Coontail (
Ceratophyllum demersum L.) plants when exposed to various concentrations of Pb (1–100
μM) for 1–7
days, exhibited both phytotoxic and tolerance responses. The specific responses were ...function of concentration and duration. Plants accumulated 1748
μg
Pb
g
−1 dw after 7
d which reflected its metal accumulation ability, however most of the metal (1222
μg
g
−1 dw, 70%) was accumulated after 1
d exposure only. The toxic effect and oxidative stress caused by Pb were evident by the reduction in biomass and photosynthetic pigments and increase in malondialddehyde (MDA) content and electrical conductivity with increase in metal concentration and exposure duration. Morphological symptoms of senescence phenomena such as chlorosis and fragmentation of leaves were observed after 7
d. The metal tolerance and detoxification strategy adopted by the plant was investigated with reference to antioxidant system and synthesis of phytochelatins. Protein and antioxidant enzymes viz., superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (GPX, EC 1.11.1.7) ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6) and glutathione reductase (GR, EC 1.6.4.2) showed induction at lower concentration and duration followed by decline. All enzymes except GPX showed maximum activity after 1
d. An increase in cysteine, non-protein thiols (NP-SH) and glutathione (GSH) content was observed at moderate exposure conditions followed by decline. Phytochelatins (PC
2 and PC
3) were synthesized to significant levels at 10 and 50
μM Pb with concomitant decrease in GSH levels. Thus production of PCs seems important for the detoxification of metal, however it may lead to depletion of GSH and consequently oxidative stress. Results suggest that plants responded positively to moderate Pb concentrations and accumulated high amount of metal. Due to metal accumulation coupled with detoxification potential, the plant appears to have potential for its use as phytoremediator species in aquatic environments having moderate pollution of Pb.
Abstract
Rice–wheat production in the Indo-gangetic plains (IGPs) of India faces major concerns such as depleting resources, rice residue burning, excessive fertilizer use, and decreasing nitrogen ...use efficiency. These issues threaten sustainable crop production in the future. Therefore, a field study was conducted during the winter seasons of 2020–21 and 2021–22 to evaluate the effect of combined conventional and nano fertilizers on nitrogen application just before or after irrigation to improve wheat productivity, profitability and NUE under conservation tillage. The study evaluated eight treatment combinations of nitrogen application through conventionally applied urea (46% N) and foliar applied nano urea (4% N) under zero tillage with rice residue retention. Results revealed that growth, physiological indices, yield, and quality parameters were enhanced with the application of 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation alone (T2) or along with a spray of nano urea (T5) compared to other treatments. T5 recorded 7.2%, 8.5%, and 7.8% more plant dry matter, number of tillers, and grain yield, respectively, over the conventional practice of applying 150 kg N/ha in three equal splits as basal and 7–10 days after 1st and 2nd irrigation (T3, farmers practice). Although, T2 showed similar results to T5, T5 recorded significantly higher gross ($2542/ha) and net returns ($1279/ha) than the other treatments. However, the benefit–cost ratio of T2 and T5 was same (2.01). A significant and positive correlation coefficient between grain yield and physiological parameters such as CCI and NDVI confirmed that increasing the nitrogen dose enhanced the chlorophyll content, greenness, and plant vigor. Based on the results, it can be concluded that applying 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation under conservation agriculture, along with a single spray of nano urea (4% N) at 60–65 days after sowing, can improve growth, yield attributes, wheat yield, and NUE compared to farmers practice (T3) in India.
