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181.
Elizabeth Selene Gmez‐Acata Isaias Valencia‐Becerril Cesar Valenzuela‐Encinas Alma Socorro Velsquez‐Rodríguez Yendi Ebenezer Navarro‐Noya Nina Montoya‐Ciriaco Mayra Cecilia Surez‐Arriaga Aketsally Rojas‐Valdez Basilio Gabriel Reyes‐Reyes Marco Luna‐Guido Luc Dendooven 《Land Degradation \u0026amp; Development》2016,27(4):1122-1130
In this study, the effect of deforestation and cultivation of maize (Zea mays L.) on the physicochemical characteristics and the bacterial community structure in soil were studied at the national park Área de Protección de Flora y Fauna Nevado de Toluca in Mexico. Soil was sampled from three forested areas in the national park, from three deforested areas grazed by animals and from three areas cultivated with maize. The soil was characterized chemically and biologically, whilst the bacterial community structure was investigated through 454 pyrosequencing of the 16S rRNA gene. The pH in the forest soil decreased from 6·1 to 5·3 in the maize‐cultivated soil, whilst the soil organic C content decreased 1·4 times in the arable soil compared with the forest soil. The microbial biomass C decreased 2·9 times in the arable soil compared with the forest soil, but the metabolic quotient qCO2 (ratio basal respiration to microbial biomass C) nearly doubled. Deforestation and maize cultivation reduced the abundance of Proteobacteria, Actinobacteria and Bacteroidetes, whereas Acidobacteria, Chloroflexi, Gemmatimonadetes and Firmicutes were resistant to these changes. It was found that soil characteristics were affected negatively by deforestation and nearly half of the organic matter was lost, and on these sloped fields, erosion will be high, further decreasing soil fertility. Although the relative abundance of a number of bacterial groups was reduced by deforestation, others were not affected by land‐use change. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
182.
Palacios SM Maggi ME Bazán CM Carpinella MC Turco M Muñoz A Alonso RA Nuñez C Cantero JJ Defago MT Ferrayoli CG Valladares GR 《Fitoterapia》2007,78(7-8):580-584
Aerial parts of 27 plant species native to Argentina were tested in anti-insect, germination inhibition and bactericide bio-assays. In antifeedant assays on Epilachna paenulata larvae, 11 species showed strong feeding deterrent effects (higher than 90% at 200 microg/cm(2)). Twelve plants strongly inhibited the germination of Avena sativa seeds, but only six inhibited Raphanus sativum germination at 10 mg/ml. Four plants showed complete growth inhibition of Escherichia coli at a concentration of 2 mg/ml. 相似文献
183.
Luis Trevio Cesar Lodeiros Jorge Vlez‐Falcones Cristina Chvez‐Alcivar Fernando Isea‐Len Alexandra E. Bermúdez‐Medranda Juan C. Vlez‐Chica Yanis Cruz‐Quintana Dayana Leal Ana María Santana‐Pieros Daniel Rodríguez‐Pesantes 《Aquaculture Research》2020,51(5):2052-2061
The growth and survival of Crassostrea gigas were evaluated in hanging culture in the Chone River estuary (Bahía de Caráquez), Manabí province, Ecuador. Oyster seeds (~10 mm) were confined in lantern nets at a density equal to the occupation of half the surface of the basket base, until reaching commercial size (80 mm). A sample for oyster biometric, parasitic and bacterial analysis was obtained monthly. Temperature, salinity, oxygen concentration, seston and phytoplankton biomass were determined. At the end of the study, the oysters were analysed for heavy metal concentration. The commercial oyster production was extrapolated to estimate the possible economic performance of a family production module (a 7 × 7 m bamboo raft). The results show a great biological feasibility of culture of C. gigas with harvests of commercial size oysters in only 5 months and acceptable survivals (accumulated >70%, after 3 weeks of crop seed selection). The heavy metal concentrations and the parasitological and bacteriological analyses did not indicate levels of contamination. The economic projections suggest that, even with a profitability of 57%, the initially invested capital could be recovered within the first harvest. 相似文献
184.
185.
da Silva Paulo Henrique Müller Junqueira Luis Renato de Araujo Marcio José Wilcken Carlos Frederico Moraes Mario Luiz Teixeira de Paula Rinaldo Cesar 《New Forests》2020,51(5):753-763
New Forests - Recently, pest occurrence in forest plantations has been increasing influenced by genotypes and environmental conditions such as climate change, thus impacting production negatively.... 相似文献
186.
Lucas de Castro Moreira da Silva Junior Cesar Avanzi Devison Souza Peixoto Marina Neves Merlo Emerson Borghi lvaro Vilela de Resende Salvador Francisco Acua-Guzman Bruno Montoani Silva 《国际水土保持研究(英文)》2021,9(4):591-604
Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage. Water deficit can be accentuated by soil physical degradation, which also triggers water losses through runoff and consequently soil erosion. Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years, information about soil erosion impacts and its mitigation are still not well understood; especially concerning the role of cropping system diversification and its effects on crop yield. Thus, the aim of this study was to assess whether ecological intensification of cropping systems –inclusion of a consorted perennial grass and crop rotation– could promote soil coverage and consequently decrease water erosion and soil, water, and nutrient losses. This work studied the effects of crop rotation and consorted Brachiaria, along with different levels of investment in fertilization on soil physical quality and on soil, water, and nutrient losses, and crop yields. Results proved that soybean monoculture (SS) is a system of low sustainability even under no-till in the Brazilian Cerrado conditions. It exhibited high susceptibility to soil, water, and nutrient losses, causing low crop yields. Our results showed that water losses in SS cropping system were approximately 10% of the total annual rainfall, and total K losses would require an additional 35% of K application. Conversely, ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions, increased grain yield, and promoted soil and water conservation: high soil cover rate, and low soil, water and nutrient losses. Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado. 相似文献
187.
