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1.
Plant Physiol Biochem ; 155: 42-58, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32738581

RESUMO

Abrupt drought-flood alternation is a frequent meteorological disaster during the summer in Southern China. The study of physiological and translation mechanisms of rice yield recovery after abrupt drought-flood alternation has great potential benefits in field production. Our results showed that yield recovery upon nitrogen (N) application after abrupt drought-flood alternation was due to the increase in effective panicle numbers per plant. The N application resulted in the regulation of physiological and biochemical as well as growth development processes, which led to a rapid growth recovery effect after abrupt drought-flood alternation stress in rice. Using ribosome profiling combined with RNA sequencing (RNA-seq) technology, the interactions between transcription and translation for N application after abrupt drought-flood alternation were analyzed. It was found that a small proportion of response genes were shared at the transcriptional and translational levels, that is, 14% of the expressed genes were upregulated and 6.6% downregulated. Further analysis revealed that the translation efficiency (TE) of the genes was influenced by their sequence characteristics, including their GC content, coding sequence length and normalized minimal free energy. Compared with the number of untranslated upstream open reading frames (uORFs), the increased number of translated uORFs promoted the improvement of TE. The TE of the uORFs for N application was lower than the control without N application after abrupt drought-flood alternation. This study characterizes the translational regulatory pattern in response to N application after abrupt drought-flood alternation stress.


Assuntos
Secas , Inundações , Nitrogênio/administração & dosagem , Oryza , Ribossomos/metabolismo , Nitrogênio/metabolismo , Fases de Leitura Aberta , Oryza/genética , Oryza/crescimento & desenvolvimento , Biossíntese de Proteínas
2.
Sci Rep ; 10(1): 11063, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32632136

RESUMO

Biochar-based controlled release nitrogen fertilizers (BCRNFs) have received increasing attention due to their ability to improve nitrogen-use efficiency (NUE) and increase crop yields. We previously developed a novel BCRNF, but its effects on soil microbes, NUE, and crop yields have not been reported. Therefore, we designed a pot experiment with five randomised treatments: CK (without urea and biochar), B (addition biochar without urea), B + U (biochar mixed urea), Urea (addition urea without biochar), and BCRNF (addition BCRNF), to investigate the effects of BCRNF on nitrifiers and denitrifiers, and how these impact nitrogen supply and NUE. Results of high-throughput sequencing revealed bacterial community groups with higher nutrient metabolic cycling ability under BCRNF treatment during harvest stage. Compared to Urea treatment, BCRNF treatment stimulated nitrification by increasing the copy number of the bacterial amoA gene and reducing nitrous oxide emission by limiting the abundance of nirS and nirK. Eventually, BCRNF successfully enhanced the yield (~ 16.6%) and NUE (~ 58.79%) of rape by slowly releasing N and modulating the abundance of functional microbes through increased soil nitrification and reduced denitrification, as compared with Urea treatment. BCRNF significantly improved soil NO3-, leading to an increase in N uptake by rape and NUE, thereby promoting rape growth and increasing grain yield.


Assuntos
Brassica napus/crescimento & desenvolvimento , Brassica napus/metabolismo , Fertilizantes , Nitrogênio/administração & dosagem , Nitrogênio/metabolismo , Disponibilidade Biológica , Biomassa , Carvão Vegetal/administração & dosagem , Carvão Vegetal/química , Preparações de Ação Retardada , Fertilizantes/análise , Fluoresceínas/metabolismo , Nitrificação , Solo/química , Microbiologia do Solo , Urease/metabolismo
3.
Appl Environ Microbiol ; 86(19)2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32709729

RESUMO

Learning more about the biodiversity and composition of arbuscular mycorrhizal fungi (AMF) under alternative agricultural management scenarios may be important to the sustainable intensification of switchgrass grown as a bioenergy crop. Using PacBio single-molecule sequencing and taxonomic resolution to the level of amplicon sequence variant (ASV), we assessed the effects of nitrogen amendment on AMF associating with switchgrass and explored relationships between AMF and switchgrass yield across three sites of various productivities in Wisconsin. Nitrogen amendment had little effect on AMF diversity metrics or community composition. While AMF ASV diversity was not correlated with switchgrass yield, AMF family richness and switchgrass yield had a strong, positive relationship at one of our three sites. Each of our sites was dominated by unique ASVs of the species Paraglomus brasilianum, indicating regional segregation of AMF at the intraspecific level. Our molecular biodiversity survey identified putative core members of the switchgrass microbiome, as well as novel clades of AMF, especially in the order Paraglomerales and the genus Nanoglomus Furthermore, our phylogenies unite the cosmopolitan, soil-inhabiting clade deemed GS24 with Pervetustaceae, an enigmatic family prevalent in stressful environments. Future studies should isolate and characterize the novel genetic diversity found in switchgrass agroecosystems and explore the potential yield benefits of AMF richness.IMPORTANCE We assessed the different species of beneficial fungi living in agricultural fields of switchgrass, a large grass grown for biofuels, using high-resolution DNA sequencing. Contrary to our expectations, the fungi were not greatly affected by fertilization. However, we found a positive relationship between plant productivity and the number of families of beneficial fungi at one site. Furthermore, we sequenced many species that could not be identified with existing reference databases. One group of fungi was highlighted in an earlier study for being widely distributed but of unknown taxonomy. We discovered that this group belonged to a family called Pervetustaceae, which may benefit switchgrass in stressful environments. To produce higher-yielding switchgrass in a more sustainable manner, it could help to study these undescribed fungi and the ways in which they may contribute to greater switchgrass yield in the absence of fertilization.


