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Extracellular polymeric substances (EPS) have extensive demand in industrial products, food processing and environmental remediation. This study aimed to isolate potent bacterial and fungal strains from soils of divergent climatic regions for EPS production. Samples were collected from Koont (sub-humid) and Narin (arid) sites. They were cultured for bacterial and fungal isolation on agar media, and EPS production from them in broth. Significantly greater amounts of EPS were synthesized by two bacterial and a fungal strain. The highest quantity of EPS was produced by fungal strain EPF10 (1.72 g L‒1) followed by bacterial strains EPB9 (1.62 g L‒1) and EPB17 (1.20 g L‒1). Biochemical and molecular characterization revealed these bacterial strains as Pseudomonas aeruginosa EPB9 and Bacillus cereus EPB17, and fungus Aspergillus niger EPF10. The FTIR analysis of EPS revealed stretching vibrations between 3500 and 500 cm−1 confirming their biochemical constituents. This study concludes that microbial strains from harsh climate bear greater potential of high quality EPS production. [ABSTRACT FROM AUTHOR]

The inadequate sanitation, global warming, and dwindling natural oil reserves pose significant threats to global sustainable growth. With this objective, biomass availability for bioenergy production could be ensured alternately by exploring non-conventional plant species and algae. This idea was examined by growing divergent plants and algae species separately in horizontal subsurface flow constructed wetlands and raceway ponds, later collected their biomass for bioethanol determination. Through this approach, sewage was fed to constructed wetlands and raceway ponds as influent and passed through these cultivated systems for wastewater treatment. Although all the four plant and algae species showed efficient results in sewage treatment, however, Ipomoea aquatica and Spirogyra were statistically superior to the others and produced the highest biomass yield of 4.5 and 4.1 kg m−2, respectively. For bioethanol production, alkali–autohydrolysis combined pretreatment followed by enzymatic hydrolysis with two successive incubation periods (12 and 24 h) were employed. Results suggested that Spirogyra biomass rendered greater carbohydrate and ethanol concentration (3.7 and 1.9 mg L−1, respectively) during 24 hours of incubation, whereas Oryza sativa acquired similar carbohydrate concentration as Spirogyra but slightly lower bioethanol yield. This study postulates, Spirogyra is promising for wastewater treatment coupled with bioethanol production. [ABSTRACT FROM AUTHOR]

This study investigated the potential of horizontal subsurface flow constructed wetlands (HSSF-CWs) and open raceway ponds (RWPs) operated under different regimes (plants, impregnated activated charcoal (IAC), and algae) for long-term nitrogen removal to control eutrophication problems. For experimental purposes, five mesocosms HSSF-CWs and two RWPs were set up in Wuxi, China, a temperate climate zone. Three HSSF-CW units were cultivated with different regions' plant species including Nasturtium officinale, Juncus effusus, and Brassica juncea, whereas the one unit packed with IAC and the fifth was left as a control, while two species of algae (Spirogyra and C. pyrenoidosa) were cultured in RWPs. All the amendments tested in this study were almost equally effective for long-term nitrogen removal. The results demonstrated that more than 75.7, 88, and 66%, removal of TN, NH 4 + –N, and N O 3 - –N was achieved by the HSSF-CWs, packed with IAC and N. officinale. Concerning RWPs, both algal species showed almost similar results but slightly lower than others, which may be attributed to the less compatibility with the environment. It was observed that nitrogen removal performance was higher in the winter-spring (March–April) season as compared with winter (January–February). Moreover, all plants, particularly N. officinale growth, were quite steadier than others. The present study validates the impression that both treatment systems were potentially effective in long-term nitrogen removal from sewage and could be considered beneficial to control the eutrophication. [ABSTRACT FROM AUTHOR]

