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The issue of water scarcity in Pakistan is a significant challenge which is due to exacerbated population growth as well as increase in freshwater demand. The application of wastewater for irrigation, especially in semi-urban regions, can indeed be a practical solution due to its ready availability and affordability. While wastewater can serve as a valuable resource in water-scarce regions, its use must be carefully managed to minimize potential risks to plant health, soil fertility, and human well-being. A study was conducted aiming to assess the seasonal changes in physicochemical properties of irrigated wastewater and their influence on morphological, physiological and biochemical responses of sugarcane (Saccharum officinarum L.). Sugarcane plants were grown for consecutive two years in peri-urban agricultural areas near the water channels. Sugarcane plants were grown in two different fields and irrigation of the crop was done with wastewater and freshwater, respectively. Water (wastewater and freshwater) and plant samples were collected four times in a year in different seasons (winter, spring, summer, fall) for two consecutive years (2016-2017). All the collected data had been subjected to multivariate analysis of variance (MANOVA) for assessing the impa ct of seasonal variation on plant responses under the influence of irrigated wastewater. The findings from the study highlighted the complex relationship between wastewater irrigation and the physiological responses of sugarcane plants. The observed increase in antioxidant activities of wastewater irrigated plants compared to freshwater irrigated plants suggested that sugarcane may undergo biochemical adjustments to cope with the stress induced by the contaminants present in the wastewater. Moreover, the significant differences in plant mineral contents across different seasons were observed which indicated the dynamic nature of nutrient availability in the irrigation water and its impact on plant growth and development. We concluded that wastewater irrigation can affect the potential output of the agriculture sector by altering plant physiology which underscores the importance of considering the quality of irrigation water in agricultural practices. For future prospectives, the study can be extended to other crops to develop comprehensive strategies for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Introduction: The escalating threat of drought poses a significant challenge to sustainable food production and human health, as water scarcity adversely impacts various aspects of plant physiology. Maize, a cornerstone in staple cereal crops, faces the formidable challenge of drought stress that triggers a series of transformative responses in the plant. Methods: The present study was carried out in two sets of experiments. In first experiment, drought stress was applied after maintaining growth for 45 days and then irrigation was skipped, and plant samples were collected at 1st, 3rd and 6th day of drought interval for evaluation of changes in plant growth, water relation (relative water content) and antioxidants activity by inoculating indigenously isolated drought tolerant biofilm producing rhizobacterial isolates (Bacillus subtilis SRJ4, Curtobacterium citreum MJ1). In the second experiment, glycine betaine was applied as osmoregulator in addition to drought tolerant PGPR to perceive modulation in photosynthetic pigments (Chlorophyll a and b) and plant growth under varying moisture stress levels (100, 75 and 50% FC). Results and discussion: Results of the study revealed upsurge in root and shoot length, fresh and dry biomass of root and shoot besides increasing chlorophyll contents in water stressed inoculated plants compared to uninoculated plants. Glycine betaine application resulted in an additional boost to plant growth and photosynthetic pigments, when applied in combination with bacterial inoculants. However, both bacterial inoculants behaved differently under drought stress as evident from their biochemical and physiological attributes. Isolate SRJ4 proved to be superior for its potential to express antioxidant activity, leaf water potential and relative water contents and drought responsive gene expression while isolate MJ1 showed exclusive increase in root dry biomass and plant P contents. Though it is quite difficult to isolate the bacterial isolates having both plant growth promoting traits and drought tolerance together yet, such biological resources could be an exceptional option to be applied for improving crop productivity and sustainable agriculture under abiotic stresses. By exploring the combined application of PGPR and glycine betaine, the study seeks to provide insights into potential strategies for developing sustainable agricultural practices aimed at improving crop resilience under challenging environmental conditions. [ABSTRACT FROM AUTHOR]