Assuntos
Fertilizantes/análise , Micobioma/fisiologia , Micorrizas/fisiologia , Panicum/microbiologia , Microbiologia do Solo , Agricultura , Biocombustíveis , Nitrogênio/administração & dosagem , Wisconsin
4.
PLoS One ; 15(6): e0233735, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497128

RESUMO

Many fertilization models have been created to scientifically determine the amount of fertilization. With the same purpose, we constructed a nitrogen (N) application model, the leaf value model, which can make N fertilizer decisions in a timely, fast and nondestructive manner during rice planting. However, only one area (A1, Jiuzhou Town, Xixiu District, Guizhou Province) and one cultivar (Qyou6) were involved in the construction of the leaf value model. Its stability and applicability could not be well evaluated. Thus, we chose another area (A2, Jiuzhou Town, Huangping County, Guizhou Province) in Guizhou Province and carried out the experiment by using four cultivars (Nie5you5399, Qyou6, Yixiangyou2115 and Zhongzheyou8) for the leaf value model construction. Compared with the average value of apparent total N uptake (Nz) obtained in 2 years in the A1 area, that in the Qyou6 leaf value model in the A2 area increased by 12%, reaching 635.72 kg ha-1, whereas the corresponding target yield changed slightly, reaching 10,999.90 kg ha-1. Simultaneously, the linear relationship between several good SPAD value-derived indexes (Ys) and apparent N supply of the field (Nx) was still significant or extremely significant in the Qyou6 leaf value model. Compared with the A1 area, it slightly differed, and the R2 of SPADL1 was higher than that of SPADL3×L4/mean. In the leaf value model of the other three cultivars, the relationship between yield and Nx and that between Ys and Nx were significant or extremely significant. The Nz of Yixiangyou2115 and Zhongzheyou8 (618.33 and 617.76 kg ha-1) were close to that of Qyou6 and the corresponding target yields were 10313.36 and 10301.99 kg ha-1, respectively. The Nz and target yield of Nie5you5399 were lowest at 546.63 and 10680.24 kg ha-1, respectively. In general, this study showed that relationships used in the construction of leaf value model had certain stability and applicability to difference areas and cultivars. The leaf value model can be considered in N fertilizer decision-making of rice planting management.


Assuntos
Fertilizantes , Modelos Biológicos , Nitrogênio/administração & dosagem , Oryza/fisiologia , Folhas de Planta/fisiologia , Clorofila/análise , Produção Agrícola/métodos , Oryza/anatomia & histologia , Oryza/química , Folhas de Planta/química , Solo/química
5.
PLoS One ; 15(4): e0227582, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32302306

RESUMO

Molecular hydrogen is thought to have an inhibitory effect on oxidative stress, thereby attenuating the onset and progression of various diseases including cardiovascular disease; however, few reports have assessed the preventive effect of constitutive inhalation of hydrogen gas on of vascular remodeling. Here, we investigated the effect of constitutive inhalation of hydrogen gas on vascular neointima formation using a cuff-induced vascular injury mouse model. After constitutive inhalation of compressed hydrogen gas (O2 21%, N2 77.7%, hydrogen 1.3%) or compressed air only (O2 21%, N2 79%) by C57BL/6 mice for 2 weeks from 8 weeks of age in a closed chamber, inflammatory cuff injury was induced by polyethylene cuff placement around the femoral artery under anesthesia, and hydrogen gas administration was continued until sampling of the femoral artery. Neointima formation, accompanied by an increase in cell proliferation, was significantly attenuated in the hydrogen group compared with the control group. NADPH oxidase NOX1 downregulation in response to cuff injury was shown in the hydrogen group, but the expression levels of NADPH oxidase subunits, p40phox and p47phox, did not differ significantly between the hydrogen and control groups. Although the increase in superoxide anion production did not significantly differ between the hydrogen and control groups, DNA damage was decreased as a result of reduction of reactive oxygen species such as hydroxyl radical (⋅OH) and peroxynitrite (ONOO-) in the hydrogen group. These results demonstrate that constitutive inhalation of hydrogen gas attenuates vascular remodeling partly via reduction of oxidative stress, suggesting that constitutive inhalation of hydrogen gas at a safe concentration in the living environment could be an effective strategy for prevention of vascular diseases such as atherosclerosis.


