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681.
M. Salman Naeem Saima Javed Vijay Baheti Jakub Wiener M. Usman Javed Syed Zameer Ul Hassan Adnan Mazari Jawad Naeem 《Fibers and Polymers》2018,19(1):71-81
In this work, activated carbon (AC) web was prepared using physical activation under the layer of charcoal in high temperature furnace. The carbonization of acrylic fibrous waste was performed at different temperatures (800 °C, 1000 °C, and 1200 °C) with heating rate of 300 °C/h and at different holding time. At 1200 °C, the heating rate of 300 °C/h and no holding time provided better results of surface area as compared to carbonization at 800 °C and 1000 °C. The activated carbon web (AC) prepared at 1200 °C was used for removal of Acid Red 27 dye from aqueous media by varying different parameters like initial concentration of dye, stirring speed, adsorbent dosage, and pH. The results were evaluated using non-linear forms of Langmuir and Freundlich isotherms. The Freundlich isotherm was found to describe the results more effectively because of non-homogenous surface of activated carbon web. Further, the kinetics of adsorption was examined using linear and nonlinear forms of pseudo 1st order and pseudo 2nd order. 相似文献
682.
Pengfei Wu Guangyu Wang Taimoor Hassan Farooq Qi Li Xianhua Zou Xiangqing Ma 《Journal of Soils and Sediments》2017,17(12):2775-2785
Purpose
In order to manage Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations over the long term, it is critical to understand the species’ response to intraspecific competition at sites with low phosphorus (P). The objective of the present study was to investigate the effects of neighbor competition on the growth of Chinese fir under low P conditions, as well as on the morphology and organic acid content of the root tissues.Materials and methods
We investigated the growth, dry matter accumulation, and organic acid content and type in root tips of Chinese fir cuttings in a greenhouse experiment, which was a design with three factors including competition intensity (single, mild, moderate, and severe), P supply level (0, 6, and 12 mg kg?1 KH2PO4), and competition time (50, 100, and 150 days).Results and discussion
There were no significant interaction effects between all three or any two factors on shoot growth (height or root collar diameter), biomass accumulation, or root:shoot ratio. However, the interactive effects between competition time and competition intensity on all root morphological traits were significant, as was the interaction between P supply and competition (e.g., intensity, time) on root organic acid concentration. The number of organic acid types gradually decreased from the first 50 to 150 days under no P supply and low P supply treatment. Interestingly, capric acid was detected in severe and moderate competition treatments, but not detected under mild competition or in single plant controls at low P. Also, citric acid was detected in P supply treatments (6 and 12 mg kg?1), but not detected in the no P treatment.Conclusions
Mild early-stage intraspecific competition somewhat alleviated the suppressive effect of low P supply on the height of Chinese fir. Seedlings adjusted their shoot and root growth separately to accommodate stress from low P or adjacent competition. Low P supply and competition intensity additively accelerated root volume proliferation, but interactively enhanced organic acid concentration in root tips.683.
Jamiu Oladipupo Azeez Adenike Olabisi Hassan 《Communications in Soil Science and Plant Analysis》2018,49(14):1707-1718
This study evaluated cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) sorption characteristics of three tropical soils. Data obtained conformed to Freundlich sorption model and the S-shaped isotherm curve. Sorption efficiency of Zn and Pb were highest in alkaline soil while slightly acid soil had the highest Cd and Cu sorption efficiency for monometal sorption. In competitive sorption, metals were more sorbed in slightly acid soil while the least efficiency was recorded in acid soil. Distribution coefficient; Kd (average across soil types) in monometal sorption followed the order: Pb > Zn > Cd > Cu. For competitive sorption, the order was Zn > Pb > Cu > Cd. When in competition, Cd was preferentially sorbed in slightly acid and alkaline soils and Zn for acid soil. Conclusively, lead is more in equilibrium solution when in competition with Cd, Zn and Cu making it potential agent of soil and groundwater pollution. 相似文献
684.