The highest reduction in sorption occurred with SO SB 4 sb SP 2- sp ions, which were lowered to 74%, while Cd sorption onto TiO SB 2 sb NPs (A) showed that PO SB 4 sb SP 3- sp and NO SB 3 sb SP - sp presence reduced Cd removal to 75.87 and 74.66%, respectively (A). Using (A) TiO SB 2 sb NPs, it was revealed that maximum Cd uptake by TiO SB 2 sb NPs from wastewater occurs at an optimum pH value of 4.3 for both TiO SB 2 sb NPs (A, B). In order to pronounce the Cd sorption on the surface of TiO SB 2 sb NPs, binding energy ( I E i ) of the Cd sorption was also be computed by using Dubinin-Radushkevich model. Keywords: cadmium; clean water and sanitation (SDGs 6); green synthesis; nanoparticles; sorption; titanium dioxide nanoparticles EN cadmium clean water and sanitation (SDGs 6) green synthesis nanoparticles sorption titanium dioxide nanoparticles 637 657 21 05/12/22 20220501 NES 220501 1 Introduction Green nanotechnology is one of the emerging technologies that has revolutionized the numerous science disciplines due to wide-range of applications in almost every aspect of daily life. [Extracted from the article]

Among different abiotic stresses, drought stress is the leading cause of impaired plant growth and low productivity worldwide. It is therefore essential to understand the process of drought tolerance in plants and thus to enhance drought resistance. Accumulating evidence indicates that phytohormones are essential signaling molecules that regulate diverse processes of plant growth and development under drought stress. Plants can often respond to drought stress through a cascade of phytohormones signaling as a means of plant growth regulation. Understanding biosynthesis pathways and regulatory crosstalk involved in these vital compounds could pave the way for improving plant drought tolerance while maintaining overall plant health. In recent years, the identification of phytohormones related key regulatory genes and their manipulation through state-of-the-art genome engineering tools have helped to improve drought tolerance plants. To date, several genes linked to phytohormones signaling networks, biosynthesis, and metabolism have been described as a promising contender for engineering drought tolerance. Recent advances in functional genomics have shown that enhanced expression of positive regulators involved in hormone biosynthesis could better equip plants against drought stress. Similarly, knocking down negative regulators of phytohormone biosynthesis can also be very effective to negate the negative effects of drought on plants. This review explained how manipulating positive and negative regulators of phytohormone signaling could be improvised to develop future crop varieties exhibiting higher drought tolerance. In addition, we also discuss the role of a promising genome editing tool, CRISPR/Cas9, on phytohormone mediated plant growth regulation for tackling drought stress. [ABSTRACT FROM AUTHOR]

Improving growth and productivity of plants that are vulnerable to environmental stresses, such as heavy metals, is of significant importance for meeting global food and energy demands. Because heavy metal toxicity not only causes impaired plant growth, it has also posed many concerns related to human well-being, so mitigation of heavy metal pollution is a necessary priority for a cleaner environment and healthier world. Hydrogen sulfide (H2S), a gaseous signaling molecule, is involved in metal-related oxidative stress mitigation and increased stress tolerance in plants. It performs multifunctional roles in plant growth regulation while reducing the adverse effects of abiotic stress. Most effective function of H2S in plants is to eliminate metal-related oxidative toxicity by regulating several key physiobiochemical processes. Soil pollution by heavy metals presents significant environmental challenge due to the absence of vegetation cover and the resulting depletion of key soil functions. However, the use of stress alleviators, such as H2S, along with suitable crop plants, has considerable potential for an effective management of these contaminated soils. Overall, the present review examines the imperative role of exogenous application of different H2S donors in reducing HMs toxicity, by promoting plant growth, stabilizing their physiobiochemical processes, and upregulating antioxidative metabolic activities. In addition, crosstalk of different growth regulators with endogenous H2S and their contribution to the mitigation of metal phytotoxicity have also been explored. [ABSTRACT FROM AUTHOR]

