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1.
Philos Trans A Math Phys Eng Sci ; 378(2183): 20200188, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32981442

RESUMO

We suggest that the unprecedented and unintended decrease of emissions of air pollutants during the COVID-19 lock-down in 2020 could lead to declining seasonal ozone concentrations and positive impacts on crop yields. An initial assessment of the potential effects of COVID-19 emission reductions was made using a set of six scenarios that variously assumed annual European and global emission reductions of 30% and 50% for the energy, industry, road transport and international shipping sectors, and 80% for the aviation sector. The greatest ozone reductions during the growing season reached up to 12 ppb over crop growing regions in Asia and up to 6 ppb in North America and Europe for the 50% global reduction scenario. In Europe, ozone responses are more sensitive to emission declines in other continents, international shipping and aviation than to emissions changes within Europe. We demonstrate that for wheat the overall magnitude of ozone precursor emission changes could lead to yield improvements between 2% and 8%. The expected magnitude of ozone precursor emission reductions during the Northern Hemisphere growing season in 2020 presents an opportunity to test and improve crop models and experimentally based exposure response relationships of ozone impacts on crops, under real-world conditions. This article is part of a discussion meeting issue 'Air quality, past present and future'.


Assuntos
Poluição do Ar/análise , Betacoronavirus , Infecções por Coronavirus/epidemiologia , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Ozônio/análise , Pandemias , Pneumonia Viral/epidemiologia , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/prevenção & controle , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Europa (Continente) , Humanos , Modelos Biológicos , Dióxido de Nitrogênio/análise , Dióxido de Nitrogênio/toxicidade , Ozônio/toxicidade , Medição de Risco , Estações do Ano
2.
PLoS One ; 15(8): e0238396, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866180

RESUMO

The effect of different management techniques for plant control in the vineyard were compared in the present work, focusing on plant diversity preservation and management efficacy in a two-year experiment on vineyard row weed community. Biomass-fueled flame weeding (with two intensities) was applied as an innovative plant control technique in contrast to tillage and mowing practices. The results showed that flaming was comparable to tillage regarding weed control effectiveness, and was more efficient than mowing. However, species number and functional evenness were not substantially modified by changing the applied management technique. Functional trait analysis demonstrated that row management significantly affected the frequency of annual plants, plant height, root depth index, and the occurrence of plants with storage organs. As for species composition, meaningful differences were found: only the two flaming treatments (i.e. gentle vs intense) and the gentle flaming vs mowing had consistent species composition. Flame wedding showed some potential benefits in plant control in the vineyard by favouring small plant and controlling overall weed abundance. On the other hand, flaming favoured plant species with asexual reproduction, with a potential negative impact on weed-vine competition and species persistence in the vineyard. Further studies are required to investigate such contrasting aspects, also considering other weed control techniques (e.g. cover-crops), considering a sustainable perspective of an herbicide-free environment.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Plantas Daninhas/efeitos dos fármacos , Poaceae/crescimento & desenvolvimento , Controle de Plantas Daninhas/métodos , Agricultura/métodos , Biodiversidade , Biomassa , Produtos Agrícolas/efeitos dos fármacos , Fazendas , Herbicidas/farmacologia , Plantas/efeitos dos fármacos , Poaceae/efeitos dos fármacos
3.
Chemosphere ; 260: 127578, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32683024

RESUMO

Micro- and nano-plastics have widely been recognized as major global environmental problem due to its widespread use and inadequate waste management. The emergence of these plastic pollutants in agroecosystem is a legitimate ecotoxicological concerns for food web exchanges. In agriculture, micro/nano plastics are originated from a variety of different agricultural management practices, such as the use of compost, sewage sludge and mulching. A range of soil properties and plant traits are affected by their presence. With the increase of plastic debris, these pollutant materials have now begun to demonstrate serious implications for key soil ecosystem functions, such as soil microbial activity and nutrient cycling. Nitrogen (N) cycle is key predictor of ecological stability and management in terrestrial ecosystem. In this review, we evaluate ecological risks associated with micro-nano plastic for soil-plant system. We also discuss the consequence of plastic pollutants, either positive or negative, on soil microbial activities. In addition, we systematically summarize both direct and hypothesized implications for N cycling in agroecosystem. We conclude that soil N transformation had showed varied effects resulting from different types and sizes of plastic polymers present in soil. While mixed effects of microplastic pollution on plant growth and yield have been observed, biodegradable plastics have appeared to pose greater risk for plant growth compared to chemical plastic polymers.