Assuntos
Hidrogênio/administração & dosagem , Isquemia Miocárdica/prevenção & controle , Neointima/prevenção & controle , Remodelação Vascular/efeitos dos fármacos , Lesões do Sistema Vascular/complicações , Administração por Inalação , Animais , Dano ao DNA/efeitos dos fármacos , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Gases/administração & dosagem , Gases/química , Humanos , Radical Hidroxila/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Isquemia Miocárdica/patologia , NADPH Oxidase 1/metabolismo , Neointima/etiologia , Neointima/patologia , Nitrogênio/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Oxigênio/administração & dosagem , Ácido Peroxinitroso/metabolismo
6.
BMC Plant Biol ; 20(1): 106, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143578

RESUMO

BACKGROUND: The Eurasian steppe is an important vegetation type characterized by cold, arid and nitrogen poor conditions. At the Eastern edge, including in the Songnen grassland, the vegetation is dominated by Leymus chinensis (henceforth L. chinensis) and is increasing threatened by elevated anthropogenic nitrogen deposition. L. chinensis is a perennial grass that mainly reproduces vegetatively and its sexual reproduction is limited. However, sexual reproduction plays an important role influencing colonization after large disturbances. To develop an understanding of how elevated nitrogen deposition changes the plant community structure and functioning we need a better understanding how sexual reproduction of L. chinensis changes with nitrogen enrichment. Here we report on a field experiment where we added 10 g N m- 2 yr- 1 and examined changes in seed traits, seed germination and early seedling growth. RESULTS: Nitrogen addition increased seed production by 79%, contributing to this seed increases were a 28% increase in flowering plant density, a 40% increase in seed number per plant and a 11% increase in seed weight. Seed size increased with a 42% increase in large seeds and a 49% decrease in the smallest seed size category. Seed germination success improved by 10% for small seeds and 18% for large seeds. Combined, the increased in seed production and improved seed quality doubled the potential seed germination. Subsequent seedling above and below-ground biomass also significantly increased. CONCLUSIONS: All aspects of L. chinensis sexual reproduction increased with nitrogen addition. Thus, L. chinensis competitive ability may increase when atmospheric nitrogen deposition increases, which may further reduce overall plant diversity in the low diversity Songnen grasslands.


Assuntos
Germinação/efeitos dos fármacos , Nitrogênio/metabolismo , Poaceae/fisiologia , Plântula/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Atmosfera , Nitrogênio/administração & dosagem , Poaceae/efeitos dos fármacos , Poaceae/crescimento & desenvolvimento , Reprodução/efeitos dos fármacos , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos
7.
Physiol Rep ; 8(3): e14365, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32026576

RESUMO

Preclinical imaging studies of fetal hemodynamics require anesthesia to immobilize the animal. This may induce cardiovascular depression and confound measures under investigation. We compared the impact of four anesthetic regimes upon maternal and fetal blood gas and hemodynamics during baseline periods of normoxia, and in response to an acute hypoxic challenge in pregnant sheep. Merino ewes were surgically prepared with maternal and fetal vascular catheters and a fetal femoral artery flow probe at 105-109 days gestation. At 110-120 days gestation, ewes were anesthetized with either isoflurane (1.6%), isoflurane (0.8%) plus ketamine (3.6 mg·kg-1 ·h-1 ), ketamine (12.6 mg·kg-1 ·h-1 ) plus midazolam (0.78 mg·kg-1 ·h-1 ), propofol (30 mg·kg-1 ·h-1 ), or remained conscious. Following 60 min of baseline recording, nitrogen was administered directly into the maternal trachea to displace oxygen and induce maternal and thus fetal hypoxemia. During normoxia, maternal PaO2 was ~30 mmHg lower in anesthetized ewes compared to conscious controls, regardless of the type of anesthesia (p < .001). There was no effect of anesthesia on fetal mean arterial blood pressure (MAP; p > .05), but heart rate was 32 ± 8 bpm lower in fetuses from ewes administered isoflurane (p = .044). During maternal hypoxia, fetal MAP increased, and peripheral blood flow decreased in all fetuses except those administered propofol (p < .05). Unexpectedly, hypoxemia also induced fetal tachycardia regardless of the anesthetic regime (p < .05). These results indicate that despite maternal anesthesia, the fetus can mount a cardiovascular response to acute hypoxia by increasing blood pressure and reducing peripheral blood flow, although the heart rate response may differ from when no anesthesia is present.


