Showing papers by "André Rodrigues dos Reis published in 2018"

Hidden Nickel Deficiency? Nickel Fertilization via Soil Improves Nitrogen Metabolism and Grain Yield in Soybean Genotypes.

Abstract: Nickel (Ni)-a component of urease and hydrogenase-was the latest nutrient to be recognized as an essential element for plants. However, to date there are no records of Ni deficiency for annual species cultivated under field conditions, possibly because of the non-appearance of obvious and distinctive symptoms, i.e., a hidden (or latent) deficiency. Soybean, a crop cultivated on soils poor in extractable Ni, has a high dependence on biological nitrogen fixation (BNF), in which Ni plays a key role. Thus, we hypothesized that Ni fertilization in soybean genotypes results in a better nitrogen physiological function and in higher grain production due to the hidden deficiency of this micronutrient. To verify this hypothesis, two simultaneous experiments were carried out, under greenhouse and field conditions, with Ni supply of 0.0 or 0.5 mg of Ni kg-1 of soil. For this, we used 15 soybean genotypes and two soybean isogenic lines (urease positive, Eu3; urease activity-null, eu3-a, formerly eu3-e1). Plants were evaluated for yield, Ni and N concentration, photosynthesis, and N metabolism. Nickel fertilization resulted in greater grain yield in some genotypes, indicating the hidden deficiency of Ni in both conditions. Yield gains of up to 2.9 g per plant in greenhouse and up to 1,502 kg ha-1 in field conditions were associated with a promoted N metabolism, namely, leaf N concentration, ammonia, ureides, urea, and urease activity, which separated the genotypes into groups of Ni responsiveness. Nickel supply also positively affected photosynthesis in the genotypes, never causing detrimental effects, except for the eu3-a mutant, which due to the absence of ureolytic activity accumulated excess urea in leaves and had reduced yield. In summary, the effect of Ni on the plants was positive and the extent of this effect was controlled by genotype-environment interaction. The application of 0.5 mg kg-1 of Ni resulted in safe levels of this element in grains for human health consumption. Including Ni applications in fertilization programs may provide significant yield benefits in soybean production on low Ni soil. This might also be the case for other annual crops, especially legumes.

The Molecular Genetics of Zinc Uptake and Utilization Efficiency in Crop Plants

Abstract: Zinc (Zn) is an essential micronutrient for plant growth and development, and its deficiency in plants has been widely reported in many regions of the world. About 50% of soil used for agriculture contain a low level of plant-available Zn, which reduces not only yield but also nutritional quality of grains and derivatives. Under these conditions, the Zn utilization efficiency (ZnUE) of plants is essential for food crops and human health. Zn uptake and ZnUE by plants is complex, as each step, including root and foliar uptake, assimilation, translocation, and remobilization are governed by multiple interacting environmental and genetic factors. Zinc transportation from roots to shoots occurs through the xylem and is then easily retranslocated by phloem. The Zn uptake into cells and its permeability into and out of intracellular organelles require some of the specific chemicals generally known as transporter proteins. These proteins possess a quality to span the cell membranes that facilitate the movement of Zn. A number of metal transporters have been identified in plants, including the P1B-ATPase family, zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP), natural resistance-associated macrophage protein (NRAMP) family, and cation diffusion facilitator (CDF or MTP) family. This manuscript critically reviews about Zn transport pathway, molecular genetic driving the Zn uptake, and Zn utilization efficiency in several crop plants.

Impact of foliar nickel application on urease activity, antioxidant metabolism and control of powdery mildew (Microsphaera diffusa) in soybean plants

Abstract: J. P. Q. Barcelos, H. P. G. Reis, C. V. Godoy, P. L. Grat~ ao, E. Furlani Junior, F. F. Putti, M. Campos and A. R. Reis* S~ ao Paulo State University – UNESP, Ilha Solteira, SP, 15385-000; Embrapa Soybean, Rodovia Carlos Jo~ ao Strass – Distrito de Warta, Londrina, 86001-970, PR; S~ ao Paulo State University – UNESP, Jaboticabal, 79560-000, SP; and S~ ao Paulo State University – UNESP, Tup~ a, 17602-496, SP, Brazil

Response of brachiaria grass to selenium forms applied in a tropical soil

Abstract: In Brazil the total area of native and cultivated pasture used for livestock is around 180 million hectares, and selenium (Se) is absent from mineral fertilizer formulas. Nutritional supplementation of this element takes place along with provision of mineral salts in the form of sodium selenite. In the present work, the effects of adding selenate and selenite on Se biofortification, antioxidant activity and anatomy alterations in Brachiaria brizantha were evaluated. The experiments were disposed in a completely randomized design in a 6 × 2 factorial scheme, by means of five levels of Se (0; 0.5; 1.0; 3.0 and 6.0 mg/kg) applied along with grass plant fertilizer, and two Se forms (sodium selenate and sodium selenite), with six replications. The results of the present study suggest that, in tropical soil conditions, the application of Se as selenate at low doses is more appropriate for B. brizantha biofortification than Se as selenite, because it favors a greater shoot Se levels, better activation of the antioxidant system and reduces on lipid peroxidation. Finally, with an increase of Se rates, cellular modifications were observed in internal structures of roots in B. brizantha, with aerenchyma appearing.