Abstract The need to transition to more sustainable agriculture that is adaptable to environmental challenges, reducing dependence on chemical fertilizers and minimizing environmental impact, ...represents the new paradigm of the moment. In this scenario, studies with the adoption of bioinputs in corn cultivation emerge as a viable option for the sustainability of agricultural activity. Therefore, the objective was to evaluate the effect of doses of neem vegetable cake on the yield components of corn crops. An experimental design was used of randomized blocks was used, consisting of four doses of neem vegetable rendering (3 kg ha-1, 6 kg ha-1, 9 kg ha-1 and 12 kg ha-1) and a treatment control without the presence of organic fertilizer. The result indicates the presence of a significant effect of treatments with the application of neem cake on the main components of corn yield, including grain productivity, suggesting that the high carbon content present in the organic product can induce phytochemical effects and biological changes. in the soil, making it more productive. It was found that, when administering the maximum experimental dose, compared to the control group, there was a significant effect (p≤0.01) of 21.3% on grain productivity, jumping from 2,140 kg ha -1, when did not apply organic fertilizer, to 2,596 kg ha-1 with the application of 12 kg of neem cake per hectare. It is noted that the increase in grain productivity was in the proportion of 38 kg ha-1 of corn for each kilo of neem cake applied. To facilitate interpretation and decision-making, an analysis of the economic viability of neem cake for rainfed corn was also determined, also identifying the maximum experimental dose of 12 kg ha-1, as the most economically viable, providing an increase in profit of around R$ 119.92 per hectare, in relation to the control.
Resumo A necessidade de transitar para uma agricultura mais sustentável e adaptável aos desafios ambientais, com redução da dependência de fertilizantes químicos e minimização do impacto ambiental, representa o novo paradigma do momento. Nesse cenário, estudos com a adoção de bioinsumos na cultura do milho emergem como uma opção viável para a sustentabilidade da atividade agrícola. Portanto, objetivou-se avaliar o efeito de doses de torta vegetal de neem nos componentes de rendimento da cultura do milho. Utilizou-se um delineamento experimental de blocos casualizados constituídos pelas quatro doses da torta vegetal de neem (3 kg ha-1, 6 kg ha-1, 9 kg ha-1 e 12 kg ha-1) e um tratamento testemunha sem a presença do adubo orgânico. O resultado indica a presença de um efeito significativo dos tratamentos com aplicação da torta de neem sobre os principais componentes de rendimento do milho, incluindo a produtividade dos grãos, sugerindo que o alto teor de carbono presente no produto orgânico pode induzir efeitos fitoquímicos e mudanças biológicas no solo, tornando-o mais produtivo. Verificou-se que, ao administrar a dose máxima experimental, em comparação com o grupo de controle, houve um efeito significativo (p≤0,01) de 21,3% na produtividade dos grãos, saltando de 2.140 kg ha -1, quando não aplicou o adubo orgânico, para 2.596 kg ha-1 com a aplicação de 12 kg da torta de neem por hectare. Nota-se que o incremento na produtividade dos grãos foi na proporção de 38 kg ha-1 de milho para cada quilo de torta de neem aplicado. Para facilitar a interpretação e tomada de decisão, determinou-se também a análise de viabilidade econômica da torta de neem para a cultura do milho cultivado em sequeiro, identificando também a dose máxima experimental de 12 kg ha-1, como a mais viável economicamente, proporcionando um incremento no lucro na ordem de R$ 119,92 por hectare, em relação a testemunha.