Assuntos
Anestesia/efeitos adversos , Hipóxia Fetal/fisiopatologia , Anestesia/métodos , Animais , Pressão Sanguínea , Feminino , Hipóxia Fetal/etiologia , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/efeitos adversos , Isoflurano/administração & dosagem , Isoflurano/efeitos adversos , Ketamina/administração & dosagem , Ketamina/efeitos adversos , Midazolam/administração & dosagem , Midazolam/efeitos adversos , Nitrogênio/administração & dosagem , Nitrogênio/efeitos adversos , Oxigênio/metabolismo , Propofol/administração & dosagem , Propofol/efeitos adversos , Fluxo Sanguíneo Regional , Ovinos
9.
Arq. bras. med. vet. zootec. (Online) ; 72(1): 136-144, Jan.-Feb. 2020. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1088918

RESUMO

This study evaluated the effect of detoxified castor meal on the reproductive performance, metabolic stress, milk production, and kid development in peripartum goats. The diet of the animals were with (DCM, n= 20) or without (WDCM, n= 21) detoxified castor meal during the entire gestation and until weaning, 60 days post-birth. No differences were observed in the gestation period, litter size, rate of multiple births, and mortality between the two groups. The postpartum plasma concentrations of progesterone remained below 1ng/mL in all animals, thus, confirming the absence of active corpora lutea. The thickness of sternum adipose tissue and loin area, levels of urea and cholesterol, milk production, and daily weight gain in the kids were low in the DCM group when compared to those in the WDCM group (P< 0.05). To conclude, the use of detoxified castor meal in peripartum goats resulted in lower level of performance in the kids because of reductions in the amount of milk received from their mothers during lactation. In addition, the diet containing detoxified castor meals was not efficient in recovering from the loss of stored body reserves able to initiate the recovery of the cyclic activity of the goats.(AU)


Este estudo avaliou o efeito da torta de mamona desintoxicada na reprodução, no estresse metabólico, na produção de leite e no desenvolvimento de cabritos no periparto de cabras. Um grupo foi alimentado com torta de mamona (DCM, n=20), e o outro (WDCM, n=21) não recebeu tal suplemento , durante a gestação até o desmame, 60 dias pós-parto. Não foram observadas diferenças significativas no período de gestação, no número de cabritos, na taxa de partos múltiplos e na mortalidade entre os dois grupos. Em todos os animais, a concentração plasmática de progesterona ficou abaixo de 1ng/mL, confirmando a ausência de atividade lútea. A espessura da gordura subcutânea do esterno e da área de olho-de-lombo, a concentração de ureia e colesterol, a produção de leite e o ganho de peso dos cabritos foram menores no grupo DCM (P<0,05). Conclui-se que o uso de torta de mamona desintoxicada no periparto de cabra resultou em cabritos mais leves devido à redução na produção de leite das matrizes e as cabras não retornaram ao cio, pois não recuperaram a massa corporal.(AU)


Assuntos
Animais , Feminino , Ricinus , Estresse Fisiológico , Lactação , Cabras/fisiologia , Animais Recém-Nascidos/crescimento & desenvolvimento , Nitrogênio/administração & dosagem , Progesterona , Suplementos Nutricionais
10.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 57(3): e168157, 2020. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1122182

RESUMO

Two experiments were conducted to evaluate the effect of the level and degradability of crude protein (CP) on the digestive metabolism and productive performance of dairy cows. In both experiments, 15 Holstein cows with 585 ± 40 kg of body weight were distributed in a Latin square design with five contemporary squares, three periods of 21 days and three treatments. In experiment 1, treatments consisted of three CP levels (130, 160 or 180 g CP/kg DM), while in experiment 2, the treatments consisted of three levels of rumen degradable protein (RDP; 80, 100 or 120 g RDP/kg DM) in diets with average of 163 g CP/kg DM. Variables evaluated in both experiments were dry matter intake (DMI), total apparent digestibility, milk yield (MY) and composition, ruminal fermentation and N balance. In experiment 1, the increase of CP from 130 to 180 linearly increased the organic matter, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake (kg) and the apparent total digestibility coefficient of DM and CP. In addition, a linear increase of MY, fat corrected milk (FCM) and daily production of fat, protein, lactose, casein and total solids was observed. A linear increase in ruminal ammoniacal nitrogen (NH3-N) concentration and nitrogen excretion in milk, feces and urine was also observed. However, there was no observed effect on SCFA concentration. In experiment 2, the increase of the RDP from 80 to 120 increased the DMI, MY, FCM, milk protein content and digestibility coefficient of the NDF, ADF and ethereal extract. Additionally, there was an increase in NH3-N concentration and milk nitrogen excretion. The studies indicated that the increase of CP content up to 100 g RDP/kg DM increased the DMI and the productive performance of the cows, but also increased urine N. Thus, it is desirable that the increase of the CP through the increase of the RDP is carried out up to 100 g of RDP/kg DM, since there is elimination of nitrogen, decrease of milk yield and decrease of propionic acid in values above that level.(AU)