Continuous cultivation of rice–wheat cropping system (RWCS) in Indo-Gangetic Plains of India is showing declining factor productivity coupled with many environmental problems. Diversifying the RWCS ...is one of the environmental friendly options for sustaining food production. Four crop rotations involving maize and sorghum in summer, wheat/potato/mustard in winter followed by short duration mung bean in late spring were studied to identify the most productive and economic combination from 2017 to 2020. Ranking of treatments by Tukey’s test of significance indicated that the maize-potato-wheat (16.49 t ha
−1
year
−1
) combination was best in terms of system productivity calculated in terms of wheat equivalent yield (WEY). Maize-wheat-mung bean crop sequence was most profitable by having higher land use efficiency (LUE = 87.67%) and net return (NR = 1577.1 $ ha
−1
). The gross margin comparison revealed that maize-based crop sequences earned higher gross returns (23.17%), net return (93.66%), and B:C ratio (23.7%) than sorghum-based crop sequences. Soil health parameters were improved under the maize-mustard-mung bean system, which increased the organic carbon content by 28.65%, available N by 34.91% with saving of 47.67% in irrigation water. Adoption of alternate cropping sequences instead of rice–wheat, in the Indo-Gangetic Plains of India, could be more sustainable, profitable, and environment friendly.
Abstract
The intercropping of legumes with cereals help to achieve sustainable intensification by their mutual complementarity at efficiently using radiation, nutrients, etc. Several studies ...indicated such beneficial effects on the other component crop however, little research has been conducted to quantify their effects on the subsequent crop in a cropping system. In this study, the effect of the legume intercropping on the entire cropping system, particularly the maize + legume-wheat system was studied. Four legumes intercropped to maize followed by wheat crop were studied for intensification measures such as wheat equivalent yield (WEY), land equivalent ratio (LER), sustainable value index (SVI), and economic returns. N saving effect of legumes on the subsequent wheat crop was quantified with two N levels. Maize + cowpea-wheat combination was the most productive and economic intercrop combination (LER = 1.71, SVI = 0.96) with an increase in net economic return (43.63%) with a B:C ratio of 1.94. An additional 25% N (37.5 kg ha
−1
) was saved in the wheat crop when the legume intercropping was undertaken with maize. The results suggest that intercropping is the key to diversification and reduces the risk of crop failures by enhancing land-use efficiency, soil fertility, and economic returns under weather vagaries. This will be beneficial to small and marginal farmers of many countries.
•Constructed wetland (CW) efficiently decreased up to 90% BOD from sewage in 24h.•P. australis, T. latifolia and C. esculenta (HGR) were main components of CW.•CW efficiently removed nutrients and ...metals from sewage.
With aim to develop an efficient and ecofriendly approach for on-site treatment of sewage, a sub-surface flow constructed wetland (CW) has been developed by raising potential aquatic macrophytes; Typha latifolia, Phragmites australis, Colocasia esculenta, Polygonum hydropiper, Alternanthera sessilis and Pistia stratoites in gravel as medium. Sewage treatment potential of CW was evaluated by varying retention time at three different stages of plant growth and stabilization. After 6months, monitoring of fully established CW indicated reduction of 90%, 65%, 78%, 84%, 76% and 86% of BOD, TSS, TDS, NO3–N, PO4–P and NH4–N, respectively in comparison to inlet after 36h of retention time. Sewage treatment through CW also resulted in reduction of heavy metal contents. Thus, CW proved an effective method for treatment of wastewater and may be developed along river Ganga stretch as an alternative technology. Treated water may be drained into river to check further deterioration of Ganga water quality.
A Sphingobium sp. strain isolated from radioactive solid waste management site (RSMS) completely degraded 7.98 g/L of tributyl phosphate (TBP) from TBP containing suspensions in 3 days. It also ...completely degraded 20 mM dibutyl phosphate (DBP) within 2 days. The strain tolerated high levels of TBP and showed excellent stability with respect to TBP degradation over several repeated subcultures. On solid minimal media or Luria Bertani media supplemented with TBP, the RSMS strain showed a clear zone of TBP degradation around the colony. Gas chromatography and spectrophotometry analyses identified DBP as the intermediate and butanol and phosphate as the products of TBP biodegradation. The RSMS strain utilized both TBP and DBP as the sole source of carbon and phosphorous for its growth. The butanol released was completely utilized by the strain as a carbon source thereby leaving no toxic residue in the medium. Degradation of TBP or DBP was found to be suppressed by high concentration of glucose which also inhibited TBP or DBP dependent growth. The results highlight the potential of Sphingobium sp. strain RSMS for bioremediation of TBP and for further molecular investigation.
