its application in gas separations. A comprehensive overview of the recent developments and applications of ionic liquid membranes (ILMs) for gas separation is given. The three general classifications of ILMs, such as supported ionic liquid membranes (SILMs), ionic liquid polymeric membranes (ILPMs), and ionic liquid mixed‐matrix membranes (ILMMMs) along with their applications, for the separation of various mixed gases systems is discussed in detail. Furthermore, issues, challenges, computational study, and future perspectives for ILMs are also considered. 相似文献
This work describes the contribution of researchers in the field of the energy from Pakistan in the period 1990–2016. A scientometric approach was applied to analyze the scientific publications in the field using the Scopus Elsevier database. Different aspects of the publications were analyzed, such as publication type, major research areas, journals, citations, authorship pattern, affiliations as well as the keyword occurrence frequency. The present research trends are analyzed and future research directions are outlined. The impact factor, h-index and number of citations were used to investigate the strength of active institutes, authors, and journals in the field of the energy in Pakistan. From 1990 to 2016, 991 articles have been published by 2139 authors from 213 research institutes. The total number of citations and impact factor are 10,287 and 2301 respectively, corresponding to 10 citations per paper and an impact factor of 2.32 per publication. The research articles originate primarily from COMSATS, NUST, PIEAS, and PINSTECH. Pakistan has published 60% of publication with the collaboration of the foreign institutes, mainly from the United States, the United Kingdom, China and Malaysia. The core research activities in the field are mainly focused on resource assessment, energy policy, energy efficiency, feasibility study, energy economics, and performance assessment. The most productive journal, author, institution, are renewable & sustainable energy review, Shahbaz M., and COMSATS, respectively. 相似文献
The deterioration of ambient air quality is one of the emerging environmental problems in developing countries of South Asia. Unplanned urbanization, population growth, degradation of vegetation cover and industrial and vehicular emissions, particularly in urban areas, have resulted in substantial rise in the level of air pollutants and emission sources. This study focused on monitoring of different cities as per traffic volume and flow. Air quality monitoring was conducted on hourly basis to determine the major parameters; i.e. PM10, NOx, SO2, CO by using fixed station for 8 h from 1:30 pm to 9:30 pm. All the measuring values were then compared with the National Environment Quality Standards (NEQS) and Air Quality Index (AQI). Results revealed that the concentration of PM10 at the selected areas of these cities ranged from 156 to 390 μg/m3, CO ranged from 1.18 to 6.01 mg/m3, and NOx ranged from 32.65 to 129.47 μg/m3. It was evident that all these concentration had been higher than the permissible limits of NEQS, whereas only SO2 was found within the permissible limits (15.60–110.52 μg/m3). Air Quality Index (AQI) of all the designated points of cities was also assessed, and most of the vehicular and commercial areas had shown unhealthy and severe conditions ranging from 191 to 320, respectively.