Advancements in the design and technology of constructed wetlands for efficient removal of wastewater contaminants are ever in progress to develop situation-based economical systems. Here, we entrenched two horizontal sub-surface flow constructed wetlands (HSFCW) with either chemical, viz. limestone (HSFCW-LS) or organic, viz. sawdust (HSFCW-SD) substrates, and compared them with biological method, viz. growing of water spinach in floating-bed-constructed wetland (FBCW-WS) to enhance the performance of CWs. Same sewage wastewater was used as influent in each fortified CW replicated thrice. Sewage was replaced weekly, for a total of 12 weeks of experimentation. Sampling of raw sewage from influent was undertaken at the inlet in the beginning, and that of treated effluent from the outlet after a week of treatments. Quality of raw sewage used weekly during experimentation remained almost uniform and near to the wastewater standards. Cumulative data of treated wastewater depicted that the FBCW-WS achieved the highest performance in the removal of total nitrogen (TN), NH 4 + –N, and total phosphorus (TP) with average removal efficiencies of 75.9, 90.5, and 94.3%, respectively. Whereas, HSFCW-SD performed better for N O 3 - –N, FC, and TSS with corresponding removal efficiency of 77.5, 64.3, and 74.2% while HSFCW-LS showed average performance. This study concludes that performance of biological method of macrophyte cultivation (FBCW-WS) is significantly superior to chemical and organic substrates, so it could be more effective, economical, and sustainable approach for sewage treatment. [ABSTRACT FROM AUTHOR]

Sugarcane and sugarbeet farmers experience lower strip cane and beet root yields, respectively, and need to have a comprehensive package of production technology. The current field study evaluated the production and economic prospects of sugarcane-sugarbeet intercropping through enhanced fertilizer dosage for 2 years. Sugarcane variety “HSF-240” and sugarbeet variety “Antak” were grown. Experiment was performed in randomized complete block design with two-factorial arrangement, and it was quadruplicated. Factor-1 treatments in main plots comprised of sole cultivation of sugarcane and sugarbeet as well as intercropping of both. Sugarbeet was intercropped with sugarcane on 90-cm-spaced rows. Factor-2 in subplots included various fertilizer (F) rates equally that of nitrogen (N), phosphorus (P) and potassium (K) as N-P2O5-K2O, viz. F0, F100, F150, F200, F250 and F300, representing 0, 100, 150, 200, 250 and 300 kg ha−1, respectively. Data regarding crop yield attributes (millable canes and beets per m2, weight of stripped cane and beet root), yield of crops and sugar production rendered non-significant difference between intercropping and sole cultivation system of sugarcane and sugarbeet; although there were slightly higher values for sole planting. Number of millable canes and beets per m2, weight per stripped cane and beet root, stripped cane and beet yield, and sugar recovery and yield significantly enhanced with each increment of NPK level. The most appropriate dose of NPK was 250 kg ha−1 with respect to crop and sugar production as well as for maximum economic returns from sugarcane as higher NPK dose 300 kg ha−1 did not had further significant positive effect. However, single root weight, crop and sugar yield of sugarbeet were significantly higher with 300 kg NPK ha−1 as compared to that from 250 kg NPK ha−1 both under sole and intercropping plantation system. Sugarcane-sugarbeet intercropping turns superior to traditional sole cultivation system under enhanced plant nutrient dosage up to 250 kg NPK ha−1, whereas further increase in fertilizer dose reduces the economic returns. Beyond this level of NPK fertilizer, the purity of sugar and its recovery could become deteriorated. [ABSTRACT FROM AUTHOR]

Greenhouse studies were undertaken to evaluate the genetic performance of two cucumber genotypes (Long Green and Summer Green) at four salinity levels (0, 25, 50, and 100 mM NaCl). Seeds were pretreated with 50 mg salicylic acid (SA) L−1 and 25 mg kinetin (Kin) L−1. Under hydroponic conditions, seed pretreatment with Kin significantly increased shoot and root dry biomass and reduced the salt injury index in both genotypes. SA reduced the salt injury index of Long Green cucumbers. In a pot experiment, Kin treatment reduced Na+ and increased K+ concentration, photosynthesis, and chlorophyll content in both genotypes, compared to SA under saline soil conditions. Kin treatment improved fruit yield in both genotypes, while SA had a statistically significant effect on Long Green fruit yield. The application of SA and Kin enhanced salinity tolerance in both genotypes by the activation of antioxidants, especially superoxide dismutase, peroxidase, and catalase, which offset oxidative injury. Summer Green exhibited better salt tolerance and improved osmoregulation that resulted in higher fruit yield than Long Green. It was concluded that cucumber genotypes differed in salt tolerance, and seed pre-treatment with Kin minimized salt stress injury, even in sensitive genotype which could sustain crop production under saline conditions. [ABSTRACT FROM AUTHOR]