Assuntos
Microplásticos/toxicidade , Nitrogênio/metabolismo , Plantas/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo , Agricultura , Produtos Agrícolas/efeitos dos fármacos , Ecossistema , Ecotoxicologia , Poluição Ambiental , Nanoestruturas , Esgotos , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
4.
Chemosphere ; 258: 127350, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554012

RESUMO

The adverse effects of glyphosate herbicide on plants are well recognised, however, potential hormetic effects have not been well studied. This study aimed to use tomato as a model organism to explore the potential hormetic effects of glyphosate in water (0-30 mg L-1) and in compost soil (0-30 mg kg-1). The growth-promoting effects of glyphosate at concentrations of 0.03-1 mg L-1 in water or 0.03-1 mg kg-1 in compost were demonstrated in tomato for the first time. These hormetic effects were manifest as increased hypocotyl and radicle growth of seedlings germinated on paper towel soaked in glyphosate solution and also in crops which had been sprayed with glyphosate. Increased rates of photosynthesis (up to 2-fold) were observed in 4-week old crops when seeds were sown in compost amended with glyphosate and also when leaves were sprayed with glyphosate. The examination of chloroplast morphology using transmission electron microscopy revealed that the hormetic effects were associated with elongation of chloroplasts, possibly due to lateral expansion of thylakoid grana.


Assuntos
Germinação/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Lycopersicon esculentum/fisiologia , Cloroplastos/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Glicina/toxicidade , Hormese/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos , Solo
5.
PLoS One ; 15(6): e0234390, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32525917

RESUMO

Fungicide use in the United States to manage soybean diseases has increased in recent years. The ability of fungicides to reduce disease-associated yield losses varies greatly depending on multiple factors. Nonetheless, historical data are useful to understand the broad sense and long-term trends related to fungicide use practices. In the current study, the relationship between estimated soybean yield losses due to selected foliar diseases and foliar fungicide use was investigated using annual data from 28 soybean growing states over the period of 2005 to 2015. For national and regional (southern and northern United States) scale data, mixed effects modeling was performed considering fungicide use as a fixed and state and year as random factors to generate generalized R2 values for marginal (R2GLMM(m); contains only fixed effects) and conditional (R2GLMM(c); contains fixed and random effects) models. Similar analyses were performed considering soybean production data to see how fungicide use affected production. Analyses at both national and regional scales showed that R2GLMM(m) values were significantly smaller compared to R2GLMM(c) values. The large difference between R2 values for conditional and marginal models indicated that the variation of yield loss as well as production were predominantly explained by the state and year rather than the fungicide use, revealing the general lack of fit between fungicide use and yield loss/production at national and regional scales. Therefore, regression models were fitted across states and years to examine their importance in combination with fungicide use on yield loss or yield. In the majority of cases, the relationship was nonsignificant. However, the relationship between soybean yield and fungicide use was significant and positive for majority of the years in the study. Results suggest that foliar fungicides conferred yield benefits in most of the years in the study. Furthermore, the year-dependent usefulness of foliar fungicides in mitigating soybean yield losses suggested the possible influence of temporally fluctuating abiotic factors on the effectiveness of foliar fungicides and/or target disease occurrence and associated loss magnitudes.


Assuntos
Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Soja/crescimento & desenvolvimento , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Fungos/efeitos dos fármacos , Fungos/patogenicidade , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/provisão & distribução , Modelos Biológicos , Doenças das Plantas/microbiologia , Folhas de Planta/efeitos dos fármacos , Soja/efeitos dos fármacos , Soja/microbiologia , Análise Espaço-Temporal , Estados Unidos
6.
Proc Natl Acad Sci U S A ; 117(22): 12017-12028, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32434917