Soil amendments are used extensively to remediate soils contaminated with heavy metals. However, the effects of soil amendments on heavy metal bioavailability, plant yield, and bacterial community ...structure in tropical farmland soils remain largely unknown. In the present study, seaweed organic fertilizer (S), apatite (A), biochar (B), and seaweed organic fertilizer-apatite-biochar mixtures (SAB) were applied at different rates to assess their influence on cadmium (Cd), lead (Pb), and chromium (Cr) bioavailability in contaminated farmland soils, using different component ratios and doses in maize field plots, and maize yield. Effects on soil bacterial community structure were also evaluated based on high-throughput sequencing. Following addition of 2 % S + A + B combined amendment at a ratio of 1:0.5:1.5 (2%S1A0.5B1.5), soil pH and electrical conductivity (EC) were elevated, and bioavailable Cd, Pb, and Cr concentrations were reduced in potted soils, leading to higher heavy metal immobilization. Under field conditions, soil pH, EC, organic matter, ammonium‑nitrogen, available phosphorus, available potassium, and crop productivity were all increased considerably, whereas soil Cd and Cr bioavailability were lower in the combined amendment treatments than in the control treatments. Particularly, application of a 2.49 t·ha−1 combined amendment (0.83 t·ha−1 S + 0.41 t·ha−1A + 1.25 t·ha−1B,1:0.5:1.5) decreased Cd, Pb, and Cr concentrations in maize grain by 68.9 %, 68.9 %, and 65.7 %, respectively. Species abundance and evenness in bacterial communities increased in field soils subjected to combined amendments, with shifts in community structure and function mostly driven by changes in soil pH, organic matter content, and nutrient availability. Overall, the results suggest that 1.5%S1A0.5B1.5 is the optimal treatment for remediating heavy metal co-contaminated soil, and thereby, improving maize yield and quality. Combined organic and inorganic amendments achieve high remediation efficiency, mainly by improving chemical properties, reducing heavy metal bioavailability, and altering bacterial community structure and function in heavy metal contaminated farmland soils.
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•Cd, Pb, and Cr co-contaminated soils remediated with combined amendments.•Combined amendments improved soil and altered soil bacterial community structure.•Maize plant growth enhanced in co-contaminated soils receiving combined amendments.
SUMMARY
In higher plants, the generation and release of viable pollen from anthers is vital for double fertilization and the initiation of seed development. Thus, the characterization of genes ...related to pollen development and anther dehiscence in plants is of great significance. The F‐box protein COI1 plays a crucial role in the jasmonate (JA) signaling pathway and interacts with many JAZ family proteins in the presence of jasmonoyl‐isoleucine (JA‐Ile) or coronatine (COR). The mutation of AtCOI1 in Arabidopsis leads to defective anther dehiscence and male sterility (MS), although COI has not been shown to affect fertility in Zea mays (maize). Here we identified two genes, ZmCOI2a and ZmCOI2b, that redundantly regulate gametophytic male fertility. Both ZmCOI2a and ZmCOI2b are highly homologous and constitutively expressed in all tissues tested. Subcellular localization revealed that ZmCOI2a and ZmCOI2b were located in the nucleus. The coi2a coi2b double mutant, generated by CRISPR/Cas9, had non‐dehiscent anthers, delayed anther development and MS. In addition, coi2a coi2b male gametes could not be transmitted to the next generation because of severe defects in pollen germination. The JA content of coi2a coi2b anthers was unaltered compared with those of the wild type, and the exogenous application of JA could not rescue the fertility defects of coi2a coi2b. Transcriptome analysis showed that the expression of genes involving the JA signaling transduction pathway, including ZmJAZ3, ZmJAZ4, ZmJAZ5 and ZmJAZ15, was affected in coi2a coi2b. However, yeast two‐hybrid assays showed that ZmJAZs interacted with ZmCOI1s, but not with ZmCOI2s. In conclusion, ZmCOI2a and ZmCOI2b redundantly regulate anther dehiscence and gametophytic male fertility in maize.
Significance Statement
The F‐box protein COI1 plays a crucial role in the jasmonate signaling pathway. However, the function of COI in maize has remained elusive. Here, we identified two genes, ZmCOI2a and ZmCOI2b, that redundantly regulate anther dehiscence, filament elongation and gametophytic male fertility in maize.