► Extraction of actinide ions viz. Am3+, Pu4+ and UO22+. ► TODGA in room temperature ionic liquids. ► Ion-exchange mechanism of extraction. ► Significantly enhanced separation factors.
Extraction ...behavior of several actinide ions viz. Am3+, Pu4+ and UO22+ was investigated using N,N,N′,N′-tetra-n-octyl diglycolamide (TODGA) as extractant in three different room temperature ionic liquids (RTIL), viz. C4mim+·NTf2- , C6mim+·NTf2- , and C8mim+·NTf2- as the diluents. The solvent systems containing TODGA in the RTILs were found to result in higher distribution ratios for all the actinides (trivalent, hexavalent, tetravalent) as compared to that containing n-dodecane as the diluent. Moreover, the distribution ratio values of the metal ions at lower acidities were found to decrease with increasing feed nitric acid concentration. Extraction was found to be independent of the anion of the aqueous phase. Mechanism of extraction of the actinides was found to be different compared to n-dodecane, molecular diluent. Cation-exchange was found to be the mechanism of extraction followed in RTILs. Effect of carbon chain length of alkyl groups of the RTILs conclusively proved the mechanism of extraction of the actinides by TODGA. Nature of extracted species was also found to differ from n-dodecane. Stripping studies were carried out using complexing agents such as EDTA, DTPA in guanidine carbonate or a buffer mixture.
Crop residue crucially contributes in running the essential agro-environment services. The modernization in crop production with high yielding varieties substantially increased the crop residue and ...its management challenges. The critical window period between two crops like in wheat sowing after rice and sugarcane harvest and poor suitability of some crop residues for animal feed pushed the malpractice of crop residue burning especially in developing countries like India. In long-term, the practice of residue burning along with climate change phenomenon puts the serious challenges in maintaining the quality of natural resources and sustainable crop production system. The precious elements retained in the crop residue are lost upon burning and converted to harmful air pollutants which otherwise can run the essential services in soil-plant system and find industrial applications as feedstock if managed in a sustainable way. The present review article provides critical insights on the current status of residue production and in-situ management of crop residue via different routes using suitable machinery package along with relative advantages and challenges. The prospective of crop residue to derive the soil ameliorants through composting and thermal decomposition approaches are critically discussed in the present review study. Moreover, a brief account is presented on residue derived energy generation (liquid and gaseous fuels) through thermo-chemical and thermal decomposition processes, which can ease the burden of fossil fuels on environment as well as economy of the country. The review article also explores cutting-edge industrial application of crop residue, present challenges and future thrust areas to overcome such issues in the sustainable crop residue management.
•Multi-dimensional negative impacts of residue burning on natural resources•Surface retention of residue suitable for cereal, sugarcane, pulses and oilseed crops•Conventional/reduced tillage led residue recycling suitable for leguminous crops•Need studies on breeding, weed-, nutrient- and insect-dynamics for residue conditions•Enormous potential of crop residue for use in biochar, novel industry and bioenergy•Infrastructure, costly pretreatment and supply process constraints in bioenergy, biochar and industrial applications
The present communication deals with the conformational, vibrational spectroscopic analysis and molecular docking study of an important biorelevant molecule namely ...5-Chloro-2-hydroxy-N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide. We have recorded FTIR spectrum of the target molecule in the spectral range of 4000-400 cm
−1
and this has been correlated with simulated spectra of the most stable conformer. Most of the theoretical frequencies showed good agreement with experimental frequencies and a few were modified. The theoretical computations on the target molecule have been performed at well-known DFT/B3LYP level. The 6-31++G(d,p) was incorporated as a conventional basis set during the complete computations. For normal modes analysis, the potential energy distributions of the most stable conformer were calculated by Molvib program. The NBO calculations were performed to ensure stability of electronic structure and to explore intermolecular interactions. Some important thermodynamical parameters have also been investigated. The effect of aqueous media revealed that target molecule becomes slightly more stable in water phase. HOMO-LUMO gap has been computed to be 4.19 eV.
PDF