RESUMO

Synthetic chemical elicitors, so called plant strengtheners, can protect plants from pests and pathogens. Most plant strengtheners act by modifying defense signaling pathways, and little is known about other mechanisms by which they may increase plant resistance. Moreover, whether plant strengtheners that enhance insect resistance actually enhance crop yields is often unclear. Here, we uncover how a mechanism by which 4-fluorophenoxyacetic acid (4-FPA) protects cereals from piercing-sucking insects and thereby increases rice yield in the field. Four-FPA does not stimulate hormonal signaling, but modulates the production of peroxidases, H2O2, and flavonoids and directly triggers the formation of flavonoid polymers. The increased deposition of phenolic polymers in rice parenchyma cells of 4-FPA-treated plants is associated with a decreased capacity of the white-backed planthopper (WBPH) Sogatella furcifera to reach the plant phloem. We demonstrate that application of 4-PFA in the field enhances rice yield by reducing the abundance of, and damage caused by, insect pests. We demonstrate that 4-FPA also increases the resistance of other major cereals such as wheat and barley to piercing-sucking insect pests. This study unravels a mode of action by which plant strengtheners can suppress herbivores and increase crop yield. We postulate that this represents a conserved defense mechanism of plants against piercing-sucking insect pests, at least in cereals.


Assuntos
Acetatos/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Flavonoides , Hemípteros , Imunidade Vegetal/efeitos dos fármacos , Animais , Bioensaio , Produtos Agrícolas/efeitos dos fármacos , Flavonoides/análise , Flavonoides/metabolismo , Herbivoria , Hordeum/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/metabolismo , Oryza/efeitos dos fármacos , Peroxidases/análise , Peroxidases/metabolismo , Controle de Pragas/métodos , Folhas de Planta/química , Triticum/efeitos dos fármacos
7.
Ecotoxicol Environ Saf ; 200: 110748, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32470678

RESUMO

Cadmium (Cd) is an inauspicious abiotic traction that not only influences crop productivity and its growth parameters, but also has adverse effects on human health if these crops are consumed. Among crops, leafy vegetables which are the good source of mineral and vitamins accumulate more Cd than other vegetables. It is thus important to study photosynthetic variables, amino acid composition, and ultrastructural localization of Cd differences in response to Cd accumulation between two low and high Cd accumulating Brassica rapa ssp. chinensis L. (pak choi) cultivars, differing in Cd accumulation ability. Elevated Cd concentrations significantly lowered plant growth rate, biomass, leaf gas exchange and concentrations of amino acids collated to respective controls of both cultivars. Electron microscopy indicated that the impact of high Cd level on ultrastructure of leaf cells was associated to affecting cell functionalities, i.e. irregular cell wall, withdrawal of cell membrane, and chloroplast structure which has negative impact on photosynthetic activities, thus causing considerable plant growth suppression. Damage in root cells were observed in the form of enlargement of vacuole. The energy dispersive micro X-ray spectroscopy of both cultivars leaves indicated that cellular structure exhibited exudates of Cd-dense material. Ultrastructural damages and phytotoxicity were more pronounced in high accumulator cultivar as compared to the low accumulator cultivar. These findings are useful in determining the mechanisms of differential Cd-tolerance among cultivars with different Cd tolerance abilities at cellular level.


Assuntos
Brassica rapa/efeitos dos fármacos , Brassica rapa/metabolismo , Cádmio/toxicidade , Aminoácidos/análise , Biomassa , Brassica rapa/crescimento & desenvolvimento , Brassica rapa/ultraestrutura , Cádmio/farmacocinética , Parede Celular/efeitos dos fármacos , Parede Celular/ultraestrutura , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Humanos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura
8.
Ecotoxicol Environ Saf ; 196: 110549, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32251953

RESUMO

Chemicals used to assure agricultural production and the feasibility of planting sites often end up in bodies of water used for crop irrigation. In a pot study, we investigated the consequences associated with the irrigation of maize with water contaminated by ciprofloxacin (Cipro; 0, 0.2, 0.8, 1.4 and 2.0 µg l-1) and/or glyphosate (0, 5, 25 and 50 mg l-1) on yields and food safety. Glyphosate in concentrations ≥25 mg l-1 prevented plant establishment, regardless of Cipro presence. Evaluations made at the V5 stage of plants reveal that Cipro concentrations ≥0.8 µg l-1 and glyphosate decreased photosynthesis and induced changes in leaf anatomy and stem biophysical properties that may contribute to decreased kernel yields. When those chemicals were applied together, kernel yield reductions were accentuated, evidencing their interactive effects. Irrigation with contaminated water resulted in accumulations of Cipro and glyphosate (as well as its metabolite, aminomethylphosphonic acid) in plant tissues. Accumulation of these chemicals in plant tissues such as leaves and kernels is a problem, since they are used to feed animals and humans. Moreover, these chemicals are of potential toxicological concern, principally due to residue accumulations in the food chain. Specially, the antibiotic residue accumulations in maize tissues can assist the induction of antibiotic resistance in dangerous bacteria. Therefore, we point out the urgency of monitoring the quality of water used for crop irrigation to avoid economic and food-quality losses.