It is widely known that cobalt (Co) stress adversely affects plant growth and biomass accumulation, posing serious threats to crop production and food security. Nanotechnology is an emerging field in ...crop sciences for its potential in improving crop production and mitigating various stresses. Although there have been several studies reporting the toxic effects of zinc oxide nanoparticles (ZnO NPs) on different crops, their role in ameliorating heavy metal toxicity are still poorly understood. This study aimed to investigate the beneficial effects of seed priming with ZnO NPs in mitigating the phytotoxicity induced by Co stress. Our results demonstrated that ZnO NPs significantly improved the plant growth, biomass, and photosynthetic machinery in maize under Co stress. The NPs priming reduced ROS and MDA accumulations in maize shoots. More importantly, ZnO NPs alleviated the toxic effects of Co by decreasing its uptake and conferred stability to plant ultra-cellular structures and photosynthetic apparatus. Furthermore, a higher accumulation of nutrient content and antioxidant enzymes were found in NPs-primed seedlings. Collectively, we provide first evidence to demonstrate the alleviation of Co toxicity via ZnO NPs seed priming in maize, thus, illustrating the potential role of ZnO NPs to be applied as a stress mitigation agent for the crops grown in Co contaminated areas to enhance crop growth and yield.
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•ZnO NPs localized in seed labeled with Zinpyr-1 under confocal microscopy.•ZnO NPs increased seed zinc contents and enhanced nutrient uptake under Co stress.•ZnO NPs reduced oxidative damage and improved plant antioxidant defense system.•ZnO NPs improved plant photosynthetic efficiency and biomass accumulation.•ZnO NPs protected stomatal and ultra-cellular structure of plant under Co stress.
Leaf area and its longevity are the key factors driving dry matter accumulation and yield formation in maize (Zea mays. L). Both factors are influenced by cultivation management measures. The ...objective of this study was to utilize a quantitative framework to better understand the contribution of leaf area and longevity to leaf area duration (LAD) and yield in maize plants at varying plant densities and nitrogen application rates. A two-year field experiment was conducted using a factorial combination of two plant densities and four nitrogen levels. Leaf area and longevity were measured at each leaf position in two different maize cultivars. We calculated the LAD at the single-leaf, individual-plant, and whole-population scales and quantitatively analyzed the contribution of leaf area and longevity to LAD. The results showed that in the upper leaves, leaf area had a larger proportional contribution to LAD (54.1–95.7%), whereas in the lower leaves, leaf longevity contributed more to LAD (51.8–74.1%). Both were greatly affected by variations in plant density and nitrogen application. At the individual-plant scale, the proportional contribution of leaf area to LAD (57.3%) was similar to that of leaf longevity (57.2%); at the whole-population scale, leaf area accounted for a larger contribution to LAD (87.0%). The increase in LAD (which integrating increases in leaf area and longevity) was positively associated with an increase in dry matter at maturity and grain yield. Yield gain was achieved by reasonable increases in density and nitrogen fertilizer application to promote LAD. The quantitative evaluation of leaf area and longevity described in this study provides a theoretical basis for increasing maize yield under increased plant density and nitrogen input conditions.
•Density and nitrogen affect upper leaves’ area and lower longevity of canopy.•Leaf area and longevity contribute equally to LAD variations at individual scale.•Contribution of leaf area to LAD variation was greater at population scale.•Nitrogen application offset the negative effects of increasing plant density partly.
Biochar is widely used as a soil amendment to challenge climate change through restraining greenhouse gas production and increasing soil C sink in cropland soils, yet its effect was not studied well ...under drip irrigation with mulch. A two-year field experiment was conducted to investigate the impact of corn residue-derived biochar amendments on greenhouse gases (GHG), soil organic carbon (SOC), and global warming potential (GWP) on sandy loam soil in Inner Mongolia, China. Biochar application rates of 0 (B0, control), 15 (B15), 30 (B30), and 45 (B45) t ha−1 were broadcasted onto the soil surface, and then mixed into 30-cm soil depth at the first crop growing season to a film-mulched and drip-irrigated corn production. Soil emissions of CO2, N2O, and CH4 were measured using a closed static chamber approach. Compared to control plots, biochar amendments reduced total CO2 emission by 18–25% at the first growing season, and 19–41% at the second growing season. The highest and lowest CH4 emissions were from B45 and B15 in the first year, and B45 and B30 in the second year, respectively. Relative to the control, B15 and B30 reduced CH4 emission by 124% and 132% as averaged over 2-yr. With biochar amendments, total N2O emission was decreased by 71–110% and 39–47% in the first and second year. Among these biochar amendments, B30 was the best amendment limiting the GWP of N2O and CH4 in any of the two years. B30 and B45 significantly increased SOC sequestration in the top 15-cm depth by 19% and 37% in the first growing season, respectively, and by 12% and 15% in the second growing season. Biochar amendment B30 also significantly increased corn yields. Biochar shows the greatest potential to mitigate greenhouse gas emissions and increase soil C sequestration. The greatest reductions with biochar application 30 t ha−1 in corn.