Adsorption-desorption of iodine in two forms, viz., iodide (I) and iodate (IO), in three types of soil were investigated. The soils were: red soil developed on Quaternary red earths (REQ)- clayey, kaolintic thermic plinthite Aquult, Inceptisol soil (IS) and alluvial soil (AS)-Fluvio-marine yellow loamy soil. The isothermal curves of iodine adsorption on soils were described by Langmuir and Freundlich equation, and the maximum adsorption values ( y) were obtained from the simple Langmuir model. As compared with the iodide, the iodate was adsorbed in higher amounts by the soils tested. Among three soils, the REQ soil adsorbed more iodine (I and IO) than the IS and AS. The distribution coefficient ( K) of iodine in the soils decreased exponentially with increasing iodine loading concentration. Desorption of iodine in soil was increased correspondingly with increasing adsorption values. The REQ soil had a greater affinity for iodine than the IS and AS at the same iodine loadings. In the pot experiment cultivated with pakchoi ( Brassica chinensis L.) and added with two exogenous iodine sources, the iodide form was quickly taken up by pakchoi and caused more toxicity to the vegetable. The rate of iodine loss from soil was higher for iodide form as compared with the iodate. The iodine bioavailability was the highest but the persistence was the weakest in AS among the three soils tested, and the REQ soil showed just the opposite trend to that of the AS soil. This study is of theoretical importance to understand the relationship between iodine adsorption-desorption characteristics and their bioavailability in different soils and it also has practical implications for seeking effective alternatives of iodine biofortification to prevent iodine deficiency disorders. [ABSTRACT FROM AUTHOR]

Introduction: Cadmium (Cd) in plants interrupts numerous metabolic processes and reduces the water and nutrient uptake that cause chlorosis, growth retardation, and ultimately plant death. Response of Brassica napus L. to calcium (Ca) enrichment in growth medium for reducing Cd toxicity stress by strengthening the photosynthesis organelles and their functionality was explored in this study. Materials and methods: B. napus seedlings of two cultivars (ZS 758 and ZS 72) were exposed to Cd toxicity at 500 μM in hydroponics, and it was ameliorated with Ca at 2.0 mM. The study included determinations and evaluations pertaining to physiological attributes of plant growth, chlorophyll, and photosynthesis. Results and discussion: Cadmium stress significantly depressed the seedling growth and reduced photosynthetic rate (Pn), stomatal conductivity (Gs), and transpiration rate (Tr). Further, Cd toxicity markedly decreased the electron transport rate of PSII, effective quantum yield of photochemical energy conversion in PSII [Y(II)], photosynthetic active radiation, coefficient of photochemical quenching (qP), and chlorophyll fluorescence decrease ratio (R). Addition of Ca in Cd-stressed plants antagonized the toxicity effects on all the above-mentioned attributes. Calcium amendment also reversed the Cd stress-induced increase in intercellular CO concentration (Ci) and non-photochemical quenching, and countered the Cd accumulation in seedlings. Conclusion: This study suggests that Ca in the proximity of plasma membrane is proficient in alleviating Cd toxicity by reducing the cell-surface negativity and competing for Cd ion influx. Consequently, both the plant growth and activity of diurnal photosynthetic system remain the least altered under Cd-provoked toxicity stress. [ABSTRACT FROM AUTHOR]

Increased ultraviolet radiations intruding on the earth pose a serious threat to the unadapted plants. Due to the ecological and economic significance of mat rush ( Juncus effusus L.), an in vitro experiment was conducted to unveil the toxic effects of ultraviolet radiation (UV-C) on its physiology and ultrastructure. The basal culm segments of plant were used for in vitro treatments of UV-C with different exposure times (15, 30 and 45 min). The treated segments were first transferred to 1/2 strength MS media and then shifted to soil-perlite mixture for further growth. With increasing exposure time to UV-C, there was significant reduction in plant growth and biomass, and increased activities of antioxidant enzymes. Physiological and ultrastructural alterations were observed in the shoots of UV-treated plants. These plants exhibited significant reduction in chlorophyll contents and noticeable modifications at the ultra-cellular levels. Cell and chloroplast size reduced greatly, and there was appearance of higher amounts of plastoglobuli in chloroplasts resulting in disruption of thylakoid integrity. The functional and ultrastructural alterations in the stressed plants suggest a potential hazard of UV-C radiation on this aquatic flora and thus the ecosystem. The study further explores that UV-C radiations trigger these modifications mainly by damaging the chloroplast. [ABSTRACT FROM AUTHOR]

