Ana Rosa Ribeiro Bastos

Lycopersicon esculentum submitted to Cd-stressful conditions in nutrition solution: Nutrient contents and translocation.

The increasing number of cases on soil contamination by heavy metals has affected crop yields, besides representing an imminent risk to food. Some of these contaminants, such as cadmium, are very similar to micronutrients and thus more easily absorbed by the plants. This study assessed the effect of increasing amounts of cadmium on the content and translocation of micro and macronutrients in tomato. Tomatoes were grown in Clarks nutrient solution and subjected to increasing levels of Cd: 0, 0.025, 0.1, 0.5 and 1.0mg L(-1). The plants contaminated by cadmium had a maximum reduction in the aerial part compared to the control of: 2.25g kg(-1), 2.80g kg(-1), 18.93mg kg(-1) and 14.15mg kg(-1) for K, Ca, Mn and Zn, respectively. In other parts of the tomato were reduced from 2.3g kg(-1) K in fruits and 280.5mg kg(-1) of Mn in the roots. In addition to changes in the levels of some nutrients, the restricted Cd translocation in 1.15 percent P and 2.8 percent Cu to shoots compared to control, but did not affect the translocation of K, Ca, Mg and Zn.

DOSES DE GESSO EM CAFEEIRO: INFLUÊNCIA NOS TEORES DE CÁLCIO, MAGNÉSIO, POTÁSSIO E pH NA SOLUÇÃO DE UM LATOSSOLO VERMELHO DISTRÓFICO

Unbalanced amounts of Ca2+, Mg2+ and K+ in soils as a consequence of high gypsum applications can be due to the relationship in size (ionic radius) and charge density (charge/ionic radius) of each ionic species. The higher the ionic strength, the stronger is the bonding of these cations with the opposite charge ions such as OH-, SO4-2. Thus, excessive gypsum applications, disregarding the charge balance of the soil colloidal system, the ionic balance of the solution, and the CEC, can result in significant leaching of these nutrients throughout the soil profile. The aim of this study was to evaluate the effect of high gypsum rates (0, 7, and 56 t ha-1) on the pH and Ca2+, Mg2+, and K+ contents in aqueous soil extracts of a dystrophic Red Latosol with coffee. The soil was sampled in the coffee rows in the following depths: 0.15-0.25; 0.35-0.45; 0.75-0.85; 1.15-1.25, and 2.35-2.45 m, 16 months after gypsum application. The experiment consisted of four treatments: G-0 - 2 t ha-1 of gypsum was applied in total area during soil preparation, with brachiaria between coffee rows; G-7 - same as in G-0 plus 7.0 t ha-1 of gypsum applied to the coffee rows; G-56 - same as in G-0 plus 56 t ha-1 of gypsum applied to the coffee rows; and CV-7 - same as in G-7 but without brachiaria between the coffee rows. The experiments were conducted in triplicate, in a randomized block design. After 16 months, there was a reduction of the pH of the soil solution in the layers 0.15-0.25, 0.35-0.45, and 0.75-0.85 m. Gypsum improved the root environment in deeper layers, increasing Mg2+ and Ca2+ concentrations in the soil solution, but reduced K+ below 0.85 m. The amounts of exchangeable Ca2+ and Mg2+ found in the soil solution were above the critical level while exchangeable K+ was within the range indicated for the crop.

Recycling of solid waste rich in organic nitrogen from leather industry: mineral nutrition of rice plants.

The leather industry produces a large quantity of solid waste (wet blue leather), which contains a high amount of chromium. After its removal from wet blue leather, a solid collagenic material is recovered, containing high nitrogen levels, which can be used as a nitrogen source in agriculture. In order to take more advantage of the collagen, it was enriched with mineral P and K in order to produce NPK formulations. The objective was also to evaluate the efficiency of such formulations as a nutrient supply for rice plants in an Oxisoil, under greenhouse conditions. The application of PK enriched-collagen formulations resulted in N contents in the vegetative parts and grains of rice plants which were equivalent or superior to those obtained with urea and commercial NPK formulations.