Assuntos
Antibacterianos/toxicidade , Ciprofloxacino/toxicidade , Glicina/análogos & derivados , Poluentes Químicos da Água/toxicidade , Zea mays/efeitos dos fármacos , Irrigação Agrícola , Animais , Antibacterianos/farmacocinética , Ciprofloxacino/farmacocinética , Produtos Agrícolas/anatomia & histologia , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/economia , Inocuidade dos Alimentos , Glicina/farmacocinética , Glicina/toxicidade , Humanos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/anatomia & histologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Poluentes Químicos da Água/farmacocinética , Zea mays/anatomia & histologia , Zea mays/metabolismo
9.
Nat Commun ; 11(1): 1608, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32231209

RESUMO

The emerging resistance of crop pathogens to fungicides poses a challenge to food security and compels discovery of new antifungal compounds. Here, we show that mono-alkyl lipophilic cations (MALCs) inhibit oxidative phosphorylation by affecting NADH oxidation in the plant pathogens Zymoseptoria tritici, Ustilago maydis and Magnaporthe oryzae. One of these MALCs, consisting of a dimethylsulfonium moiety and a long alkyl chain (C18-SMe2+), also induces production of reactive oxygen species at the level of respiratory complex I, thus triggering fungal apoptosis. In addition, C18-SMe2+ activates innate plant defense. This multiple activity effectively protects cereals against Septoria tritici blotch and rice blast disease. C18-SMe2+ has low toxicity in Daphnia magna, and is not mutagenic or phytotoxic. Thus, MALCs hold potential as effective and non-toxic crop fungicides.


Assuntos
Cátions/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Substâncias Protetoras/farmacologia , Animais , Ascomicetos/efeitos dos fármacos , Cátions/química , Daphnia/efeitos dos fármacos , Descoberta de Drogas , Grão Comestível/microbiologia , Fibroblastos/efeitos dos fármacos , Fungicidas Industriais/química , Humanos , Mitocôndrias/efeitos dos fármacos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Substâncias Protetoras/química , Triticum/microbiologia , Ustilago/efeitos dos fármacos
10.
Environ Sci Pollut Res Int ; 27(15): 17692-17705, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32246421

RESUMO

Weeds are a major constraint to crop production and a barrier to human efforts to meet the ever-rising global demand for food, fibre and fuel. Managing weeds solely with herbicides is unsustainable due to the rapid evolution of herbicide-resistant weeds. Precise knowledge of the ecology and biology of weeds is of utmost importance to determine the most appropriate nonchemical management techniques. Raphanus raphanistrum L. is an extremely invasive and noxious weed due to its prolific seed production, allelopathic potential, multiple herbicide resistance and biological potential. R. raphanistrum causes high crop yield losses and thus has become one of the most troublesome agricultural and environmental weeds. R. raphanistrum could exchange pollen with herbicide-tolerant canola and could become an environmental threat. This weed has evolved resistance to many herbicides, and relying exclusively on herbicide-based management could lead to severe crop loss and uneconomical cropping. Although reviews are available on the ecology and biology of R. raphanistrum, significant changes in tillage, weed management and agronomic practices have been occurring worldwide. Therefore, it is timely to review the status of noxious weeds in different agro-ecological zones and management scenarios. This review focuses on the response of R. raphanistrum to different cultural, mechanical, biological, chemical and integrated management strategies practiced in various agro-ecosystems, and its biological potential to thrive under different weed management tactics. In addition, this review facilitates a better understanding of R. raphanistrum and describes how weed management outcomes could be improved through exploiting the biology and ecology of the weed.


