Silvio Junio Ramos

Fibra de coco e resíduo de algodão para substrato de mudas de tomateiro

A greenhouse experiment was carried out to evaluate fiber mixture of coconut and cotton waste, to produce substrate for tomato seedling production (cultivar Kada Gigante). The experimental design was randomized blocks, four replications, with seven treatments: T1) Commercial Substrate Hortimix®; T2) 0% coconut dry fiber mass (FC)+100% dry mass of cotton waste (RA); T3) 20% (FC)+80% (RA); T4) 40% (FC)+60% (RA); T5) 60% (FC)+40% (RA); T6) 80% (FC)+20% (RA); T7) 100% (FC)+0% (RA). The vigor was evaluated in terms of percentage and index of emergence, stem diameter, seedling height. Increasing the proportion of coconut fiber to cotton waste ratio resulted in an increase of percentage and index of emergence; however, the stem diameter, seedling height, shoot and root fresh and dry mass decreased. The residue of cotton proceeding from the compostage of residues of the textil factory, constitutes in a useful material in the commercial substrate production.

Assessment of the Anticancer Compounds Se-Methylselenocysteine and Glucosinolates in Se-Biofortified Broccoli (Brassica oleracea L. var. italica) Sprouts and Florets

Broccoli (Brassica oleracea L. var. italica) is a rich source of chemopreventive compounds. Here, we evaluated and compared the effect of selenium (Se) treatment on the accumulation of anticancer compounds Se-methylselenocysteine (SeMSCys) and glucosinolates in broccoli sprouts and florets. Total Se and SeMSCys content in sprouts increased concomitantly with increasing Se doses. Selenate was superior to selenite in inducing total Se accumulation, but selenite is equally effective as selenate in promoting SeMSCys synthesis in sprouts. Increasing sulfur doses reduced total Se and SeMSCys content in sprouts treated with selenate, but not in those with selenite. Examination of five broccoli cultivars reveals that sprouts generally have better fractional ability than florets to convert inorganic Se into SeMSCys. Distinctive glucosinolate profiles between sprouts and florets were observed, and sprouts contained approximately 6-fold more glucoraphanin than florets. In contrast to florets, glucosinolate content was not affected by Se treatment in sprouts. Thus, Se-enriched broccoli sprouts are excellent for simultaneous accumulation of chemopreventive compounds SeMSCys and glucoraphanin.

Produção de mudas de tomateiro em substratos contendo fibra de coco e pó de rocha

ABSTRACT Tomato seedlings production using substrates with coconutfiber and rock waste A greenhouse experiment was carried out to evaluate the ratioof coconut fiber and rock waste, in the tomato seedling production(cultivar Kada Gigante), in Montes Claros, Brazil. The experimentaldesign was of randomized complete blocks with four replicates. Thetreatments were composed of a control and six ratios of coconutfiber (FC) and rock waste (RG): T 1 - Commercial SubstrateHortimix ® ; T 2 - 0% FC + 100% RG; T 3 - 20% FC + 80% RG; T 4 -40% FC + 60% RG; T 5 - 60% FC + 40% RG; T 6 - 80% FC + 20%RG; T 7 - 100% FC + 0% RG. The cultivation was done in polystyrenetrays with cells of 3.5 x 3.5 x 5,0 cm. Stem diameter, seedling height,emergency speed index, emergency percentage, root and aerial partof fresh and dry matter were evaluated. In almost all the evaluatedcharacteristics the commercial substrate was better than the substratescontaining coconut fiber and rock waste. Among the substratescontaining coconut fiber and rock waste, the seedlings with bettercharacteristics were obtained with a mixture of approximately 70%of the volume of coconut fiber.