The present study reports the operation of a laboratory-scale anoxic sulfide oxidizing (ASO) reactor to investigate the effects of influent nitrite to bisulfide molar ratios of 0.58, 1.45, and 1.75 upon the simultaneous bisulfide and nitrite removal rates from the synthetic wastewater. For all tested ratios, very high bisulfide removal percentages (above 99 %) were observed. The mass balance analysis suggested that the bisulfide oxidation was incomplete. The sulfate formation decreased with the increasing influent sulfide concentrations. An influent bisulfide concentration above 1400 mg S / 1 accompanied by high effluent nitrite might have some inhibitory effect on the complete sulfide oxidation to sulfate. Nitrite removal percentage for the 0.58 ratio was in the range of 71.89-86.86 %, showing some fluctuations in the working performance of the ASO reactor. Nitrite removal at the 1.45 ratio ranged from 72.70-87.30 %. Comparatively higher nitrogen removal (78-94 %) was observed for the 1.75 ratio. The application of an influent nitrite to sulfide molar ratio of 1.75 would be a better choice for higher nitrite and bisulfide removal efficiencies in an ASO reactor. [ABSTRACT FROM AUTHOR]

Disparity in the root morphology of six rice ( Oryza sativa L.) genotypes varying in potassium (K) efficiency was studied with three K levels: 5 mg/L (low), 10 mg/L (moderate) and 40 mg/L (adequate) in hydroponic culture. Morphological ’parameters included root length, surface area, volume and count of lateral roots, as well as fine (diameter<0.2 mm) and thick (diameter>0.2 mm) roots. The results indicate that the root growth of all genotypes was reduced under low K, but moderate K deficiency increased the root length of the efficient genotypes. At deficient and moderate K levels, all the efficient rice genotypes developed more fine roots (diameter<0.2 mm) than the inefficient ones. Both fine root count and root surface area were found to be the best parameters to portray K stress in rice. In accordance with the root morphology, higher K concentrations were noted in shoots of the efficient genotypes when grown at moderate and deficient K levels, indicating that root morphology parameters are involved in root uptake for K and in the translocatio of K up to shoots. K deficiency affected not only the root morphology, but also the root ultra-structure. The roots of high-efficient genotypes had stronger tolerance to K deficient stress for root membrane damage, and could maintain the developed root architecture to adapt to the low K growth medium. [ABSTRACT FROM AUTHOR]

The effect of Al and Cd on the growth, photosynthesis, and accumulation of Al, Cd and plant nutrients in two soybean genotypes were determined using hydroponic culture. There were six treatments: pH 6.5; pH 4.0; pH 6.5+1.0 μmol/L Cd; pH 4.0+1.0 μmol/L Cd; pH 4.0+150 μmol/L Al; pH 4.0+1.0 μmol/L Cd+150 μmol/L Al. The low pH (4.0) and Al treatments caused marked reduction in root length, shoot height, dry weight, chlorophyll content (SPAD value) and photosynthetic rate. Al-sensitive cv. Zhechun 2 accumulated comparatively more Al and Cd in plants than Al-tolerant cv. Liao 1. Compared with pH 6.5, pH 4.0 resulted in significant increase in Cd and Al concentration in plants. Combined application of Cd and Al enhanced their accumulation in roots, but caused a reduction in shoots. The concentrations of all 10 nutrients (P, K, Ca, Mg, Fe, Mn, Cu, Zn and B), except Mo were also increased when plants were exposed to pH lower than pH 6.5. Al addition caused a reduction in the concentration of most nutrients in plant roots and shoots; but K, Mn and Zn in roots were increased. Treatments with Cd alone or together with Al reduced the concentrations of all the plant nutrients in plants. Al-sensitive genotype Zhechun 2 has lower nutrient concentration than Al-tolerant genotype Liao 1. The current findings imply that Al and Cd are synergistic in their effect on plant growth, physiological traits and nutrient uptake. [ABSTRACT FROM AUTHOR]