The rapid mineralization of organic nitrogen (ON) in semiarid soils frequently results in large N losses, reduced crop yields, and environmental pollution. The addition of manures to soil has the potential to promote microbial growth, increase N immobilization, reverse the decline in soil organic matter, and enhance soil quality. In this study, three contrasting organic manures were used to determine their influences on amino acid and oligopeptide dynamics in soil (as key component of the soil ON‐cycle) as well their effects on the size of the microbial biomass and N immobilization. Laboratory incubation experiments were set up with soil obtained from experimental field trial sites for growing maize. Treatments included soil amended with either poultry manure (PM), farmyard manure, pressmud, or unamended (control). Radio‐ and stable‐isotope (14C–15N) techniques were used to assess ON mineralization, immobilization, and leaching using the amino acids alanine and valine as well as the oligopeptides trialanine and valine–proline–proline as model substrates. Quantitative polymerase chain reaction was used to determine soil bacterial biomass. The results showed that all manures increased microbial growth and total soil amino acids as well as protein content. Greater immobilization and subsequently lower mineralization and leaching were also observed in the manure‐amended soils, with this being most pronounced in the PM treatment. The application of PM also enhanced the half‐lives of the ON compounds in soil and increased the size of the bacterial biomass. Overall, our findings indicate that manure amendments, particularly PM, can help promote more efficient ON cycling in semi‐arid ecosystem by controlling N mineralization, reducing amino acid leaching, and elevating oligopeptide immobilization. [ABSTRACT FROM AUTHOR]

Potassium (K) deficiency is becoming a major productivity constraint in semi-arid agriculture. It is an essential mineral nutrient that has key role in various plant physiological and biochemical functions. Balanced nutrient application always tends to ensure better plant growth and development. Therefore, in the present study, efficacy of different K fertilizers for mediating maize plant growth and productivity in the presence and absence of KSB inoculant was assessed. A potassium solubilizing rhizobacterial strain, Klebsiella oxytoca KSB-17, was used in a 5 × 2 factorial pot experiment involving maize plant. The treatments comprised of control, waste mica (WM), K chemical fertilizer (KCF), WM-enriched compost (WMEC) and KCFenriched compost (KCFEC). Compared to control treatment, KCF fertilization increased all plant physiological parameters both in presence and absence of KSB inoculation. From the results obtained, KCFEC followed by CF alone with KSB, demonstrated the most pronounced effect with significant increase in plant height (50%), shoot biomass (59%), root biomass (73%), root length (92%), plant K uptake (154%), grain starch (16%), protein (31%), oil content (22%) as well as photosynthetic rate (104%), transpiration rate (30%) and water use efficiency (54%) compared to control. Potassium solubilizing bacteria (KSB) prompted down-regulation of plant antioxidant enzyme activities against all K fertilizer treatments. Compared to control treatment, catalase (CAT) activity decreased significantly on application of KCF as well as with KCFEC in the presence of KSB inoculation. Regardless of KSB inoculation, plant growth, physiological, antioxidant and K nutritional traits showed slight improvement with either of WM fertilizers compared to control. Our findings concluded that K enriched compost with efficient KSB inoculant can be used to enhance maize growth and productivity in semi-arid agroecosystems. [ABSTRACT FROM AUTHOR]

Global warming has been increasing manifold in recent times, and this may cause tremendous economic losses in the near future. Recently, heat stress is considered one of the major constraints affecting crop growth and yield at world level. Heat stress reduced the plant growth, photosynthesis, mineral nutrients, and yield attributes. Heat stress caused both ultrastructural alterations and oxidative stress in different parts of plants. Plants can tolerate certain levels of heat stress by maintaining membrane stability, adjusting antioxidants and compatible solutes, and scavenging reactive oxygen species. Heat tolerance in plants can be improved by selecting heat-tolerant cultivars, genetic engineering, and exogenous application of osmolytes, microbes, mineral nutrients, soil amendments, and proper agricultural practices. This review is devoted to discuss the plants' physiological and biochemical responses to heat stress and various integrated approaches to improve heat stress tolerance in plants. [ABSTRACT FROM AUTHOR]