Dois experimentos foram realizados com o objetivo de avaliar o efeito do nível e da degradabilidade da proteína bruta (PB) no metabolismo digestivo e no desempenho produtivo de vacas leiteiras. Nos dois experimentos, 15 vacas da raça Holandesa com 585 ± 40 kg de peso corporal foram distribuídas em delineamento do tipo quadrado latino com cinco quadrados contemporâneos, sendo três períodos de 21 dias e três tratamentos. No experimento 1, os tratamentos consistiram de três níveis de PB (130, 160 ou 180 g CP/kg de MS), enquanto que no experimento 2, os tratamentos consistiram de três níveis de proteína degradável no rúmen (PDR; 80, 100 ou 120 g de PDR/kg MS) em dietas com média de 163 g CP/kg MS. As variáveis avaliadas nos dois experimentos foram: consumo de matéria seca (CMS), digestibilidade aparente total, produção e composição do leite (PL), fermentação ruminal e balanço de N. No experimento 1, o aumento da PB de 130 para 180 aumentou linearmente o consumo de matéria orgânica, PB, fibra detergente neutro (FDN), fibra em detergente ácido (ADF) (kg) e o aparente coeficiente de digestibilidade total de MS e PB. Além disso, foi observado um aumento linear da PL, leite corrigido para gordura (LCG) e produção diária de gordura, proteína, lactose, caseína e sólidos totais. Também foi observado aumento linear na concentração de nitrogênio amoniacal ruminal (N-NH3) e excreção de nitrogênio no leite, fezes e urina. No entanto, não foi observado efeito na concentração de ácidos graxos de cadeia curta. No experimento 2, o aumento do PDR de 80 para 120 aumentou o CMS, PL, LCG, teor de proteína do leite e o coeficiente de digestibilidade do FDN, FDA e extrato etéreo. Além disso, houve aumento na concentração de N-NH3 e excreção de nitrogênio no leite. Os estudos indicaram que o aumento do teor de PB em até 100 g RDP/kg de MS aumentou o CMS e o desempenho produtivo das vacas, mas também aumentou o N urinário. Assim, é desejável que o aumento da PB através do aumento da PDR seja realizado até 100 g de PDR/kg de MS, uma vez que há eliminação de nitrogênio, diminuição da produção de leite e diminuição do ácido propiônico em valores acima desse nível.(AU)


Assuntos
Animais , Feminino , Bovinos , Rúmen , Fibras na Dieta/metabolismo , Proteínas na Dieta/metabolismo , Fermentação , Nitrogênio/administração & dosagem
11.
PLoS One ; 14(12): e0225708, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31815964

RESUMO

Culturing slowly growing tree seedlings is a potential approach for managing the conflict between the increasing demand for ornamental stock and the decreasing area of farmlands due to urbanization. In this study, Buddhist pine (Podocarpus macrophyllus [Thunb.] D. Don) seedlings were raised in multishelves with light-emitting diode lighting in the spectrum of 17:75:8 (red:green:blue) at 190-320 µmol m-2 s-1 with controlled temperature and relative humidity at 19.5°C and 60%, respectively. Seedlings were fed by exponential fertilization (EF) (nitrogen [N]-phosphorus [P]2O5-K2O, 10-7-9) at eight rates of 0 (control), 20 (E20), 40 (E40), 60 (E60), 80 (E80), 100 (E100), 120 (E120), and 140 (E140) mg N seedling-1 for four months through 16 fertilizer applications. The nutritional responses of Buddhist pine seedlings can be identified and classified into various stages in response to increasing doses, up to and over 120 N seedling-1. Morphological traits, i.e., the green color index and leaf area (LA) obtained by digital analysis and the fine root growth, all remained constant in response to doses that induced steady nutrient loading. LA had a positive relationship with most of the nutritional parameters. A dose range between 60 and 120 mg N seedling-1 was recommended for the culture of Buddhist pine seedlings. At this range of fertilizer doses, measuring the leaf area through digital scanning can easily and rapidly indicate the inherent nutrient status of the seedlings.


Assuntos
Fertilizantes , Pinus/crescimento & desenvolvimento , Reforma Urbana/métodos , Urbanização , Cor , Nitrogênio/administração & dosagem , Parques Recreativos , Fósforo/administração & dosagem , Pinus/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/fisiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento
12.
Arq. bras. med. vet. zootec. (Online) ; 71(6): 2049-2056, Nov.-Dec. 2019. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1055135

RESUMO

This study was carried out to evaluate the effect of nitrogen fertilization on tillering dynamics of Alexandergrass (Urochloa plantaginea (Link) Hitch) grazed by beef heifers in a rotational stocking grazing method. The experiment was conducted in a completely randomized design following a repeated measure arrangement, three levels of nitrogen (Zero, 150 and 300kg ha-1) and two area repetition. The classification of tillers into categories (basal and axillary) showed a greater number of basal tillers, due to their higher appearance rate, in the absence of nitrogen fertilization. Nitrogen fertilization promoted higher axillary tiller density. The use of nitrogen promotes the renewal of axillary tillers of Alexandergrass, without compromising the stability of the tiller population.(AU)


