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131.
Robson Thiago Xavier de Sousa Gaspar Henrique Korndörfer 《Journal of plant nutrition》2013,36(8):1103-1111
There is little information about the best silicon (Si) sources for agricultural use, and yet some products have already been marketed as sources of this element. One of these products is slag, which is used as a source for Si and lime. This study evaluated the silicon supply availability and efficacy of different silicate slag types for rice crops. The experiment was conducted in a greenhouse, used Entisol Quatzipsamment soil and was set up in randomized blocks with three replications. Si source reactivity was evaluated using five metallurgic slag types and Wollastonite, which is considered a standard in Si studies. Doses of each Si source were 1000 and 2000 mg dm?3 of Si and a control (additional treatment). Soil data [soluble Si, calcium (Ca2+), magnesium (Mg2+) and pH] and rice growth and yield were recorded. Data were evaluated by analysis of variance and contrasts were made for comparisons between each slag type and the additional treatment. Averages were compared by the Scott Knott test at 5% with the statistics program SISVAR. The efficacy of the slag types in supplying Si for the plants (ESSi) and in increasing Si availability in the soil (ESiA) was determined from the values of contrast estimates. Slag E3 and Wollastonite were effective in increasing soil silicon availability and, consequently, the efficacy of supplying silicon for the plants, while the other slag types had low efficacy. 相似文献
132.
Aluminum toxicity and related nutrient deficiencies, such as phosphorus deficiency, are considered to be major environmental constraints on food production world wide (Foy 1983). Toxic effects of Al in cells are characterized by the inhibition of cell division (Morimura et al. 1978) and nuclear activity (Matsumoto et al. 1977). Therefore, a plant cell culture system could be used as a model system for the physiological study of aluminum toxicity in higher plants. For such a study, it is important to initially define the factors affecting cell responses to aluminum toxicity. 相似文献
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135.
Clever Briedis João Carlos de Moraes Sá Eduardo Fávero Caires Jaqueline de Fátima Navarro Thiago Massao Inagaki Adriane Boer Caio Quadros Neto Ademir de Oliveira Ferreira Lutécia Beatriz Canalli Josiane Burkner dos Santos 《Geoderma》2012
The stabilisation of soil organic matter (SOM) is the result of the simultaneous action of three mechanisms: chemical stabilisation, biochemical stabilisation and physical protection. The objectives of this study were (i) to evaluate carbon-protection mechanisms in different SOM pools in soil aggregates and (ii) to identify the association of Ca2 + with total organic carbon (TOC) under the influence of surface liming in a medium-textured Oxisol in a long-term experiment under no-till system (NTS) in southern Brazil (25° 10′ S, 50° 05′ W). The treatments consisted of application of zero or 6 tons ha? 1 of dolomitic lime on the soil surface in 1993 and a reapplication of zero or 3 tons ha? 1 of dolomitic lime in 2000 to plots with or without previous lime application. Soil samples collected at depths of 0–2.5, 2.5–5, 5–10 and 10–20 cm were separated into seven aggregate classes. In each of these classes, TOC, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) were analysed. The 8–19 mm sized aggregates from the 0–2.5 cm layer were assessed by energy-dispersive X-ray spectroscopy (EDS) for the elemental analysis of carbon (C) and calcium (Ca). The liming caused an accumulation of TOC in the aggregates, mainly at a depth of 0–2.5 cm. The aggregates from soils treated with lime had a higher mean weight diameter (MWD) that resulted in the accumulation of TOC, especially in the 8–19 mm aggregate class, that was linear and closely related with C input (R2 = 0.99). The proportion of large aggregates in the treatments with lime was closely correlated with the TOC content of the whole sample. The largest dose of lime (9 tons ha? 1) resulted in higher TOC, POC and MAOC values, mainly in the 8–19 mm aggregate class. The elemental analyses for C and Ca revealed similar spectra between them for the surface-liming treatments in the clay fraction found in the centres of the 8–19 mm aggregates. The surface application of lime to NT fields provided greater stability and protection of the intra-aggregate C, presumably due to Ca2 + acting as a cationic bridge between OC and the kaolinite in the clay fraction. 相似文献
136.