Phytoremediation, assisted with different amendments, is receiving much attention around the world due to its high efficiency, low cost and ease of handling. The current study was constructed to determine the combined performance of the citric acid (CA) and 5-aminolevulinic acid (5-AA) to enhance chromium (Cr) extraction through sunflower. Healthy seeds of sunflower were grownup in Cr contaminated soil (0, 5, 10 & 20 mgkg-1) and externally provided with CA (0, 2.5 &5 mM) and 5-AA (0, 10 & 20 mg L-1) at juvenile stage. The results showed a significant reduction in sunflower agronomic traits and biomass under Cr stress. In response to Cr stress, higher production of the reactive oxygen species (ROS) significantly reduced soluble proteins, photosynthetic pigments and activities of anti-oxidant enzymes. The combined addition of CA and 5-AA considerably mitigated the Cr-induced toxic effects on sunflower. Citric acid (CA) and 5-AA application enhanced plants' agronomic and physiological attributes by lowering electrolyte leakage and ROS production. Furthermore, the introduction of 5-AA and CA significantly up-regulated the actions of antioxidants enzymes in leaves and root of sunflower. With increasing soil Cr concentration, more Cr uptake and accumulation was observed which was further boosted with mutual applications of CA and 5-AA. Results of our work summarize that, CA and 5-AA combined application can effectively mitigate Cr stress and enhance Cr extraction capability of sunflower. [ABSTRACT FROM AUTHOR]

Being a primary toxic heavy metal, lead (Pb) contamination presents an imposing environmental and public health concern worldwide. A Bacillus subtilis PbRB3, displaying higher Pb tolerance, was isolated from the textile effluent. The bacterial culture was able to remove >80% of Pb from culture solution. Upon screening in the presence of Pb, PbRB3 strain exhibited significant plant growth promoting potential. A 3 weeks long pot experiment was established to examine the capability of PbRB3 strain for physiological and biochemical traits, and Pb accumulation tendency of mung bean at 250 and 500 mg kg−1 of Pb toxicity, respectively. With respect to control treatments, photosynthetic pigments, protein synthesis, net assimilation rate, transpiration rate and stomatal conductance were significantly constrained by Pb toxicity levels. Intrinsic and instantaneous water use efficiencies were considerably improved in inoculated plants under Pb toxicity. Compared to inoculated control, significantly higher superoxide dismutase activity in both Pb toxicity treatments, while higher malondialdehyde contents only at Pb500 treatment was recorded with PbRB3 inoculation. Catalase activity between Pb250 and Pb500 treatments was comparable at both inoculation level. Moreover, PbRB3 inoculation led to significantly higher peroxidase activity under Pb toxicity treatments compared to inoculated control. The PbRB3 inoculation led to comparable differences in root Pb content between Pb250 and Pb500 treatments. These results suggest that inoculation of Pb tolerant, Bacillus subtilis PbRB3, could be employed to improve mung bean growth potential and adaptation against Pb toxicity, and thereby accelerated Pb rhizoaccumulation from metal contaminated environment. • A Bacillus subtilis PbRB3 was isolated from textile effluent. • PbRB3 removed >80% of Pb from spiked culture solution. • Photosynthetic pigments impaired by Pb toxicity even upon inoculation. • PbRB3 improved plant water use efficiency at Pb250 and Pb500. • PbRB3 mediated Pb translocation from root to aerial part. [ABSTRACT FROM AUTHOR]

Excessive use of nitrogenous fertilizers and their improper management in agriculture causes nitrate contamination of surface and groundwater resources. This study was conducted along the seasonally flooded alluvial agricultural area of Indus River Basin to determine the spatial and temporal dynamics of nitrate concentrations in the groundwater along the river. Total of 112 samples were collected from shallow (30–40 ft) and deep groundwater (120–150 ft) wells at seven sites, 25 km apart from each other and covered an area of 170 km along the river, during four sampling campaigns between October 2016 to May 2017 i.e. in start, mid and end of dry season. The study period covered the whole agricultural cycle including the wet summer season with no agricultural activities under flooding and the sampling sites were always less than 2 km from the river bank. Nitrate concentrations of shallow wells were 15–54 and 20–45 mg L−1 during the start and middle of dry season, respectively. However, at the end of the dry season, the highest nitrate concentrations of 35–75 mg L−1 were recorded and 70% of these samples contained nitrate concentrations above the permissible limit 50 mg L−1. Similar seasonal patterns of nitrate concentrations were observed in deep wells, however, δ18O data suggested lower recharge in deep well than shallow wells. The results illustrated that high nitrate concentrations in shallow wells were associated with high δ18O values indicating that the quantity of evaporated water infiltrated from the floodplain, possibly from distribution channels, along with the nitrate polluting shallow wells more than the deep wells. At the end of the dry season, nitrate concentrations exceeded the permissible limits in both shallow and deep wells, which possibly happened due to the horizontal movement of groundwater along with the nitrate mixing during vertical seepage of river water to the aquifers. Image 1 • Patterns of nitrate in groundwater along the Indus River Basin (IRB) were studied. • Shallow wells had higher nitrate concentrations than deep wells. • Nitrate concentrations of 70% samples were 35–75 mg L−1 after flooding. • δ18O values showed strong flooding effects on groundwater nitrate concentrations. [ABSTRACT FROM AUTHOR]