Assuntos
Herbicidas/farmacologia , Raphanus/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Ecossistema , Resistência a Herbicidas , Plantas Daninhas/efeitos dos fármacos , Controle de Plantas Daninhas
11.
PLoS One ; 15(2): e0228717, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027704

RESUMO

Conservation farming (CF), involving basin tillage, residue retention and crop rotation, combined with biochar may help to mitigate negative impacts of conventional agriculture. In this study, the effects of CF on the amount and quality of soil organic matter (SOM) and potential nitrogen (N) mineralization were investigated in a maize-soya-maize rotation in an Acrisol in Zambia. A large field was run under CF for 7 years and in the subsequent three growing seasons (2015-2018), four management practices were introduced to study effects on soil characteristics and crop yield. We tested i) a continuation of regular CF (CF-NORM) ii) CF without residue retention (CF-NO-RES); iii) Conventional (CONV), with full tillage and removal of residues; and iv) CF with 4 ton ha-1 pigeon pea biochar inside basins and residue retention (CF-BC). The experiment involved the addition of fertilizer only to maize, while soya received none. Soya yield was significantly higher in CF systems than in CONV. Maize yields were not affected by the different management practices probably due to the ample fertilizer addition. CF-NORM had a higher stock of soil organic carbon (SOC), higher N mineralization rates, more hot-water extractable carbon (HWEC; labile SOC) and particulate organic matter (POM) inside basins compared to the surrounding soil (outside basins). Our results suggest that the input of roots inside basins are more effective increasing SOM and N mineralization, than the crop residues that are placed outside basins. CONV reduced both quality and quantity of SOM and N mineralization as compared to CF inside basins. CF-BC increased the amount of SOC as compared with CF-NORM, whereas N mineralization rate and HWEC remained unaffected. The results suggest benefits on yield of CF and none of biochar; larger impact of root biomass on the build-up of SOM than crop residues; and high stability of biochar in soil.


Assuntos
Agricultura/métodos , Carbono/análise , Carvão Vegetal/farmacologia , Produtos Agrícolas/crescimento & desenvolvimento , Minerais/química , Nitrogênio/química , Solo/química , Biomassa , Conservação dos Recursos Naturais , Produtos Agrícolas/efeitos dos fármacos , Umidade
12.
Environ Pollut ; 256: 113466, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31679879

RESUMO

Since the Industrial Revolution, the global ambient O3 concentration has more than doubled. Negative impact of O3 on some common crops such as wheat and soybeans has been widely recognized, but there is relatively little information about maize, the typical C4 plant and third most important crop worldwide. To partly compensate this knowledge gap, the maize cultivar (Zhengdan 958, ZD958) with maximum planting area in China was exposed to a range of chronic ozone (O3) exposures in open top chambers (OTCs). The O3 effects on this highly important crop were estimated in relation to two O3 metrics, AOT40 (accumulated hourly O3 concentration over a threshold of 40 ppb during daylight hours) and POD6 (Phytotoxic O3 Dose above a threshold flux of 6 nmol O3 m-2 s-1 during a specified period). We found that (1) the reduced light-saturated net photosynthetic rate (Asat) mainly caused by non-stomatal limitations across heading and grain filling stages, but the stomatal limitations at the former stage were stronger than those at the latter stage; (2) impact of O3 on water use efficiency (WUE) of maize was significantly dependent on developmental stage; (3) yield loss induced by O3 was mainly due to a reduction in kernels weight rather than in the number of kernels; (4) the performance of AOT40 and POD6 was similar, according to their determination coefficients (R2); (5) the order of O3 sensitivity among different parameters was photosynthetic parameters > biomass parameters > yield-related parameters; (6) Responses of Asat to O3 between heading and gran filling stages were significantly different based on AOT40 metric, but not POD6. The proposed O3 metrics-response relationships will be valuable for O3 risk assessment in Asia and also for crop productivity models including the influence of O3.