Rare Earth Elements in the Soil Environment

Rare earth elements (REE) are a homogenous group of 17 chemical elements in the periodic table that are key to many modern industries including chemicals, consumer electronics, clean energy, transportation, health care, aviation, and defense. Moreover, in recent years, they have been used in agriculture. One of the consequences of their worldwide use is the possible increase of their levels in various environmental compartments. This review addresses major topics concerning the study of REE in the soil environment, with special attention to the latest research findings. The main sources of REE to soils, the contents of REE in soils worldwide, and relevant information on the effects of REE to plants were explored. Ecological and human health risk issues related to the presence of REE in soils were also discussed. Although several findings reported positive effects of REE on plant growth, many questions about their biological role remain unanswered. Therefore, studies concerning the actual mechanism of action of these elements on cellular and physiological processes should be further refined. Even more urgent is to unveil their chemical behavior in soils and the ecological and human health risks that might be associated with the widespread use of REE in our modern society.

Bioaccumulation and effects of lanthanum on growth and mitotic index in soybean plants.

Rare earth elements such as lanthanum (La) have been used as agricultural inputs in some countries in order to enhance yield and improve crop quality. However, little is known about the effect of La on the growth and structure of soybean, which is an important food and feed crop worldwide. In this study, bioaccumulation of La and its effects on the growth and mitotic index of soybean was evaluated. Soybean plants were exposed to increasing concentrations of La (0, 5, 10, 20, 40, 80, and 160 µM) in nutrient solution for 28 days. Plant response to La was evaluated in terms of plant growth, nutritional characteristics, photosynthetic rate, chlorophyll content, mitotic index, modifications in the ultrastructure of roots and leaves, and La mapping in root and shoot tissues. The results showed that the roots of soybean plants can accumulate sixty-fold more La than shoots. La deposition occurred mainly in cell walls and in crystals dispersed in the root cortex and in the mesophyll. When La was applied, it resulted in increased contents of some essential nutrients (i.e., Ca, P, K, and Mn), while Cu and Fe levels decreased. Moreover, low La concentrations stimulated the photosynthetic rate and total chlorophyll content and lead to a higher incidence of binucleate cells, resulting in a slight increase in roots and shoot biomass. At higher La levels, soybean growth was reduced. This was caused by ultrastructural modifications in the cell wall, thylakoids and chloroplasts, and the appearance of c-metaphases.

Lead tolerance of water hyacinth (Eichhornia crassipes Mart. - Pontederiaceae) as defined by anatomical and physiological traits

This study aimed at verifying the lead tolerance of water hyacinth and at looking at consequent anatomical and physiological modifications. Water hyacinth plants were grown on nutrient solutions with five different lead concentrations: 0.00, 0.50, 1.00, 2.00 and 4.00 mg L-1 by 20 days. Photosynthesis, transpiration, stomatal conductance and the Ci/Ca rate were measured at the end of 15 days of experiment. At the end of the experiment, the anatomical modifications in the roots and leaves, and the activity of antioxidant system enzymes, were evaluated. Photosynthetic and Ci/Ca rates were both increased under all lead treatments. Leaf anatomy did not exhibit any evidence of toxicity effects, but showed modifications of the stomata and in the thickness of the palisade and spongy parenchyma in the presence of lead. Likewise, root anatomy did not exhibit any toxicity effects, but the xylem and phloem exhibited favorable modifications as well as increased apoplastic barriers. All antioxidant system enzymes exhibited increased activity in the leaves, and some modifications in roots, in the presence of lead. It is likely, therefore, that water hyacinth tolerance to lead is related to anatomical and physiological modifications such as increased photosynthesis and enhanced anatomical capacity for CO2 assimilation and water conductance.