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•Corn residue-derived biochar applied into corn production reduced CO2 and N2O emissions.•CH4 emission was decreased by 132% when biochar amendment (30 t ha−1) was used.•Biochar amendment (30 t ha−1) increased SOC sequestration in upper 15-cm depth by 16%.•Corn yield increased by 7.4% for biochar addition (30 t h ha−1) over 2-yr.•Biochar application (30 t ha−1) was suitable for corn with drip-irrigation and film mulch.
•Plant height, stem physical strength, and lignin content is closely related to the lodging resistance of maize.•Mepiquat chloride, a potential growth retardant reduced the plant height, ear height ...and lowered the gravity center of high-density maize.•Mepiquat chloride significantly improved the stem physical strength and accumulation of lignin content of maize.•Mepiquat chloride reduced the lodging rate, improved yield components and increased the grain yield of summer maize.•The best concentration of seed dressing with mepiquat chloride was 2.5 g kg−1.
Lodging is a major adversity which limits maize grain yields and quality, especially under dense population. The present study was conducted to determine the efficacy of mepiquat chloride, a potential anti-gibberellic plant growth retardant on plant height, the physical strength of stem, lignin content and its relationship with lodging resistant in maize crop. Maize seeds were dressed with mepiquat chloride at the rate of 0 (MC0), 2.0 (MC1), 2.5 (MC2), and 3.0 (MC3) g kg−1 during 2015–2016. Our results showed that mepiquat chloride treatments enhanced the culm physical strength, as revealed by enhanced rind puncture strength and stalk bending strength, increased dry weight per cm, stem diameter, and lignin accumulation resulting in strong lodging resistance. A significant and negative correlation was detected between stalk bending and rind puncture strength with lodging rate. Moreover, the lodging rate, plant height, internodes length and gravity center height were significantly reduced following a dose-response trend, and MC2 and MC3 treatments resulted in relatively shorter plants, compared to control treatment. In addition, the grain yield, lignin contents and activities of lignin-related enzymes were enhanced by mepiquat chloride, and the MC2 (2.5 g kg−1) treatment showed the best effect of all treatments. The correlation analysis revealed that lignin accumulation was negatively and significantly correlated with lodging rate of the maize crop. Our results imply that plant height obviously, as well as the culm physical strength and lignin are closely associated with the lodging resistance in maize, and the decreased plant height, enhanced culm morphological characteristics and lignin content could strengthen the resistance of crops to lodging.
Biodiesel production from corn oil: A review Veljković, Vlada B.; Biberdžić, Milan O.; Banković-Ilić, Ivana B. ...
Renewable & sustainable energy reviews,
08/2018, Letnik:
91
Journal Article
Recenzirano
This paper deals with biodiesel production from corn oil as a feedstock via the transesterification and esterification reactions. To date, corn oil has not been considered a viable biodiesel ...feedstock because of its high edible value and relatively high price, but some industrial corn processing co-products, such as corn germ and dried distillers grains with solubles (DDGS), have potential for this application after the extraction of corn distillers oil (CDO). Here, after brief discussion of the issues related to corn botany, cultivation, and use, as well as the corn germ and oil composition, properties and use, the methods of corn processing for germ and DDGS recovery are presented. In addition, the mechanical and solvent extraction techniques for oil recovery from whole ground corn kernels, germs, and DDGS are considered. Furthermore, biodiesel production from corn oil, waste frying corn oil, and CDO is critically analyzed. It is expected that further investigation will be directed toward developing simpler, more effective and energy-saving technologies for biodiesel production from corn oil-based feedstocks, especially from CDO. The integration of biodiesel production directly into corn-based ethanol production will advance the overall economy of industrial plants. Furthermore, the fuel properties, performances and exhaust gas emissions of corn-based biodiesel and its blends with diesel fuel are discussed, taking into account the biodiesel quality standards. Finally, issues related to the environmental and socio-economic impacts of corn-based biodiesel production and use are also tackled.