Esse estudo foi conduzido para avaliar o efeito da fertilização nitrogenada no perfilhamento do Papuã (Urochloa plantaginea (Link) Hitch) pastejado por novilhas de corte em um método de lotação rotacionada. O delineamento foi inteiramente casualizado com arranjo de medidas repetidas, três níveis de nitrogênio (Zero, 150 e 300kg ha -1 ) e duas repetições de área. A classificação dos perfilhos em categorias (basais e axilares) mostrou um maior número de perfilhos basais, devido à sua maior taxa de aparecimento, na ausência de adubação nitrogenada. A fertilização nitrogenada promoveu maior densidade de perfilhos axilares. O uso de nitrogênio promove renovação dos perfilhos axilares no Papuã, sem comprometer a estabilidade da população de plantas.(AU)


Assuntos
Animais , Feminino , Bovinos , Pastagens/métodos , Fertilizantes/análise , Poaceae/química , Nitrogênio/administração & dosagem
13.
Undersea Hyperb Med ; 46(4): 503-507, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31509906

RESUMO

We hypothesized that heart rate variability (HRV) can be used as a physiological monitor of exposures to hypercapnia. HRV was analyzed in 15 male subjects breathing air and then air plus 4%, 5% or 6% carbon dioxide (CO2). A progressive elevation in randomness of HRV best depicted as a divergence of data on Poincar é plots of self-similarity occurred as CO2 increased, and resolved when returning sd to ambient conditions. Results indicate that HRV may be useful as a prompt (⟨ 2 minute) early warning of hypercapnia that occurs prior to overt symptomatology.


Assuntos
Frequência Cardíaca , Hipercapnia/diagnóstico , Administração por Inalação , Adulto , Ar , Dióxido de Carbono/administração & dosagem , Estudos Cross-Over , Eletrocardiografia , Humanos , Hipercapnia/fisiopatologia , Masculino , Pessoa de Meia-Idade , Nitrogênio/administração & dosagem , Oxigênio/administração & dosagem , Sintomas Prodrômicos , Adulto Jovem
14.
Sci Total Environ ; 686: 1129-1139, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412509

RESUMO

Global change apart from ecosystem processes also influences the community structure of key organisms, such as arbuscular mycorrhizal fungi (AMF). We conducted a 3-year experiment where we suppressed with benomyl mycorrhiza to understand how AMF alter the plant community structure under warming and nitrogen (N) addition. The elemental content and foliar tissue stoichiometry of the dominant species Leymus chinensis and the subordinate species Puccinellia tenuiflora were studied along with soil nutrient stoichiometries. Overall, N addition enhanced plant N: phosphorus (P) ratios at a greater level than experimental warming did. Under global change conditions, AMF symbionts significantly increased soil available P concentrations, promoted plant P absorption and decreased the plant N:P ratios. AMF alleviate P limitation by reducing plant N:P ratios. Our results highlight that the negative influence of global change on plant productivity might cancel each other out through the additive effects of AMF and that global change will increase the dependency of plants on their mycorrhizal symbionts.


Assuntos
Aquecimento Global , Micorrizas/fisiologia , Nitrogênio/fisiologia , Fósforo/fisiologia , Poaceae/microbiologia , China , Fertilizantes/análise , Temperatura Alta , Nitrogênio/administração & dosagem
15.
Arq. bras. med. vet. zootec. (Online) ; 71(4): 1395-1402, jul.-ago. 2019. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1038629

RESUMO

The effect of four nitrogen levels (0, 40, 80 and 120kg N ha-1), applied before deferment on the beef cattle production and structural variables on Urochloa decumbens (signal grass) were assessed from January to October 2012 and from January to September 2013. A randomized block design with three replicates was adopted, in an arrangement of repeated measures in time (grazing period). An interaction effect between nitrogen level and grazing period was observed on extended-plant height and herbage mass. As the nitrogen levels were increased, extended-plant height, herbage mass, total herbage allowance, and efficiency of conversion of fertilizer into herbage were increased. Throughout the grazing period, pasture height, extended-plant height, percentage of leaves, herbage and morphological components allowance, and percentages of leaves and stems in the herbage apparently selected by the animal decreased. Nitrogen levels had no effect on average daily gain or gain per area in the first year. A fixed deferment period with increasing levels of nitrogen fertilization on signal grass pastures does not influence the average daily gain per animal, reduces the efficiency of the nitrogen fertilizer and negatively changes the structural characteristics of the pasture.(AU)