Declining soil fertility and crop yields are common in arid and semi-arid areas. Sustainable technologies that halt or reverse this trend are required to ensure food security. The use of compost for soil amendment should build soil resilience to drought. However, manure (which is a raw material in compost production) is used as a fuel in many semiarid regions of the world. To encourage farmers to change from using manure or composts as fuel to adopting them as soil additives, it will be necessary to demonstrate the production benefits associated with such additives. A 2-yr field experiment was conducted in a semi-arid (steppe) desert environment in Pakistan on sandy-loamy soils. Poultry manure compost (PMC), pressmud compost (PrMC), and urea (U) were compared in a maize-maize (Zea mays L.) cropping system. The PMC and PrMC application increased soil organic carbon (SOC) and N as well as the soil's moisture content, but decreased the soil electrical conductivity (ECe) and pH after 2 yr. Replacing 25% of the U with PMC increased the mineral N and mean crop growth rate by 46%, the net assimilation rate by 30% and the yield by 219%, compared to the control. These results were comparable to applications of U alone and PMC with urea in a 25:75 application ratio. These results demonstrate that in semiarid regions, adding manure or compost as a soil additive improves the soil's yield potential. [ABSTRACT FROM AUTHOR]

Relations between nitrogen (N) nutrition and salinity tolerance in plants are multifaceted and varies significantly depending on many soil and plant factors. Saline environment might experience an N dilemma due to the opposing effects of salt ions on N uptake, translocation and metabolism within the plant body. Adequate regulation of N under saline conditions can be a promising approach to alleviate salinity’s effects on plants by ameliorating ion toxicity and nutrient imbalances through its impacts on the uptake and redistribution of salt ions within the plant. Certain N-containing compounds including proline, glycine betaine, proteins and polyamines help the plants to tolerate salinity through their involvement in improving water uptake and water use efficiency, membrane integrity, enzyme activation, hormonal balance, chlorophyll synthesis, stimulation of photosystems and CO2 assimilation under salinity stress. Nitrogen, particularly NO3− represents a stress signal that triggers the activation of antioxidant enzymes to protect the plants against salinity-induced oxidative damage. Furthermore, the source/form of N application can affect not only N-interactions but also the behavior of other nutrients in stress environment. The present review deals with N-salinity relations in plants, particularly glycophytes, emphasizing on N-induced mechanisms which can improve plant adaptation to saline environment. [ABSTRACT FROM AUTHOR]

A field study was conducted to test the potential of 5-year consecutive application of fresh industrial sludge (FIS) and composted industrial sludge (CIS) to restore soil functions at surface (0–15 cm) and subsurface (15–30 cm) of the degraded agricultural land. Sludge amendments increased soil fertility parameters including total organic carbon (TOC), soil available nitrogen (SAN), soil available phosphorus (SAP) and soil available potassium (SAK) at 0–15 cm depth. Soil enzyme activities i.e. dehydrogenase (DHA), β-glucosidase (BGA) and alkaline phosphatase (ALp) were significantly enhanced by FIS and CIS amendments in surface soil. However, urease activity (UA) and acid phosphatase (ACp) were significantly reduced compared to control soil. The results showed that sludge amendments significantly increased microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) at both soil depth, and soil microbial biomass carbon (MBC) only at 0–15 cm depth. Significant changes were also observed in the population of soil culturable microflora (bacteria, fungi and actinomycetes) with CIS amendment in surface soil suggesting persistence of microbial activity owing to the addition of organic matter source. Sludge amendments significantly reduced soil heavy metal concentrations at 0–15 cm depth, and the effect was more pronounced with CIS compared to unamended control soil. Sludge amendments generally had no significant impact on soil heavy metal concentrations in subsoil. Agronomic viability test involving maize was performed to evaluate phytotoxicity of soil solution extract at surface and sub-surface soil. Maize seeds grown in solution extract (0–15 cm) from sludge treated soil showed a significant increase of relative seed germination (RSG), relative root growth (RRG) and germination index (GI). These results suggested that both sludge amendments significantly improved soil properties, however, the CIS amendment was relatively more effective in restoring soil functions and effectively immobilizing wastewater derived heavy metals compared to FIS treatment. [ABSTRACT FROM AUTHOR]