Garden rocket (Eruca sativa L.) plants grown in sand culture were irrigated with normal 1/10 Hoagland's medium [low sulfate (SO42?)] or with double SO42? concentration (high SO42?), each supplemented with 0, 2, 10 ppm SeO42? as sodium selenate for 30 days. Increasing SO42? concentration in the nutrient medium diminished SeO42? uptake, foliar hydrogen peroxide (H2O2), and MDA via enhancing the glutathione pool and their enzyme activities. These results showed that increasing SO42?/SeO42? ratio in nutrient medium of rocket plants played an important role in selenate detoxification. 相似文献
685.
The aim of the present study was to compare the effects of drought on some physiological and biochemical parameters and to assess the inducing effects of Penconazole (PEN) on drought tolerance in two cultivars (RGS003 as a drought tolerant and Sarigol as a drought sensitive) of canola. Plants were treated with various PEG concentrations (0, 5, 10, and 15%) without or with PEN (15 mg l?1). Decrease in fresh weight (FW) and dry weight (DW) in Sarigol under drought was higher than that of RGS003. Surprisingly, PEN reversed prominently the negative effects of drought on FW and DW in RGS003. Concomitantly, PEN treatment decreased malondialdehyde content in RGS003 under drought. Moreover, higher content of proline in RGS003 under all drought levels could be considered as a factor for drought tolerance of this cultivar. Superoxide dismutase (SOD), catalase (CAT) and Polyphenol oxidase (PPO) activities were induced by PEN in both cultivars under drought. Inducing effects of PEN on phenylalanine ammonia lyase and thyrosine ammonia lyase activities decreased by increasing of drought levels in both cultivars. In summary, PEN alleviated the negative effects of drought in RGS003 cultivar by inducing activities of SOD, CAT and PPO and proline content comparing to Sarigol. 相似文献
686.
Salman Abdallah Hassan Selmy 《Archives of Agronomy and Soil Science》2018,64(11):1582-1594
The objective of this study was to investigate sorption, desorption, and immobilization of Pb in the clay and calcareous loamy sand soils treated with inorganic ligands (NO3?, Cl? and H2PO4?). Pb sorption was also determined in the presence of oxalate and citrate. The maximum Pb sorption capacities (q) ranged from 42.2 to 47.1 mmol kg?1 for the clay soil, and from 45.2 to 47.0 mmol kg?1 for loamy sand soil. It was observed that the binding energy constant (k) for Pb sorbed onto loamy sand soil (528–1061) is higher than that for clay soil (24.38–55.29). The loamy sand soil-sorbed greater quantities of Pb compared to the clay soil when initial pH was ≥ 3. However, it had lower sorption capacity at the lowest initial pH of 2. Additionally, the greatest Pb sorption and immobilization occurred in the soil treated with H2PO4. In the clay soil, the sorption of Pb was depressed at 0.1 mol kg?1 of Cl?, as compared with other ligands. Concerning organic acids, citrate ligand showed the highest decrease in Pb sorption. It could be concluded that the nature of Pb sorption can depend on the type and quantity of ligands present, as well as the soil type. 相似文献
687.
The maize armyworm, Mythimna separata is a polyphagous insect pest of sporadic occurrence. Thiamethoxam is a neonicotinoid insecticide used for the management of many pests in many parts of the world. To develop a resistance management strategy, selection for resistance, the larval fitness parameters and the biochemical mechanisms of resistance to thiamethoxam were studied for thiamethoxam-selected and susceptible M. separata strains based on laboratory observations. The results of our bioassay showed that the thiamethoxam-selected strain was 17.03-fold more resistant than the susceptible strain. The thiamethoxam-selected strain had prolonged larval durations, lower pre-pupal weight of males, and a longer development time from egg to adult than the susceptible strain. The biochemical analyses showed that the GST, CarE and cytochrome P450 enzymes are associated with the development of thiamethoxam resistance in the thiamethoxam-selected strain of M. separata. In this study, the occurrence of resistance may cost developmental fitness for the thiamethoxam-selected strain and provide useful information for designing management strategies to delay resistance. 相似文献
688.