Leather industry solid waste as nitrogen source for growth of common bean plants.

The leather industry generates large amounts of a Cr-containing solid waste (wet blue leather). This material is classified by the Brazilian Environmental Council as a category-one waste, requiring a special disposal. The patented process Br n. PI 001538 is a technique to remove chromium from wet blue leather, with the recovery of a solid collagenic material (collagen), containing high nitrogen levels. This work aimed to evaluate the residual effect of soil application of collagen on the production of dry matter, content and accumulation of N in common bean plants (Phaseolus vulgaris L.), after the previous growth of elephantgrass (Pennisetum purpureum Schumach.) cv. Napier, as well as to quantify the mineralization rate of N in the soil. The application of collagen, at rates equivalent to 16 and 32 t , provided greater N contents in the common bean plants, indicating residual effect of these rates of application; the same was observed for the rates of 4 and 8 t , though in smaller proportions. Higher mineralization rates of N collagen occurred next to 16 days after soil incubation. During the 216 days of incubation, the treatments with collagen showed higher amounts of mineralized nitrogen.

Incorporation of mineral phosphorus and potassium on leather waste (collagen): A new NcollagenPK-fertilizer with slow liberation

The feasibility of using a solid waste (rich in nitrogen) from the leather industry, after chromium extraction, as adsorbent for P and K, for possible utilization as NPK fertilizer was evaluated. The materials, with and without the addition of P and K, were characterized by chemical analyses, infrared spectroscopy, EDS (energy dispersive X-ray spectrometry) and SEM (scanning electronic microscopy). Langmuir and Freundlich equations were used for analyzing the experimental data, which showed a better fit to the Freundlich model, thus suggesting a multilayer adsorption process on the surface of the adsorbent. A preliminary test in greenhouse demonstrates that the P and K incorporation on the matrix rich in nitrogen (collagen) is a interesting alternative to use such material as NPK fertilizer. The application of N(collagen)PK formulations, as a source of nutrients for the growth of rice plants, showed promising agronomic results.

Produção de matéria seca, teor e acúmulo de silício em cultivares de arroz sob doses de silício

O efeito do silicio (Si) na producao de materia seca de arroz, teor e acumulo de Si foi avaliado sob condicoes de casa-de-vegetacao. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 5 x 2 com 4 repeticoes. Os tratamentos foram 5 doses de Si (0; 0,25; 0,50; 0,75 e 1,00 g dm-3) e 2 cultivares de arroz (Conai e Curinga). A aplicacao de Si nao afetou os componentes de crescimento e producao, com excecao da materia seca de raiz. Houve um acrescimo da materia seca de raiz sob aplicacao de Si com uma producao maxima de 33,57 g vaso-1 na dose ajustada de 0,38 g dm-3 de Si. O acumulo e os teores de Si variaram entre os cultivares, os quais responderam de forma linear ao aumento das doses de Si. Ja para o acumulo de Si na parte aerea nao houve diferencas significativas entre cultivares.

Effects of Lead on the Content, Accumulation, and Translocation of Nutrients in Bean Plant Cultivated in Nutritive Solution

Increasing contents of lead (Pb; from 0 to 10 mg L−1) as contaminant were added in Clarks nutritive solution to evaluate the effects on content, accumulation, and translocation of macronutrients [phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)] and micronutrients [copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe)] in different parts of the bean plant (Phaseolus vulgaris L.). Experiments were built using an entirely randomized statistical arrangement and measurements were performed after 60 days of exposure to Pb. The contents of almost all nutrients decreased when Pb was added, except for P in root, Mg in fruits, and S in root and fruits. Reduction in accumulation of all nutrients in the three parts of plants was determined, and an increase in the translocation index was observed for the following nutrients: Mg and Zn in fruits and S in fruits and leaves. For the remaining nutrients, the translocation index diminished.