Ecological benefits associated with plant growth-promoting rhizobacteria (PGPR) inoculants offer a promising integrated nutrient management option to counteract plant nitrogen (N) deficiency. We performed field experiments to evaluate the effect of integrated N fertilizer regime involving chemical N fertilizer (CNF) and N-enriched compost (NEC), either alone or combined with selected PGPR ( Pseudomonas aeruginosa) on sunflower seed quality, N use efficiency (NUE) and soil fertility during 2014-2015. We found that integrated N biofertilizer application resulted in significantly higher seed oil concentration, fatty acid composition, and harvest index in both cropping years. Greater effects on N yield efficiency (NYE), N use efficiency (NUE), N physiological efficiency (NPE), and photosynthetic N use efficiency (PNUE) were recorded in nitrogen-enriched compost+PGPR inoculant (NECPI) treatment followed by chemical N fertilizer+PGPR inoculant (CNFPI) treatment. Statistically significant differences were observed in linoleic and linolenic acid, NYE, and NUE for treatment × year interaction, thus, suggesting that the integrated N biofertilizer approach facilitates the efficient N use by sunflower for improving yield and seed quality. Moreover, we also found considerable enhancement of soil N fertility after two consecutive cropping years of sunflower. The enhancement of seed quality, N use efficiencies, and soil N fertility through integrated N biofertilizer application emphasizes the importance of balanced crop N nutrition, ensuring sufficient N supply to sunflower with adequate N balance in soil for the next crop. Overall, combination of PGPR with NEC amendment may optimize N uptake efficiency and reduce N fertilizer losses, which is necessarily required for the sustainable sunflower production. [ABSTRACT FROM AUTHOR]

In many tropical regions, slash-and-burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest. We propose a reclamation strategy for abandoned fields allowing and sustaining re-cultivation. In the dry region of south-western Madagascar, we tested, according to a split-plot design, an alternative selective slash-and-burn cultivation technique coupled with compost amendment on 30-year-old abandoned fields. Corn plants ( Zea mays L.) were grown on four different types of soil amendments: no amendment (control), compost, ashes (as in traditional slash-and-burn cultivation), and compost + ashes additions. Furthermore, two tree cover treatments were applied: 0% tree cover (as in traditional slash-and-burn cultivation) and 50% tree cover (selective slash-and-burn). Both corn growth and soil fertility parameters were monitored during the growing season 2015 up to final harvest. The amendment compost + ashes strongly increased corn yield, which was multiplied by 4-5 in comparison with ashes or compost alone, reaching 1.5 t/ha compared to 0.25 and 0.35 t/ha for ashes and compost, respectively. On control plots, yield was negligible as expected on these degraded soils. Structural equation modeling evidenced that compost and ashes were complementary fertilizing pathways promoting soil fertility through positive effects on soil moisture, pH, organic matter, and microbial activity. Concerning the tree cover treatment, yield was reduced on shaded plots (50% tree cover) compared to sunny plots (0% tree cover) for all soil amendments, except ashes. To conclude, our results provide empirical evidence on the potential of recultivating tropical degraded soils with compost and ashes. This would help mitigating deforestation of the primary forest by increasing lifespan of agricultural lands. [ABSTRACT FROM AUTHOR]