Kourosh Delavar Hassan Zare-Maivan Mehrdad Behmanesh 《Journal of plant nutrition》2017,40(10):1475-1484
The effects of silicon on seed germination and growth parameters of maize seedlings under normal, aluminum (Al), and sodium chloride (NaCl) stress conditions were investigated. The results indicated a dose-dependent relationship between silicon and growth parameters, except for germination attributes.Application of silicon (2 mM) accelerated amylase activity, decreased abscisic acid content, and increased indoleacetic acid and gibberellic acid contents of seedling, The results suggest that the beneficial effects of silicon, at least in part, are mediated by the balance of phytohormones. Exposure to Al (10 mM) significantly decreased all growth parameters of maize seedlings. Application of 2 mM silicon, however, alleviated Al stress and restored almost all growth attributes. Decrease of Al absorption, increase of fructan content, and improvement of amylase activity were considered as the mechanisms of ameliorative function of silicon in Al-stressed maize seedlings. Exposure to silicon, however, did not show beneficial effects on growth parameters of maize seedlings under salt stress conditions. 相似文献
689.
Hassan Zare-Maivan Narges Khanpour-Ardestani Faezeh Ghanati 《Journal of plant nutrition》2017,40(14):2026-2032
Mycorrhizal fungi affect growth and nutrition of host plants positively. In this research, influence of vesicular-arbuscular mycorrhiza (VAM) ongrowth, chlorophyll content, and potassium (K) and magnesium (Mg) uptake in maize seedlings in pot culture was studied. This experiment was performed using natural soil containing a mixture of spores of Glomus spp. Mycorrhizal spores were exposed to four concentrations of K solution, i.e. 0.61 (soil K content), 0.92, and 1.23 meq/L and three concentrations of Mg, i.e. 4.8 (soil Mg content), 7.2, and 9.6 meq/L concurrently. Plants were watered every 4 days for 16 days with 50 mL distilled water. A pot with sterilized soil was used as negative control. For study of mycorrhizal colonization, very thin manually prepared longitudinal sections of plant roots (>1 mm in diameter) were stained with lactophenol-cottonblue and examined microscopically. Percentage of mycorrhizal colonization was determined using the grid-line intersect method. Samples from root and shoot of maize were collected for further analysis. Results showed mycorrhizal plants had significantly higher dry and fresh weight and chlorophyll content than plants grown in sterilized soil (p ≤ 0.05). Treatments with concentrations of 7.2 meq/L of magnesium alone and in combination with 0.92 meq/L of potassium with7.2 meq/L of Mg had better effect on morphological characters (dry and fresh weight of root and shoot). Mycorrhizal colonization increased Mg uptake but decreased K uptake. 相似文献
690.
Sara Mardaninejad Hamid Zareabyaneh Sayyed Hassan Tabatabaei Abdolrahman Mohamadkhani 《Journal of plant nutrition》2017,40(11):1569-1579
Root water uptake is a component of water balance that has not been clearly understood. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the root water uptake (RWU) by pepper plant under various irrigation water levels was investigated. Irrigation treatments included control (full irrigation level, FI) and three deficit irrigation levels, 80%, 60% and 40% of the plant's water requirement called DI80, DI60 and DI40, respectively. A no-plant cover treatment with three replications was also used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at 10 cm intervals of the soil column. The differences between the measured VSM and the VSM in the next day, and evaporation rate at the soil surface at the same layer of the no-plant cover treatment were calculated and, eventually, the RWU in each layer per day was estimated. The results showed that the maximum and minimum RWUs were found in the FI and DI40 treatments, respectively. The averages of root water uptakes in the DI80, DI60, and DI40 treatments were reduced by 17.08%, 48.72% and 68.25%, respectively. Furthermore, in the DI80 treatment, the reduced rate of water uptake was less than the reduced rate of water applied to the plants. 相似文献