Nutrição mineral do mangarito num Latossolo Vermelho Amarelo

The aim of this work was to characterize the nutritional limitations for dry matter production of Xanthosoma mafaffa (L.) Schott. The experiment was carried out in a greenhouse with 0-20 cm samples of a Oxisol under cerrado vegetation, collected at Montes Claros, Minas Gerais State, Brazil. The cultivation was conducted in 3 L pots. The experimental design was totally randomized with 13 treatments and three replications. Treatments were based on the missing element technique (with omission of liming and each one of the macro and micronutrients). The decreasing order of treatments that more influenced the aerial dry matter production was: -liming> -P > -S > test > -B > -liming+Ca+Mg > -N > -K. The omission of Ca, Mg, Zn and Cu did not influence the aerial dry matter production. The decreasing order of treatments that influenced the root dry matter production was: -B > - Mg > -liming+Ca+Mg > -K > -N > -Zn > -liming > -S > -Cu > -Ca > -Cu > -Ca > test > -P.

Nutrição mineral de plantas de maxixe-do-reino

O objetivo desse estudo foi o de caracterizar as limitacoes nutricionais para a producao de materia seca do maxixe-do-reino, Cyclanthera pedata (L.) Schrad. Foram realizados dois cultivos sucessivos, em vasos de 3 dm 3 de solo. O delineamento experimental foi inteiramente casualizado, em treze tratamentos, com tres repeticoes. Os tratamentos foram baseados na tecnica do elemento faltante (em que se omite a calagem e cada um dos macronutrientes e micronutrientes). A producao de materia seca da parte aerea e raiz foi reduzida pela acidez do solo e baixa disponibilidade de macronutrientes, principalmente P, Ca, Mg e S; as plantas foram pouco afetadas pela baixa disponibilidade de micronutrientes.

Selenato e selenito na produção, nutrição mineral e biofortificação com selênio em cultivares de alface¹

O selenio (Se) e um importante elemento ligado a processos fisiologicos na planta, microrganismos, animais e seres humanos. No entanto, para as plantas, seu modo de acao e sua essencialidade sao ainda motivos de controversia. No Brasil, e relevante a falta de informacoes sobre o Se nas culturas agricolas, havendo ainda indicativo de baixa ingestao desse elemento pela populacao. Assim, este estudo objetivou avaliar a influencia da aplicacao de selenato e selenito na biofortificacao com Se e o efeito dessas formas de Se nos teores de macro e micronutrientes em cultivares de alface. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 3 x 2, sendo cinco cultivares de alface (Maravilha de Verao, Rafaela, Great Lakes, Veneranda e Vera), tres concentracoes de Se (0, 10 e 20 μmol L-1) e duas formas de Se (selenato e selenito), com quatro repeticoes. Os resultados encontrados mostram que, para o cultivo de alface em solucao nutritiva, o selenato foi mais indicado para a biofortificacao com Se, enquanto o selenito mostrou ser mais toxico. A aplicacao do selenato resultou em aumento no teor de S na parte aerea, enquanto o selenito reduziu o teor de P, e ambas as formas de Se diminuiram os teores de micronutrientes. Entre as cultivares de alface, nao se observou variacao genotipica para o teor de Se, e pequena variacao foi verificada para producao de materia seca da parte aerea e teores de S, Mg, Mn e Fe.

Produção do maxixe-do-reino em função do sistema de tutoramento e do espaçamento

A field experiment was carried out to evaluate the yield of achocha [Cyclanthera pedata L. Schrad.) ] in Montes Claros, Minas Gerais State, Brazil, as a result of the staking system and within-row spacing. The experimental design was of randomized blocks with four replications, arranged in a scheme 3 x 2, being three staking systems (vertical fence, pole-trellised fence and polyethylene ribbon-trellised fence) and two within-row spacings (1,0 x 1,0 m and 1,0 x 0,5 m), totalizing 24 plots. The fruit number and weight were significantly higher from plants cultivated in the system of vertical fence, where each plant produced 56 fruits on average, corresponding to 2,68 kg. In this system plants presented better fixation to the tutor, besides having minor incidence of damaged fruits caused by the contact with the soil. Highest number, weight of fruits and yield were observed when within-row spacing of 1,0 x 1,0 m was adopted, due to lesser effect of competition between plants for water, nutrients and light. However the yield per area was less due to lower number of plants per ha.