Foi avaliado o efeito de quatro doses de nitrogênio (0, 40, 80 e 120kg N ha -1 ), aplicadas antes do diferimento, sobre o desempenho de bovinos e as características estruturais de Urochloa decumbens (capim-braquiária), de janeiro a outubro de 2012 e de janeiro a setembro de 2013. Um delineamento de blocos ao acaso foi utilizado em arranjo de medidas repetidas no tempo (período de pastejo). Foi observada interação entre doses de nitrogênio e período de pastejo na altura da planta estendida e na massa de forragem. As doses de nitrogênio incrementaram a altura da planta estendida, a massa de forragem, a oferta de forragem e a eficiência de conversão do nitrogênio em forragem. No decorrer do período de pastejo, a altura do pasto, a altura da planta estendida, a porcentagem de lâminas foliares, a oferta de forragem e dos seus componentes morfológicos e a porcentagem de lâminas e colmos da forragem aparentemente selecionada pelos animais diminuíram. As doses de nitrogênio não exerceram efeito sobre o ganho diário e o ganho diário por área no primeiro ano. O período de diferimento fixo com aumento das doses de nitrogênio em pastos de capim-braquiária não influencia o ganho diário por animal, reduz a eficiência da adubação nitrogenada e afeta negativamente a estrutura do pasto.(AU)


Assuntos
Animais , Bovinos , Brachiaria/crescimento & desenvolvimento , Fenômenos Fisiológicos da Nutrição Animal , Nitrogênio/administração & dosagem , Pastagens/métodos , Fertilizantes
16.
PLoS One ; 14(7): e0219161, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31339879

RESUMO

Ammonium pulse attributed to runoff of urban surface and agriculture following heavy rain is common in inland aquatic systems and can cause profoundly effects on the growth of macrophytes, especially when combined with low light. In this study, three patterns of NH4-N pulse (differing in magnitude and frequency) were applied to examine their effects on the growth of three submersed macrophytes, namely, Myriophyllum spicatum, Potamogeton maackianus, and Vallisneria natans, in terms of biomass, height, branch/ramet number, root length, leaf number, and total branch length under high and low light. Results showed that NH4-N pulse caused negative effects on the biomass of the submerged macrphytes even on the 13th day after releasing NH4-N pulse. The negative effects on M. spicatum were significantly greater than that on V. natans and P. maackianus. The effects of NH4-N pulse on specific species depended on the ammonium loading patterns. The negative effects of NH4-N pulse on P. maackianus were the strongest at high loading with low frequency, and on V. natans at moderate loading with moderate frequency. For M. spicatum, no significant differences were found among the three NH4-N pulse patterns. Low light availability did not significantly aggregate the negative effects of NH4-N pulse on the growth of the submersed macrophytes. Our study contributes to revealing the roles of NH4-N pulse on the growth of aquatic plants and its species specific effects on the dynamics of submerged macrophytes in lakes.


Assuntos
Compostos de Amônio/administração & dosagem , Hydrocharitaceae/efeitos dos fármacos , Hydrocharitaceae/crescimento & desenvolvimento , Lagos/análise , Potamogetonaceae/efeitos dos fármacos , Potamogetonaceae/crescimento & desenvolvimento , Saxifragales/efeitos dos fármacos , Saxifragales/crescimento & desenvolvimento , Compostos de Amônio/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Biomassa , China , Ecossistema , Eutrofização/efeitos dos fármacos , Nitrogênio/administração & dosagem , Nitrogênio/toxicidade , Chuva/química , Água/análise , Poluentes Químicos da Água/administração & dosagem , Poluentes Químicos da Água/toxicidade
17.
Biosci Biotechnol Biochem ; 83(10): 1924-1936, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31244380

RESUMO

This study examined the physiological effects of different amounts of nitrogen (N) supplementation (0 to 2.72 kg/year) on the citrus cultivar Huangguogan (Citrus reticulata × Citrus sinensis). Root activity, chlorophyll content, and fruit quality were measured, and the activities of the antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (POD), and catalase (CAT), and the contents of malondialdehyde (MDA) and soluble protein in root, leaf, and fruit tissues were examined at different developmental stages. Root activity, chlorophyll content, fruit quality, antioxidant enzyme activity, MDA content, and soluble protein content increased in plants treated with an appropriate amount of N. Both excessive N and N deficiency decreased the content of MDA and the activities of antioxidant enzymes. Application of 1.36-1.81 kg N/year is suggested for citrus fertilization and the lower end of this range is recommended for minimizing environmental impact and production cost.


Assuntos
Antioxidantes/metabolismo , Catalase/metabolismo , Citrus/enzimologia , Citrus/crescimento & desenvolvimento , Nitrogênio/administração & dosagem , Peroxidase/metabolismo , Superóxido Dismutase/metabolismo , Clorofila/metabolismo , Citrus/metabolismo , Malondialdeído/metabolismo , Proteínas de Plantas/metabolismo , Estruturas Vegetais/enzimologia , Estruturas Vegetais/metabolismo
18.
Am J Vet Res ; 80(7): 631-636, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31246120

