Underestimated role of legume roots for soil N fertility

Research ArticleNitrogen (N) is a major fertilizing element for plants. The distribution of N in legumes is influencing the efficiency of the next crop. Nitrogen storage in legumes is actually estimated by N fixation in shoots, whereas there is little knowledge on the contribution of roots and nodules to legume N and soil N. Here, we studied the contribution of roots and nodules of grain and pasture legumes to plant N and soil N in Mediterranean fields. Experiments were run under rainfed conditions for a 2-year period in three regions of Portugal. Entire plants including top plant and visible roots and nodules were sampled at the end of the growing seasons for grain legumes, sweet and yellow lupine, and over two harvests in case of pastures. N2 fixation was measured for grain legumes and pasture legumes using 15N tracing. Our results show that aboveground N concentration did not vary among legumes, but differed in the belowground tissues. Field studies show that 7–11%of total legume N was associated with roots and nodules. Data also show an allocation of 11– 14 kg N fixed t−1 belowground dry matter in indeterminate legumes, which represents half the amount of total aboveground plant. This finding demonstrates that investigation relying only on shoot Nunderestimates the role of legumes for soil N fertilityinfo:eu-repo/semantics/publishedVersio

Nitrogen fertilization on growth and productivity of young 'Rocha' pear trees

Pear trees (Pyrus communis L. ‘Rocha’) grafted on quince ‘BA29’ were planted in February of 2003 at “Pêro Moniz” (“Cadaval”, Portugal) and drip-fertigated for three years with four N levels (0, 10, 20 and 40 kg N/ha per year) using ammonium nitrate. At planting and at the end of each season, tree height (A), trunk cross sectional area (AST) and the number of shoots and shoot length (NL and CL) were determined. Leaves were collected 110 days after full bloom (DAPF) and at leaf fall and were chemically analysed for N. The onset of flowering was in 2005 and in that year the fruit set and the yield characteristics were evaluated. Moreover, in 2005 five extra trees were selected for each N level, and all flowers were collected and analysed. Most growthcharacteristics were irresponsive to N fertilization. In the third year the AST differed between N levels, whereas CL responded to N supply at the end of the first year of fertilization. The leaves N concentration varied in response to N supply. The control presented fewer flowers and the highest N level resulted in a greater flower production. Flower N concentration was lower at the intermediate N levels. Fruit set and yield were not significantly different between N treatments. Fruits from the highest N level presented lower pulp firmness and a bigger starch regression index, indicating a more advanced maturation stage than the fruits from other N levels

O cultivo do arroz e a resposta do agrossistema às alterações ambientais de temperatura e dióxido de carbono

A cultivar de arroz Ariete apresentou uma eficiência máxima de uso do N de 64% e uma produção de 8,5 t ha-1, após aplicação de 120 kg N ha-1, metade em fundo e metade ao afilhamento. Os fatores de emissão de GEEs medidos no campo foram de 136 kg CH4 ha-1 e 1,5% para o N2O. As emissões de COVs (especialmente na forma de terpenos) e NH3 foram reduzidas, mas atingiram 8 kg N-NH3 ha-1 dia-1 após a adubação de cobertura.FCT - projeto PTDC/AGR-AAM/102529/2008

High resolution human leukocyte antigen (HLA) class I and class II allele typing in Mexican mestizo women with sporadic breast cancer: case-control study

<p>Abstract</p> <p>Background</p> <p>The development of breast cancer is multifactorial. Hormonal, environmental factors and genetic predisposition, among others, could interact in the presentation of breast carcinoma. Human leukocyte antigen (HLA) alleles play an important role in immunity (cellular immunity) and may be important genetic traits. HLAAllele-specific interaction has not been well established. Recently, several studies had been conducted in order to do so, but the results are controversial and in some instances contradictory.</p> <p>Methods</p> <p>We designed a case-control study to quantify the association of HLA class I and II genes and breast cancer. HLA typing was performed by high resolution sequence-specific oligotyping after DNA amplification (PCR-SSOP) of 100 breast cancer Mexican mestizo patients and 99 matched healthy controls.</p> <p>Results</p> <p>HLA-A frequencies that we were able to observe that there was no difference between both groups from the statistical viewpoint. HLA-B*1501 was found three times more common in the case group (OR, 3.714; <it>p </it>= 0.031). HLA-Cw is not a marker neither for risk, nor protection for the disease, because we did not find significant statistical differences between the two groups. DRB1*1301, which is expressed in seven cases and in only one control, observing an risk increase of up to seven times and DRB1*1602, which behaves similarly in being present solely in the cases (OR, 16.701; 95% CI, 0.947 – 294.670). DQ*0301-allele expression, which is much more common in the control group and could be protective for the presentation of the disease (OR, 0.078; 95% CI, 0.027–0.223, <it>p </it>= 0.00001).</p> <p>Conclusion</p> <p>Our results reveal the role of the MHC genes in the pathophysiology of breast cancer, suggesting that in the development of breast cancer exists a disorder of immune regulation. The triggering factor seems to be restricted to certain ethnic groups and certain geographical regions since the relevant MHC alleles are highly diverse. This is the first study in Mexican population where high resolutions HLA typing has been performed in order to try to establish an association with malignancy.</p

Plant–Rhizobium symbiosis, seed nutraceuticals, and waste quality for energy production of Vicia faba L. as affected by crop management

Background: Broad bean fits sustainable agriculture model due to symbiosis with Rhizobium, the seeds being a good source of energy, proteins, polyphenols, and fiber. The large amount of broad bean biomass residues can be employed for biofuel production, thus valorizing the overall production process. This research was aimed to investigate on the effects of farming management, such as greenhouse cultivation and appropriate planting time on the qualities of broad bean seeds and residual biomass for conversion into biofuel. The related balances of energy gain associated to both ethanol yield and nitrogen fertilizer saving due to Rhizobium nitrogen fixation were assessed. Methods: Research was carried out on broad bean in Portici, province of Naples, southern Italy, based on the factorial combination of two farming systems (open field, greenhouse) and five planting times: 27 September and 11 October, to obtain early production; 25 October, which fell in the usual period for broad bean planting in the province area; and 8 November and 22 November, for late production. For each of these cultivation conditions, the quality of seeds, in terms of protein, fiber and antioxidant concentrations, and of crop residual biomass were determined. In addition, the energy yield as ethanol production from residual biomass and nitrogen fertilizer saving due to Rhizobium atmospheric fixation were assessed. Results and discussion: The highest plant nitrogen uptake was recorded under the fourth planting time in open field and the third in greenhouse, the average accumulation attaining 87% in residual biomass, 7.4% in pods, and 5.6% in seeds. Seed protein content was 12.6% higher in greenhouse than in open field and 16.2% higher under the latest planting time compared to the earliest one. Seed polyphenol concentration was higher in open field than in greenhouse and with the two earliest planting times. Greenhouse grown biomass showed higher values of lignin, hemicellulose and pectin, compared to open field, whereas the opposite trend was for cellulose. Lignin showed a decrease from the first to the last crop cycle, opposite to cellulose, and glucose was the most represented monosaccharide. Both the highest theoretical ethanol and overall energy production were highest with the fourth planting time. Conclusions: Greenhouse management enabled broad bean plants to accumulate higher proteins in seeds, but open field conditions resulted in better residual biomass quality for ethanol and Rhizobium-depending energy production

Sustainable agriculture in Europe and quality of the products

info:eu-repo/semantics/publishedVersio