The environmental and economic impacts of chemical fertilizer have encouraged farmers to integrate them with organic materials, an important nutrient management strategy for sustainable agriculture production. In the present study, we conducted field experiments to study the effects of nitrogen enriched compost (NEC) and mineral nitrogen (MN) fertilizer with a selected plant growth promoting rhizobacterial (PGPR) strain, Pseudomonas aeruginosa QS40, on productivity of sunflower and soil fertility. The results demonstrated that integrated application of PGPR with organic-inorganic N significantly increased shoot and root length, leaf area, total chlorophyll, head diameter, fresh biomass, straw-achene yield and N uptake in sunflower compared to unamended control and PGPR alone. The results also showed that integrated N biofertilizer regime enhanced soil microbial biomass, enzymatic activities and soil nitrogen contents. We also observed significant changes in rhizosphere soil pH, abundance of cultivable bacteria and arbuscular mycorrhizae fungi (AMF) root colonization. Treatment and year interaction was significant for dissolved organic carbon (DOC) and microbial biomass carbon (MBC) only. These results suggest that the efficiency of PGPR could be improved with increased availability of labile C substrate resource in NEC amended aridisol. We conclude that the application of NEC fertilizer with efficient PGPR biofertilizer may improve sunflower productivity and soil chemical and biological fertility in nutrient-poor agroecosystems of arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

• Pakistan is only contributing 0.9% to global greenhouse gas (GHG) emissions and is facing devastating floods. • Every governments must turn and listen to science urgently. • The NASA, NSF, and USDA should provide funding to the developing countries for better climate change predictions. [ABSTRACT FROM AUTHOR]

The effect of potassium sulfate (K2SO4) on adaptability of sugarcane to sodium chloride (NaCl) stress was investigated under hydroponic conditions. Two sugarcane cultivars, differing in salinity tolerance, were grown in half strength Johnson's solution at 80 mM NaCl with 0, 2.5 and 5.0 mM potassium (K) as K2SO4. Salinity disturbed above and below-ground dry matter production in both sugarcane cultivars. However, salt sensitive cultivar showed more reduction in shoot dry matter and higher root:shoot ratio compare to the salt tolerant cultivar under. Application of K significantly (p < 0.05) improved dry matter production in both sugarcane cultivars. The concentration of Na was markedly increased with increasing salinity; however, the application of K reduced its uptake, accumulation and distribution in plant tissues. Salinity induced reduction in K concentration, K-uptake, K utilization efficiency (KUE) and K:Na ratio in both sugarcane cultivars was significantly improved with the addition of K to the saline growth medium. [ABSTRACT FROM AUTHOR]

Hexavalent chromium [Cr (VI)], extensively used in different industries, is one of the most toxic heavy metals. The Cr (VI) reducing bacteria could be helpful in decreasing its toxic effects. The present study was conducted to evaluate the potential of Cr (VI) reducing bacteria to improve growth and yield of okra ( Hibiscus esculentus L.) in Cr-contaminated soils. Most of the selected bacterial isolates significantly increased the growth and yield of okra. Maximum response was observed in the plants inoculated with the isolate K12 where plant height, root length, fruit weight and number of fruits per plant increased up to 77.5 percent, 72.6 percent, 1.4 fold and 2.9 fold, respectively. Moreover, inoculation with bacteria caused significant decrease in Cr (VI) concentration in soil and plant parts across all treatments. The maximum decrease of 69.6, 56.1 and 40.0 percent in Cr (VI) concentrations in soil, plant vegetative parts and plant reproductive parts, respectively, was observed in the treatment inoculated with the strain K12. Based on amplification, sequencing and analysis of 16S rDNA sequence, the strain K12 was found belonging to genus Brucella and was designated as Brucella sp. K12. These findings suggest that the strain K12 may serve as a potential bioresource to improve crop production in Cr-contaminated soils. [ABSTRACT FROM AUTHOR]

Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50 µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. [ABSTRACT FROM AUTHOR]