RESUMO

OBJECTIVE: To assess effects of nitrogen and helium on efficacy of an alveolar recruitment maneuver (ARM) for improving pulmonary mechanics and oxygen exchange in anesthetized horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were anesthetized twice in a randomized crossover study. Isoflurane-anesthetized horses in dorsal recumbency were ventilated with 30% oxygen and 70% nitrogen (treatment N) or heliox (30% oxygen and 70% helium; treatment H) as carrier gas. After 60 minutes, an ARM was performed. Optimal positive end-expiratory pressure was identified and maintained for 120 minutes. Throughout the experiment, arterial blood pressures, heart rate, peak inspiratory pressure, dynamic compliance (Cdyn), and Pao2 were measured. Variables were compared with baseline values and between treatments by use of an ANOVA. RESULTS: The ARM resulted in significant increases in Pao2 and Cdyn and decreases in the alveolar-arterial gradient in the partial pressure of oxygen in all horses. After the ARM and during the subsequent 120-minute phase, mean values were significantly lower for treatment N than treatment H for Pao2 and Cdyn. Optimal positive end-expiratory pressure was consistently 15 cm H2O for treatment N, but it was 10 cm H2O (4 horses) and 15 cm H2O (2 horses) for treatment H. CONCLUSIONS AND CLINICAL RELEVANCE: An ARM in anesthetized horses might be more efficacious in improving Pao2 and Cdyn when animals breathe helium instead of nitrogen as the inert gas.


Assuntos
Anestesia Geral/veterinária , Hélio/administração & dosagem , Cavalos/fisiologia , Nitrogênio/administração & dosagem , Oxigênio/administração & dosagem , Alvéolos Pulmonares/fisiologia , Anestesia Geral/métodos , Animais , Estudos Cross-Over , Feminino , Isoflurano/administração & dosagem , Masculino , Posicionamento do Paciente/métodos , Posicionamento do Paciente/veterinária , Distribuição Aleatória
19.
J Agric Food Chem ; 67(27): 7616-7625, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31251044

RESUMO

Rapid hydrolysis of urea results in further fertilization frequency and excessive nitrogen (N) input. A modified urea, dimethylolurea (DMU), was synthesized in this study. The structure of the sample was characterized by Fourier transform infrared and nuclear magnetic resonance analysis, manifesting the formation of DMU. N release investigation confirmed that DMU enabling provided a gradual N supply. The N leaching experiment indicated that increasing the applied DMU significantly reduced the NH4+-N, NO3--N, and total N leaching, compared with urea application alone. The application effect on maize and wheat was evaluated. The results revealed that singly applied DMU with 100% or 80% N input, irrespective of the amount, promoted crop yield and agronomic characteristic and N use efficiency (NUE) of maize and wheat, beyond urea with two split applications at the recommended rate. Thus, the potential availability of DMU was proven; this could be widely used in agricultural fields as a slow-release fertilizer.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Fertilizantes , Compostos de Metilureia/administração & dosagem , Nitrogênio/administração & dosagem , Agricultura/métodos , Preparações de Ação Retardada , Fertilizantes/análise , Compostos de Metilureia/síntese química , Compostos de Metilureia/química , Espectroscopia de Infravermelho com Transformada de Fourier , Triticum/crescimento & desenvolvimento , Zea mays/crescimento & desenvolvimento
20.
Diving Hyperb Med ; 49(2): 119-126, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31177518

RESUMO

INTRODUCTION: Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen (O2) fractions was investigated. METHODS: Eight male volunteers performed, in random order, two dry chamber dives breathing either air or EANx40 (40% O2-60% nitrogen) for 20 minutes (min) at 0.4 MPa. Cognition and arousal were assessed before the dive; upon arrival at 0.4 MPa; after 15 min exposure at 0.4 MPa; on surfacing and 30 min post-dive using behavioural computer-based testing psychology experiment building language (PEBL) and by CFFF while continuously recording brain oxygenation with near-infrared spectroscopy. RESULTS: In both breathing conditions, CFFF and PEBL demonstrated a significant inverse correlation (Pearson r of -0.90, P < 0.0001), improved cognitive abilities/cerebral arousal occurred upon arrival at 0.4 MPa followed by a progressive deterioration. Initial brain activation was associated with a significant increase in oxyhaemoglobin (HbO2) and a simultaneous decrease of deoxyhaemoglobin (HHb). The magnitude of the changes was significantly greater under EANx (P = 0.038). CONCLUSIONS: Since changes were not related to haemodynamic variables, HbO2 and HHb values indicate a significant, O2-dependent activation in the prefrontal cortex. Owing to the correlation with some tests from the PEBL, CFFF could be a convenient measure of cognitive performance/ability in extreme environments, likely under the direct influence of oxygen partial pressure, a potent modulator of IGN symptoms.


Assuntos
Disfunção Cognitiva , Mergulho , Nitrogênio/efeitos adversos , Oxigênio/efeitos adversos , Disfunção Cognitiva/induzido quimicamente , Mergulho/efeitos adversos , Fusão Flicker , Humanos , Nitrogênio/administração & dosagem , Oxigênio/administração & dosagem
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