Ayodele Ebenezer Ajayi Moacir de Souza Dias Junior Nilton Curi Cezar Francisco Araujo Junior Thiago Tadeu Teixeira Souza Alberto Vasconcellos Inda Junior 《Soil & Tillage Research》2009,105(1):122-127
In this study, strength attributes and compaction susceptibility of the main classes of Brazilian Latosols (Oxisols), under native vegetation, were studied using the load bearing capacity models relating precompression stress, compression index and water potential through statistical regression models. These models were developed based on the results of the analysis of undisturbed soil samples collected at the B horizon at the different sites. The results showed that the maximum value of the compression index was 0.53 for the Acric Red Latosol, indicating its higher susceptibility to soil compaction. The Dystrocohesive Yellow Latosol had the highest load bearing capacity, while the Acric Red Latosol had the lowest one. The Dystrocohesive Yellow Latosol due to its high load bearing capacity and bulk density (mechanical resistance) behave similarly to hardsetting soil, in which the plants root system has severe physical restrictions to explore deeper horizons during the dry periods. Differences in the load bearing capacity and compaction susceptibility were found to be influenced by soil structure which is associated with clay mineralogy in these very weathered-leached soils and water potential. The study also showed that soil compression index is influenced by water potential and clay mineralogy also. Our work has laid a foundation for estimation of compaction susceptibility of Latosols. 相似文献
137.
Wesley Dáttilo Rodrigo L. Martins Vera Uhde Janaína C. Noronha Fernando P. Florêncio Thiago J. Izzo 《Agroforestry Systems》2012,85(1):105-111
The fruit production of flowering plants critically depends on the pollination services provided by animals that compete for flower resources. The output of competitive interactions between ants and bees for inflorescences of jambolan Syzygium jambolanum (Myrtaceae) in an agroforestry system in Brazilian Meridional Amazonian are an interesting system of investigation due the possibility to control variables experimentally. In 20 S. jambolanum individuals we performed 300 treatments in different inflorescences of two strata (upper and lower) as follows: (1) ants exclusion, (2) bees exclusion, and (3) control group where ants and bees could access the inflorescences. There was no difference in the number of inflorescences, volume of nectar and sugar concentration between the strata. Also the visitors considered are distributed equally in the tree??s stratum. When bees were prevented from access the inflorescences, ants dominated more inflorescences only in the lower stratum. On the contrary, when ants were excluded, bees visited more inflorescences only in the upper stratum. We conclude that ants prevent the access to bees and vice versa as the result of different ability of resource utilization and foraging strategies. Thus, preventing the access of ants to the floral nectar could increase the level of nectar available to pollinators of S. jambolanum, thereby increasing productivity and reducing economic losses. 相似文献
138.
Kyoko Suzuki Tsutomu Suzuki Yukio Takahashi Mitsuhiro Okimoto Tetsuo Yamada Noriyasu Okazaki Yuichi Shimizu Masashi Fujiwara 《Journal of Wood Science》2009,55(1):60-68
The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca
1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion
into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni
4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen
at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations
confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil
and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium
is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature
region where oil was no longer produced.
Part of this study was presented at the 14th Annual Meeting of the Japan Institute of Energy, Suita, August 2005, and at the
18th Symposium, Session D, of the Materials Research Society of Japan, Tokyo, December 2007 相似文献
139.
Roberto A. Sá Francis S. Gomes Thiago H. Napoleão Nataly D. L. Santos Carla M. L. Melo Norma B. Gusmão Luana C. B. B. Coelho Patrícia M. G. Paiva Lothar W. Bieber 《Wood Science and Technology》2009,43(1-2):85-95
The aim of this work was to isolate a lectin from Myracrodruon urundeuva heartwood and to evaluate its antimicrobial activity against bacteria and fungi that attack plants, including woods. The lectin was isolated from heartwood through affinity chromatography on a chitin column monitored by hemagglutination assay. The lectin inhibited Gram-negative and Gram-positive bacteria and was more effective than antifungal Cercobin in growth inhibition of phytopathogenic fungi. The detected antimicrobial activity reveals the possible role of the lectin in the resistance of M. urundeuva heartwood against deteriorative biological agents. The M. urundeuva lectin is the first bioactive peptide found in heartwood, probably stored as a chemical protection against biodegradation. 相似文献
140.
Ana Murcia-Meseguer Thiago J. S. Alves Flor Budia Antonio Ortiz Pilar Medina 《Phytoparasitica》2018,46(2):233-245
We evaluated the chemical composition of thirteen commercially available plant essential oils and their insecticidal activity against the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Gas chromatography-mass spectrometry was used to characterize the chemical components of the essential oils. A total of 113 compounds were identified, with terpenes (>80%) and aromatic compounds as primary constituents. The toxicity of each pure essential oil was tested separately on third instar larvae and adult beet armyworms by topical application of 0.5 μl oil/ insect. All plant essential oils were found to be harmful to S. exigua, with third instar larvae showing significantly more susceptibility than adults. Essential oils of Cinnamomum zeylanicum and Juniperus virginiana showed the highest toxicity (mortality above 90%) to larvae, while C. zeylanicum and Pogostemon cablin oils were the most harmful compounds (95% mortality) to adults. Cymbopogon winterianus oil caused delayed mortality (similar to the effects of insect growth regulators) as well as malformations in pupae. C. winterianus, Ocimum basilicum and Rosmarinus officinalis oils significantly reduced fecundity, whereas no significant effects were observed on fertility. 相似文献