Assuntos
Poluentes Atmosféricos/toxicidade , Ozônio/toxicidade , Fotossíntese/efeitos dos fármacos , Zea mays/fisiologia , Poluentes Atmosféricos/análise , Ásia , Biomassa , China , Produtos Agrícolas/efeitos dos fármacos , Ozônio/análise , Folhas de Planta/química , Soja/efeitos dos fármacos , Triticum/efeitos dos fármacos , Zea mays/efeitos dos fármacos
13.
Chemosphere ; 242: 125185, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31689637

RESUMO

Direct reuse of reclaimed wastewater (RWW) in agriculture has recently received increasing attention as a possible solution to water scarcity. The presence of contaminants of emerging concern (CECs) in RWW can be critical, as these chemicals can be uptaken in irrigated crops and eventually ingested during food consumption. In the present study, an integrated model was developed to predict the fate of CECs in water reuse systems where RWW is used for edible crops irrigation. The model was applied to a case study where RWW (originating from a municipal wastewater treatment plant) is discharged into a water channel, with subsequent irrigation of silage maize, rice, wheat and ryegrass. Environmental and human health risks were assessed for 13 CECs, selected based on their chemical and hazard characteristics. Predicted CEC concentrations in the channel showed good agreement with available measurements, indicating potential ecotoxicity of some CECs (estrogens and biocides) due to their limited attenuation. Plant uptake predictions were in good agreement with existing literature data, indicating higher uptake in leaves and roots than fruits. Notably, high uncertainties were shown for weakly acidic CECs, possibly due to degradation in soil and pH variations inside plants. The human health risk due to the ingestion of wheat and rice was assessed using the threshold of toxicological concern and the hazard quotient. Both approaches predicted negligible risk for most CECs, while sulfamethoxazole and 17α-ethinylestradiol exhibited the highest risk for consumers. Alternative scenarios were evaluated to identify possible risk minimization strategies (e.g., adoption of a more efficient irrigation system).


Assuntos
Irrigação Agrícola/métodos , Medição de Risco , Águas Residuárias/química , Irrigação Agrícola/normas , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/metabolismo , Humanos , Modelos Teóricos , Triticum/metabolismo , Águas Residuárias/toxicidade , Poluentes Químicos da Água/efeitos adversos , Poluentes Químicos da Água/análise , Zea mays/metabolismo
14.
Chemosphere ; 238: 124555, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31454746

RESUMO

Pesticide residues in bee products is still a major issue. However, the relations to botanical source and land use characteristics are not clear. The large variability of residues detected questions the suitability of bee-collected- and other hive materials as indicators for environmental contamination. The aim of our study was to clarify whether different beehive matrices contain similar pesticide residues, and how these are correlated with forage preferences and land use types in foraging areas. We tested bee-collected pollen, beebread, honey, nurse bees and honey bee larvae for the presence of concurrently used agricultural pesticides in Estonia. Samples were collected at the end of May and mid-July to include the main crop in northern region - winter and spring oilseed rape (Brassica napus). We saw that different beehive matrices contained various types of pesticide residues in different proportions: pollen and beebread tended to contain more insecticides and fungicides, whereas herbicides represented the primary contaminant in honey. The variations were related to collection year and time but were not related to crops as basic forage resource nor the land use type. We found few positive correlations between amount of pesticides and proportion of pollen from any particular plant family. None of these correlations were related to any land-use type. We conclude that pesticide residues in different honey bee colony components vary largely in amount and composition. The occurrence rate of pesticide residues was not linked to any particular crop.


Assuntos
Abelhas/efeitos dos fármacos , Brassica napus/crescimento & desenvolvimento , Produtos Agrícolas/crescimento & desenvolvimento , Mel/análise , Resíduos de Praguicidas/análise , Pólen/química , Animais , Brassica napus/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Estônia , Estações do Ano
15.
Ecotoxicol Environ Saf ; 187: 109841, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31677566

RESUMO

Drought stress is one of the extreme effects of climate change causing large losses in production of crop plants. The risk of recurrent droughts has increased in next decades hence, the development of shot-gun, inexpensive and effective approaches is essential to ensure high yield of crops in drought-prone areas of the world. Exogenous application of nutrients such as potassium (K) has been reported to increase abiotic resistance and improve yield in crops however, knowledge regarding interaction of K with osmoprotectants like chitosan (Ct) still remains elusive. Here, we report the effects of individual or combined K (using K2SO4 as a source) or Ct application on growth, physiological processes and antioxidative defense system of sunflower under drought stress. At first, various doses of K (0, 5, 10, 15, 20, 25 g/l) and Ct (0, 0.1, 0.2, 0.3, 0.4, 0.5 g/l) were foliar applied to evaluate their role in improving plant biomass, water status and total chlorophyll in drought-induced seedlings of sunflower. The optimized K (11.48 g/l) and Ct (0.28 g/l) doses were further tested in second experiment to understand the underlying mechanisms of drought tolerance. Foliar K + Ct spray markedly enhanced the leaf gas exchange characteristics, increased proline, soluble proteins, and free amino acids, upregulated antioxidant defense system and helped to maintain plant water status in sunflower exposed to drought stress. The impact of drought stress was more pronounced at vegetative than reproductive stage and positive effects of combined K and Ct application were related to improved physiological and metabolic processes to improve yield and quality of sunflower under drought stress.