Effects of Cadmium and Lead on Plant Growth and Content of Heavy Metals in Arugula Cultivated in Nutritive Solution

A greenhouse assay using an arugula (Eruca sativa L.) hydroponics system was carried out to evaluate the following effects of increasing amounts of cadmium and lead in nutritive solution: (a) production; (b) translocation of cadmium (Cd) and lead (Pb) throughout the plants; (c) possible interactions of Cd and Pb with other mineral elements, transition metals, essential to plants; (d) tolerance limits to Cd and Pb with regard to production; and (e) chelating interaction of Cd and Pb with root substances. The absorption of Cd and Pb increased with increasing dosages in solution. Roots accumulated larger amounts of metals than shoots. Plants develop better with less than 0.025 mg L−1 of Cd, with a damaging Cd concentration of 1 mg L−1. The tolerable Pb concentration was up to 10 mg L−1. Cadmium and Pb translocate poorly in plants and their deleterious effect is due to the deposit of very stable chelates in roots.

Métodos de extração para quantificação de manganês disponível em fertilizantes

The solubility of Mn in different fertilizers (MnSO4.H2O-p.a., MnO2-p.a.+MnO-Ind., MnO2-Ind.+MnO-Ind., MnO2-p.a., MnO2-Ind. and MnO-Ind.) was determined using different methodologies: total content and soluble contents in water, 10% H2SO4, citric acid at 20 g L-1, diluted neutral ammonium citrate, (1+9) and DTPA at 0.005 mol L-1. The Mn solubilities in the latter three extractors were assessed after agitation of the sample for one hour and after boiling for 5 minutes. The extraction procedure using neutral ammonium citrate (1+9), at 1:100, with agitation for one hour, was shown to be the most adequate to assess the availability of Mn in fertilizers.

Métodos de extração para quantificação de cobre disponível em fertilizantes

Neste estudo, determinou-se a solubilidade do Cu em diferentes fertilizantes e avaliou-se sua correlacao com a absorcao deste micronutriente por plantas de arroz (Oryza sativa L.). Utilizaram-se as seguintes fontes: mistura de oxido cuprico p.a. e Cu metalico moido p.a.; oxido de Cu 40 Ind.; sulfato de Cu p.a.; minerio calcopirita; Cu metal moido p.a. e oxido cuprico p.a. Foram determinados o teor total de Cu e os teores de Cu soluvel em agua e em solucoes de acido citrico a 20 g L-1, de citrato neutro de amonio (1 + 9) e de DTPA 0,005 mol L-1. As solubilidades nesses tres ultimos extratores foram determinadas por agitacao da amostra por uma hora e por fervura durante cinco minutos. Paralelamente, foram realizados experimentos em casa de vegetacao, com cultivos sucessivos da cultura do arroz, para verificar os efeitos imediato e residual da aplicacao das fontes de Cu em diferentes doses (0; 0,75; 1,5 e 3 mg dm-3 de Cu) em um Neossolo Quartzarenico ortico. Os fertilizantes apresentaram solubilidade diferenciada, sendo diferente tambem com relacao ao teor total de Cu. Todas as fontes testadas foram eficientes no fornecimento desse elemento as plantas, embora doses mais elevadas sejam necessarias quando se usam as fontes minerio calcopirita e oxido de Cu 40 Ind. As fontes apresentaram efeito residual de Cu no solo apos o segundo cultivo das plantas de arroz. Diante das varias fontes com Cu e das diferencas entre elas com relacao a solubilidade e eficiencia agronomica, sugere-se a adocao de mais um tipo de garantia para o micronutriente alem do teor total. O citrato neutro de amonio (1 + 9), na relacao 1:100, com fervura por cinco minutos, mostrou-se adequado para determinacao do teor de Cu disponivel em fertilizantes.