•Oily co–products of industrial corn processing are promising biodiesel feedstocks.•“Green” oil extraction methods will improve corn oil recovery.•Simpler, more efficient and energy–saving corn-based biodiesel technology is needed.•The integrated reactor/separation process of biodiesel production is more efficient.•Biodiesel production can be integrated in the corn-based ethanol production.
The effects of polystyrene nanoplastics (PSNPs) on the physiological and molecular metabolism of corn seedlings were examined by treating corn (Zea mays L.) seedlings with 100, 300, and 500 nm ...diameter PSNPs and examining plant photosynthetic characteristics, antioxidant enzyme systems, and molecular metabolism. After 15 days of exposure to PSNPs with different particle sizes (50 mg·L−1), the photosynthetic characteristics of the plant remained stable, and the maximum photochemical quantum yield (Fv/Fm) and non-photochemical quenching coefficient (NPQ) had no significant effects. The root microstructure was damaged and the antioxidant enzyme system was activated, and the content of malondialdehyde (MDA) was significantly increased by 2.25–4.50-fold. In addition, 100 nm and 300 nm PSNPs exposure caused root superoxide dismutase (SOD) activity to increase 1.28-fold and 1.53-fold, and glutathione-peroxidase (GSH-PX) activity increased 1.30-fold and 1.58-fold. Non-targeted metabolomics analysis identified a total of 304 metabolites. Exposure to 100, 300, and 500 nm PSNPs led to the production of 85 (upregulated: 85, downregulated: 0), 73 (upregulated: 73, downregulated: 0), and 86 (upregulated: 84, downregulated: 2) differentially expressed metabolites, respectively, in the plant roots. Co-expressed differential metabolites accounted for 38.2% of the metabolites and indicated a metabolic imbalance primarily in organic acids and derivatives in the root system. The most significant enrichment pathways were those of alanine, aspartate, and glutamate metabolism. Overall, exposure to PSNPs of different particle sizes activated the root antioxidant enzyme system and interfered with plant basic metabolism. The alanine, aspartate, and glutamate metabolic pathways appear to be closely related to plant mechanisms for tolerance/detoxification of PSNPs.
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•Exposure to PSNPs activated the root antioxidant enzyme system.•PSNPs mainly interfered with the normal metabolism of organic acids and derivatives.•PSNPs cause alanine, aspartate, and glutamate metabolic high response.
Root exudates play an essential role in helping plants to cope with abiotic stress. However, the modulation of root exudation profiles under multiple stress conditions is still poorly understood. ...Using targeted and untargeted metabolomics, here we tested the effect of drought, heat stress, and their combination on maize root exudates, also considering the differences that might exist between root types (seminal and primary) and root zones (apical and sub-apical). In addition, we built an analytical framework that relates the root exudation profile with the rhizosphere bacterial community, enabling us to dissect the interactions between specific root exudates and bacterial taxa. The composition of root exudates undergoes distinct modulation according to the single or combined stress and to the root zone, but not according to the root type. In addition, we found that stress-specific exudates can influence the relative abundance of specific bacterial taxa, some of which are known to be beneficial microorganisms. Our results contribute to the understanding of plant-soil interactions under the influence of abiotic stressors, which is key in paving the way towards an increased resilience to abiotic stresses, representing a powerful tool to craft the next generation of agricultural practices.
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•Drought, heat, and their combination have a specific influence on root exudation.•The combination of stresses influences exudates differently from the single stresses.•Changes in root exudation are associated with changes of specific microbial taxa.
