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931.
Joséli Schwambach Carolina Michels Ruedell Márcia Rodrigues de Almeida Ricardo Miguel Penchel Elias Frank de Araújo Arthur G. Fett-Neto 《New Forests》2008,36(3):261-271
Eucalyptus globulus Labill and hybrids thereof have low lignin content, favoring cellulose extraction, but are often recalcitrant to clonal propagation.
This work analyzed biochemical and morphological changes during adventitious rooting of mini-cuttings of E. globulus × maidenni obtained from mini-stumps cultured in drip fertigated sand bed or intermittent flooding tray commercial propagation systems.
Morphological (% rooting, root number and length, mean rooting time) and biochemical parameters (peroxidase activity, total
phenolic content and flavonoid content) were monitored to characterize the rooting phases. All of the rooting parameters were
equivalent in both systems, indicating comparable efficiency of both methods in clonal propagation. Kinetic profiles of biochemical
parameters were also similar, although the activity of peroxidases was an order of magnitude higher and the phenolic content
about three times lower in cuttings derived from intermittent flooding-grown mini-stumps than in those derived from sand bed-grown
mini-stumps. Taken together, results suggest that rooting phases were similar in both systems: induction before day 5, formation
from day 5 to 15, and elongation from day 15 to 45. These data may contribute to the development of rooting phase-specific
mineral nutrient solutions to maximize clonal propagation and plant survival. 相似文献
932.
A. A. Linhares Luiz Fernando Linhares Rosalie R. R. Coelho 《Biology and Fertility of Soils》1998,27(2):162-167
Nine actinomycete melanins synthesized under various culture conditions, eight of them by actinomycete samples isolated from
Brazilian topsoils under savanna (cerrado) vegetation and one from an ATCC sample, were subjected to a two-step hydrolysis
procedure and the sugars released qualitatively and quantitatively determined by capillary gas-liquid chromatography (GLC).
Humic acids (HAs) extracted from these soils, analysed previously, were used for comparison. The neutral sugars glucose, galactose,
mannose, xylose, arabinose, ribose, rhamnose and fucose and the alcohol sugar inositol were present in varying amounts in
most of the melanins analysed. The same sugars were present in the HAs used for comparison, except for ribose. Some qualitative
and quantitative differences observed in the two types of macromolecules would be expected, considering their origins. The
results indicate that the actinomycete melanins have a qualitative sugar distribution pattern similar to that of the HAs from
Brazilian tropical soils and of HAs reported for soils from other climatic regions. The possible participation of actinomycete
melanins in the formation of soil humic substances is discussed.
Received: 4 April 1997 相似文献
933.
The tambaqui Colossoma macropomum is the most important native fish in Brazilian aquaculture. Females are almost 20% heavier than males and therefore are more profitable. Based on this information, we tested four different concentrations (20, 40, 80, and 120 mg/kg diet) of oestradiol (E2) offered during 6 weeks to tambaqui larvae and analysed their efficiency in producing female monosex batches of the species. The study was performed in two independent tests, using different genetic backgrounds (broodstocks). All treatments increased the percentage of females in the population, but only the highest E2 dose was “free” of males in both tests. All treated groups contained intersex individuals (when sex inversion is not complete). Plasmatic E2 concentration was similar between treated and non‐treated fish 60 days after the treatment in fish treated with 20, 40, and 80 mg E2/kg diet. However, tambaqui treated with a 120 mg E2/kg diet showed lower E2 plasma concentration in comparison with the control group. Last, we chlorinated the water to ensure the environmental integrity of the study. Three days after chlorination, the water was completely free of any oestradiol residue (analysed by high‐performance liquid chromatography). 相似文献
934.
Increasingly countries are seeking to reduce emission of greenhouse gases from the agricultural industries, and livestock production in particular, as part of their climate change management. While many reviews update progress in mitigation research, a quantitative assessment of the efficacy and performance-consequences of nutritional strategies to mitigate enteric methane (CH4) emissions from ruminants has been lacking. A meta-analysis was conducted based on 108 refereed papers from recent animal studies (2000–2020) to report effects on CH4 production, CH4 yield and CH4 emission intensity from 8 dietary interventions. The interventions (oils, microalgae, nitrate, ionophores, protozoal control, phytochemicals, essential oils and 3-nitrooxypropanol). Of these, macroalgae and 3-nitrooxypropanol showed greatest efficacy in reducing CH4 yield (g CH4/kg of dry matter intake) at the doses trialled. The confidence intervals derived for the mitigation efficacies could be applied to estimate the potential to reduce national livestock emissions through the implementation of these dietary interventions. 相似文献
935.