Yih-Shen Hwang Mir S. Mulla Mary Mistrot Pope Cesar Rodriguez 《Pest management science》1982,13(5):517-522
N,N-Diethyl-, N,N-dipropyl-, N,N-di-isopropyl, and N,N-di-isobutylalkanamides in which the acyl moiety ranged from C8 to C21 were synthesised, and their larvicidal activity was determined against the first-instar larvae of the southern house mosquito Culex quinquefasciatus Say. The four homologous series of amides generally showed an increase in their larvicidal activity as the carbon number in the acyl moiety of the amides increased, until the activity reached a maximum. Subsequently, an increment of carbon number resulted in declining activity in the higher homologues, until the activity disappeared. N,N-Diethyltetradecanamide, N,N-dipropylundecanamide, N,N-di-isopropylundecanamide, and N,N-di-isobutlynonanamide or -dodecanamide were the most active compounds in their respective homologous series of amides; however, they were less active than their analogous N,N-dimethylalkanamides previously studied. 相似文献
188.
Growth Performance,Biochemical Responses,and Skeletal Muscle Development of Juvenile Nile Tilapia,Oreochromis niloticus,Fed with Increasing Levels of Arginine
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Dacley Neu Wilson Boscolo Micheli Zaminhan Fernanda Almeida Cesar Sary Wilson Furuya 《Journal of the World Aquaculture Society》2016,47(2):248-259
Tilapia, Oreochromis niloticus, is among the fish species with high potential for aquaculture in intensive farming, and Brazil is among the largest producers worldwide. Some of the amino acid requirements in practical diets for tilapia are still unknown. Thus, this study determined the dietary arginine requirements for Nile tilapia juveniles based on growth performance, hematological and biochemical responses, and muscle growth. Three hundred Nile tilapia juveniles (2.95 ± 0.79 g) were distributed into 20–500 L fiberglass aquaria and fed five extruded isoproteic (28% crude protein) and isoenergetic (3160 kcal/kg) diets formulated to contain 0.95, 1.10, 1.25, 1.40, and 1.55% arginine. Based on the quadratic regression analysis, the best results in weight gain, feed conversion, protein efficiency ratio, and protein retention were estimated in fish fed diets containing 1.36, 1.34, 1.36, and 1.37% arginine, respectively. The best amino acid body retention values were estimated in fish fed diets containing 1.31–1.37% arginine. Muscle growth occurred mainly by hyperplasia in fish fed 0.95% arginine, whereas reduction in the hyperplasia time and signs of hypertrophy occurred in fish fed 1.10–1.55% arginine diets. It was concluded that a diet with 1.36% of arginine (with 1.53% lysine in diet) meets the requirements of Nile tilapia juveniles. 相似文献
189.
Manuel Esteban Lucas-Borja Felipe Bastida Cesar Nicolás Jose Luis Moreno Antonio del Cerro Manuela Andrés 《European Journal of Soil Biology》2010,46(5):273-279
The effects of different Mediterranean vegetation cover on the biological and biochemical quality of soil is not well understood. The aim of this work is to evaluate the effects that different types of vegetation (forestry plots, mainly dominated by Spanish black pine (Pinus nigra Arn. ssp salzmannii) and herbaceous plots, where overstorey density is lower and natural herbaceous percentage is higher than in forestry plots) have in the biological properties of soil in Mediterranean humid climate. The impact of these plant communities on the biological soil quality was determined by several sensitive parameters related to the microbial activity of the soil such as soil respiration and some enzyme activities (urease, phosphatase and dehydrogenase). Development of vegetation (herbaceous and pines) was also determined and correlated with microbiological and biochemical indicators. Organic matter content in herbaceous sites was significantly higher than in forestry sites, ranging from 5.27 to 6.70 g 100 g?1 in herbaceous sites to 1.64–2.81 g 100 g?1 in forested areas. Herbaceous sites showed higher values of basal respiration and dehydrogenase activity than pine areas. However, the decrease of organic carbon content in pine areas led microbial activity enrichment per unit of carbon. These results conclude that vegetation cover significantly impacts soil microbial processes in Mediterranean humid climates, herbaceous vegetation having a more positive influence than forest vegetation on the biochemical and microbial activity of the soil, principally due to the higher accumulation of organic matter from plant remains. 相似文献
190.
Lucchetta L Manriquez D El-Sharkawy I Flores FB Sanchez-Bel P Zouine M Ginies C Bouzayen M Rombaldi C Pech JC Latché A 《Journal of agricultural and food chemistry》2007,55(13):5213-5220
Alcohol acyltransferases (AAT) play a key role in the biosynthesis of ester aroma volatiles in fruit. Three ripening-specific recombinant AATs of cantaloupe Charentais melon fruit (Cm-AAT1, Cm-AAT3, and Cm-AAT4) are capable of synthesizing thioether esters with Cm-AAT1 being by far the most active. All proteins, as well as AAT(s) extracted from melon fruit, are active as tetramers of around 200 kDa. Kinetic analysis demonstrated that CoA-SH, a product of the reaction, is an activator at low concentrations and an inhibitor at higher concentrations. This was confirmed by the addition of phosphotransacetylase at various concentrations, capable of modulating the level of CoA-SH in the reaction medium. Site-directed mutagenesis of some amino acids that were specific to the Cm-AAT sequences into amino acids that were consensus to other characterized AATs greatly affected the selectivity of the original protein and the number of esters produced. 相似文献