Assuntos
Antioxidantes/metabolismo , Quitosana/farmacologia , Secas , Helianthus/efeitos dos fármacos , Potássio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Biomassa , Clorofila/metabolismo , Mudança Climática , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Helianthus/crescimento & desenvolvimento , Helianthus/metabolismo , Água/metabolismo
16.
Regul Toxicol Pharmacol ; 111: 104572, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31884154

RESUMO

Regulations governing the safety assessment of genetically engineered (GE) crops require studies that measure the expression levels of the transgene products (proteins and double-stranded RNA) in the GE crop; furthermore, the regulations also often mandate the inclusion of an entry of the GE crop that is sprayed with the herbicide to which tolerance was engineered and a non-sprayed entry of the GE crop in said studies. The hypothesized unique risk of altered transgene expression in response to application of herbicides related to herbicide-tolerant GE crops, compared with application of other herbicides, is not readily apparent. Field studies were conducted with GE maize, soybean, and cotton breeding stacks containing multiple herbicide tolerance traits; studies included plots that were sprayed with the trait-related herbicides and plots that were unsprayed. The GE herbicide-tolerance traits and complimentary herbicides investigated here comprise the majority of those that are currently in commercial use. Transgene product expression was characterized in crop tissues that were collected throughout the growing season. Results confirm the expectation, which is based on the fact that modes of action and regulatory elements in the genetic constructs of the herbicide-tolerance traits are well understood, that applying herbicides associated with GE herbicide-tolerance traits does not meaningfully affect transgene expression. These findings call into question the routine requirement for the inclusion of herbicide sprayed and non-sprayed entries in transgene-expression studies designed to support risk assessment.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Herbicidas/farmacologia , Plantas Geneticamente Modificadas/efeitos dos fármacos , Transgenes/efeitos dos fármacos , Zea mays/efeitos dos fármacos , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Engenharia Genética , Plantas Geneticamente Modificadas/genética , Transgenes/genética , Zea mays/genética , Zea mays/metabolismo
17.
Int J Mol Sci ; 21(1)2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31878296

RESUMO

Soil salinization is one of the major environmental stressors hampering the growth and yield of crops all over the world. A wide spectrum of physiological and biochemical alterations of plants are induced by salinity, which causes lowered water potential in the soil solution, ionic disequilibrium, specific ion effects, and a higher accumulation of reactive oxygen species (ROS). For many years, numerous investigations have been made into salinity stresses and attempts to minimize the losses of plant productivity, including the effects of phytohormones, osmoprotectants, antioxidants, polyamines, and trace elements. One of the protectants, selenium (Se), has been found to be effective in improving growth and inducing tolerance against excessive soil salinity. However, the in-depth mechanisms of Se-induced salinity tolerance are still unclear. This review refines the knowledge involved in Se-mediated improvements of plant growth when subjected to salinity and suggests future perspectives as well as several research limitations in this field.


Assuntos
Antioxidantes/metabolismo , Produtos Agrícolas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Selênio/metabolismo , Produtos Agrícolas/efeitos dos fármacos , Tolerância ao Sal , Cloreto de Sódio/farmacologia
18.
World J Microbiol Biotechnol ; 35(11): 177, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31696403