Ana Paula Lira de Souza Tamiris Henrique Ferreira Jos Luiz Pedreira Mourio Maurício Latera Martins Aimê Rachel Magenta Magalhaes Mnica Yumi Tsuzuki 《Aquaculture Nutrition》2020,26(3):964-977
This study evaluated the effect of exogenous digestive enzymes on the survival, growth performance and morphology of the digestive tract of juveniles of the longsnout seahorse Hippocampus reidi fed exclusively with Artemia and supplemented with five different concentrations of porcine pancreatin (PP) (0, 5, 25, 50 and 75 mg/L from birth until 30 days after release). The results found in the present study clearly show that there was a significant increase in survival and growth as well as substantial changes in the morphology of intestinal villi in seahorses fed exclusively with Artemia supplemented with 75 mg/L PP. Therefore, the use of digestive enzyme supplementation constitutes an important advance for the establishment of a more efficient and practical feeding protocol (exclusive use of Artemia) for juveniles of the longsnout seahorse. 相似文献
936.
937.
Jos Amorim Reis‐Filho 《Fisheries Management and Ecology》2020,27(2):155-166
Managing coastal resources sometimes requires looking into the past, as this provides a baseline against which present conditions may be gauged. The present study evaluated the circumstances that led Brazilian coastal fishers to modify their use of encircling gillnets. Other stressors (i.e. water pollution and habitat degradation) acted synergistically on the fisheries dynamic between 1950 and 2016. Declining catches of several species were observed through fishers' historical perception and through fisheries landing records. Three notable trends in net handling were associated with distinct historical periods. Specifically, pressures from modern fishery practices and gear (e.g. monofilament nets), the adoption of spiral setting arrangements and the increasing use of trammel nets appear responsible for the decline of many stocks. Mullet, seabass, jack and pilchard stocks decreased over time and were associated the changes witnessed in the encircling net operations. These changes occurred in response to overexploitation of fish stocks, to exploit the dwindling fisheries resources. The study also discusses the reasons leading fishers to accept how encircling gillnets ought to be used, their interpretation of such changes and the implications these changes have for fisheries management. 相似文献
938.
Gomes Lucas Carvalho Bianchi Felix J. J. A. Cardoso Irene M. Fernandes Filho Elpídio I. Schulte Rogier P. O. 《Landscape Ecology》2020,35(7):1571-1586
Landscape Ecology - Land use and land cover (LULC) changes may affect the provision of ecosystem services. However, little is known how LULC changes influence the spatio-temporal variation in... 相似文献
939.
L. Ferrand M. M. S. Almeida A. F. Orílio E. Dal Bó R. O. Resende M. L. García 《Plant pathology》2019,68(9):1587-1601
Tomato spotted wilt virus (TSWV) has been present in Argentina since 1938 and had limited sweet pepper and tomato production until the introduction of resistant cultivars bearing Tsw and Sw-5b genes. However, the wide use of TSWV-resistant pepper plants in La Plata Horticultural Belt (LPHB) triggered the emergence of resistance-breaking isolates (RB), increasing the economic impact of TSWV in pepper. This work characterized 11 natural RB pepper isolates from LPHB that have overcome the Tsw resistance gene in Capsicum sp. but are unable to break the Sw-5b-mediated resistance in tomato. Phylogenetic analysis of the N gene showed that the LPHB isolates are most closely related to isolates from Asia, indicating that Argentine TSWV isolates might have emerged from the Asian continent. The NSs sequence analysis reinforces the hypothesis that the appearance of an RB phenotype is a consequence of a number of different single amino acid substitutions spread along the NSs gene that lead to multiple independent evolutionary events. These results provide information on the current situation of the tospovirus–pepper/tomato pathosystems in LPHB, which represents a fundamental prerequisite to include these RB isolates in future screening programmes in order to select new and durable sources of resistance to TSWV in pepper. 相似文献
940.
Souza Danilo Santos Souza Jane Delane Reis Pimentel Coutinho Janclei Pereira da Silveira Tayse Ferreira Ferreira Ballus Cristiano Augusto Filho José Teixeira Bolini Helena Maria Andre Godoy Helena Teixeira 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(1):70-75
Plant Foods for Human Nutrition - Tamarind fruits are consumed worldwide and their seeds have an underexploited potential. We assessed the effect of the addition of a freeze-dried aqueous of... 相似文献