In semi-arid regions, post-restoration vegetation recovery on abandoned agricultural lands often fails due to inherently low organic matter content and poor soil fertility conditions, including phosphorus (P). As such, amending these soils with controlled release P fertilizer, especially with suitable P solubilizing bacteria (PSB) may promote plant growth and productivity by stimulating biological P fertility. To this aim, a pot study was performed to evaluate the agronomic potential of maize and soil biological P pools, using encapsulated (ENRP) and non-encapsulated (NRP) nano-rock phosphate as the P fertilizer source, on reclaimed agricultural soil in the presence and absence of PSB inoculant. The experiment was setup following a 3 × 2 factorial arrangement with four replicates. Without PSB, NRP treatment showed marginal positive effects on plant growth, P nutrition and P use efficiency (PUE) compared to control treatment. Although larger gains with NRP treatment were more noticeable under PSB inoculation, ENRP was the most convenient slow-release P fertilizer, increasing plant growth, P nutrition and grain yield compared to all treatments. Importantly, PSB inoculation with ENRP resulted in significantly higher increase in soil CaCl 2 -P (8.91 mg P kg soil−1), citrate-P (26.98 mg P kg soil−1), enzyme-P (18.98 mg P kg soil−1), resin-P (11.41 mg P kg soil−1), and microbial-P (18.94 mg P kg soil−1), when compared to all treatment combinations. Although a decrease in soil HCl-P content was observed with both types of P fertilizer, significant differences were found only with PSB inoculation. A significant increase in soil biological P pools could be due to the higher specific area and crystalline structure of nano materials, providing increased number of active sites for PSB activity in the presence of biobased encapsulated shell. Furthermore, the increase in PSB abundance, higher root carboxylate secretions, and decreased rhizosphere pH in response to nano-structured P fertilizer, implies greater extension of rhizosphere promoting greater P mobilization and/or solubilization, particularly under PSB inoculated conditions. We conclude that cropping potential of abandoned agricultural lands can be enhanced by the use of nano-rock phosphate in combination with PSB inoculant, establishing a favorable micro-environment for higher plant growth and biochemical P fertility • A pot study was performed on recently reclaimed abandoned agricultural soil. • ENRP fertilizer is a highly promising controlled release P fertilizer than NRP. • ENRP-PSB fertilization efficiently establishes maize and improves productivity. • Nano-P fertilization extends rhizosphere and improves soil P biological pools. • ENRP-PSB is sustainable approach to enhance productive capacity of degraded soils. [ABSTRACT FROM AUTHOR]

Plant Growth Promoting Rhizobacteria (PGPR), whose role is still underestimated, plays an important (or perhaps essential) role in improving plant growth. The comprehensive understanding of bacterial plant growth promoting mechanism helps to get sustainable agriculture production under biotic and abiotic stresses. In the present study, plant growth promoting (PGP) bacterial strain Pseudomonas aeruginosa having maximum inhibitory concentration of 1500mgkg−1 against Zn was isolated from arable land, irrigated with industrial effluent and evaluated to determine it bioremediation potential. The study was mainly focused on plant biomass production, nutrient uptake and oxidative stress tolerance in relation to the activities of antioxidative enzymes and the content of non-enzymatic antioxidants. The oxidative stress tolerance was measured by estimating the MDA accumulation as well as H2O2 production in wheat plants under Zn (1000mgkg−1) stress and inoculation of soil with Zn resistant Pseudomonas aeruginosa. Zn in rooting medium reduced the plant growth, leaf photosynthetic pigments as well as uptake of N and P. However, content of MDA and H2O2 increased at higher concentration of Zn. Inoculation of P. aeruginosa improved the uptake of P and N in wheat plants with an increase in leaf chlorophyll, total soluble protein and plant biomass production. Analysis of plant root and shoot disclosed that Zn concentration was significantly lowered in P. aeruginosa inoculated zinc stressed plants as compare to the plants grown under Zn stress only. The amelioration of adverse effects of Zn stress on biomass production due to P. aeruginosa inoculation was related with enhanced antioxidative enzyme activities (SOD, POD and CAT), and the contents of non-enzymatic components such as ascorbic acid and total phenolics (TPC) as compare to Zn-treated plants. The up-gradation in antioxidative defense mechanism, resulted a reduction in H2O2 and MDA content due to the scavenging of ROS by antioxidants. It was concluded that P. aeruginosa is an ideal candidate for bioremediation and wheat growth promotion against Zn-induced oxidative stress by improving the availability of necessary nutrient, eliciting antioxidant defense system as well as by lowering the Zn metal uptake. [Copyright &y& Elsevier]