Pesticide residue contamination in potato field is posing a significant threat to health and the environment. Hence, pesticide residue management is a need of time. Thus, the present study was conducted with objectives of minimizing pesticide residue using cropping system (CS) and nutrient management (NM) treatments. Treatments include two CS, i.e. CS1 (potato-mungbean), CS2 (potato-maize) and six NM (NM0 (no use of fertilizers), NM1 (poultry manure @ 20 t ha−1), NM2 (compost @ 20 t ha−1), NM3 (farmyard manure (FYM) @ 20 t ha−1), NM4 (NPK recommended dose), and NM5 (biofertilizer PSB 2.5 kg ha−1 + NFB 2.5 kg ha−1) + FYM @ (10 t ha−1) + half recommended dose of N-P-K (Urea-DAP-SOP)). A study was conducted at a pesticide-contaminated field of village Tajak tehsil Hazro, district Attock. Data about tuber yield, biological yield, harvest index, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and pesticide residue (bifenthrin and imidacloprid) in soil and plant were collected from all treatments during 3 years (2018 to 2020). Results showed that potato-mungbean cropping system significantly increased biological (2.5%) and tuber yield (2.9%) as compared to CS2. Application of FYM in combination with biofertilizer and 50% recommended dose of NPK resulted in higher biological yield (43.2%) and tuber yield (74%) as compared to control. Potato-mungbean CS reduced bifenthrin (5.9%) and imidacloprid (4.0%) residues significantly as compared to the CS2, while NM5 significantly decreased the residues bifenthrin (46.61%) and imidacloprid (62.96%) as compared to the control. A positive relationship was observed between MBC and MBN with biological and tuber yield, while the association was negative with pesticide residues. Hence, it can be concluded that a legume-based cropping system with NM5 could help minimize pesticide contamination by increasing MBC and MBN, which could further lead to sustainable potato yield under contaminated fields. Graphical Abstract: Pesticide residue contamination in potato field is posing a significant threat to health and the environment. Hence, pesticide residue management is a need of time. Thus, the present study was conducted with objectives of minimizing pesticide residue using cropping system (CS) and nutrient management (NM) treatments. Treatments include two CS, i.e. CS1 (potato-mungbean), CS2 (potato-maize) and six NM (NM0 (no use of fertilizers), NM1 (poultry manure @ 20 t ha−1), NM2 (compost @ 20 t ha−1), NM3 (farmyard manure (FYM) @ 20 t ha−1), NM4 (NPK recommended dose), and NM5 (biofertilizer PSB 2.5 kg ha−1 + NFB 2.5 kg ha−1) + FYM @ (10 t ha−1) + half recommended dose of N-P-K (Urea-DAP-SOP)). A study was conducted at a pesticide-contaminated field of village Tajak tehsil Hazro, district Attock. Data about tuber yield, biological yield, harvest index, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and pesticide residue (bifenthrin and imidacloprid) in soil and plant were collected from all treatments during 3 years (2018 to 2020). Results showed that potato-mungbean cropping system significantly increased biological (2.5%) and tuber yield (2.9%) as compared to CS2. Application of FYM in combination with biofertilizer and 50% recommended dose of NPK resulted in higher biological yield (43.2%) and tuber yield (74%) as compared to control. Potato-mungbean CS reduced bifenthrin (5.9%) and imidacloprid (4.0%) residues significantly as compared to the CS2, while NM5 significantly decreased the residues bifenthrin (46.61%) and imidacloprid (62.96%) as compared to the control. A positive relationship was observed between MBC and MBN with biological and tuber yield, while the association was negative with pesticide residues. Hence, it can be concluded that a legume-based cropping system with NM5 could help minimize pesticide contamination by increasing MBC and MBN, which could further lead to sustainable potato yield under contaminated fields. [ABSTRACT FROM AUTHOR]