RESUMO

Plant biostimulants are defined as materials containing microorganisms or substances whose function when applied to plants or the rhizosphere is to stimulate natural mechanisms to enhance plant growth, nutrient use efficiency, tolerance to abiotic stressors and crop quality, independent of their nutrient content. In agriculture, seaweeds (Macroalgae) have been used in the production of plant biostimulants while microalgae still remain unexploited. Microalgae are single cell microscopic organisms (prokaryotic or eukaryotic) that grow in a range of aquatic habitats, including, wastewaters, pounds, lakes, rivers, oceans, and even humid soils. These photosynthetic microorganisms are widely described as renewable sources of biofuels, bioingredients and biologically active compounds, such as polyunsaturated fatty acids (PUFAs), carotenoids, phycobiliproteins, sterols, vitamins and polysaccharides, which attract considerable interest in both scientific and industrial communities. Microalgae polysaccharides have so far proved to have several important biological activities, making them biomaterials and bioactive products of increasing importance for a wide range of applications. The present review describes microalgae polysaccharides, their biological activities and their possible application in agriculture as a potential sustainable alternative for enhanced crop performance, nutrient uptake and resilience to environmental stress. This review does not only present a comprehensive and systematic study of Microalgae polysaccharides as plant biostimulants but considers the fundamental and innovative principles underlying this technology.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Microalgas/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Polissacarídeos/metabolismo , Produtos Biológicos/metabolismo , Biotecnologia/métodos , Produtos Agrícolas/metabolismo , Estresse Fisiológico/efeitos dos fármacos
19.
Appl Microbiol Biotechnol ; 103(23-24): 9287-9303, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31707442

RESUMO

Synthetic chemical pesticides have been used for many years to increase the yield of agricultural crops. However, in the future, this approach is likely to be limited due to negative impacts on human health and the environment. Therefore, studies of the secondary metabolites produced by agriculturally important microorganisms have an important role in improving the quality of the crops entering the human food chain. In this review, we have compiled information about the most important secondary metabolites of fungal species currently used in agriculture pest and disease management.


Assuntos
Anti-Infecciosos/metabolismo , Agentes de Controle Biológico/metabolismo , Produtos Agrícolas/microbiologia , Fungos/metabolismo , Metabolismo Secundário , Agricultura , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Agentes de Controle Biológico/química , Agentes de Controle Biológico/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Fungos/classificação , Controle Biológico de Vetores , Praguicidas/química , Praguicidas/metabolismo , Praguicidas/farmacologia
20.
Int J Mol Sci ; 20(21)2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31661847

RESUMO

Grain number per panicle is an important component of grain yield in sorghum (Sorghum bicolor (L.)) and other cereal crops. Previously, we reported that mutations in multi-seeded 1 (MSD1) and MSD2 genes result in a two-fold increase in grain number per panicle due to the restoration of the fertility of the pedicellate spikelets, which invariably abort in natural sorghum accessions. Here, we report the identification of another gene, MSD3, which is also involved in the regulation of grain numbers in sorghum. Four bulked F2 populations from crosses between BTx623 and each of the independent msd mutants p6, p14, p21, and p24 were sequenced to 20× coverage of the whole genome on a HiSeq 2000 system. Bioinformatic analyses of the sequence data showed that one gene, Sorbi_3001G407600, harbored homozygous mutations in all four populations. This gene encodes a plastidial ω-3 fatty acid desaturase that catalyzes the conversion of linoleic acid (18:2) to linolenic acid (18:3), a substrate for jasmonic acid (JA) biosynthesis. The msd3 mutants had reduced levels of linolenic acid in both leaves and developing panicles that in turn decreased the levels of JA. Furthermore, the msd3 panicle phenotype was reversed by treatment with methyl-JA (MeJA). Our characterization of MSD1, MSD2, and now MSD3 demonstrates that JA-regulated processes are critical to the msd phenotype. The identification of the MSD3 gene reveals a new target that could be manipulated to increase grain number per panicle in sorghum, and potentially other cereal crops, through the genomic editing of MSD3 functional orthologs.


Assuntos
Produtos Agrícolas/enzimologia , Ciclopentanos/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Oxilipinas/metabolismo , Sorghum/enzimologia , Alelos , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Ciclopentanos/farmacologia , Grão Comestível/efeitos dos fármacos , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Sequenciamento de Nucleotídeos em Larga Escala , Ácido Linoleico/química , Ácido Linoleico/metabolismo , Mutação , Oxilipinas/farmacologia , Fenótipo , Sementes/efeitos dos fármacos , Sementes/genética , Sementes/crescimento & desenvolvimento , Sorghum/genética , Sorghum/metabolismo , Ácido alfa-Linoleico/biossíntese , Ácido alfa-Linoleico/química
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