Sílvio Júnio Ramos

Impact of selenium supply on Se-methylselenocysteine and glucosinolate accumulation in selenium-biofortified Brassica sprouts

Brassica sprouts are widely marketed as functional foods. Here we examined the effects of Se treatment on the accumulation of anticancer compound Se-methylselenocysteine (SeMSCys) and glucosinolates in Brassica sprouts. Cultivars from the six most extensively consumed Brassica vegetables (broccoli, cauliflower, green cabbage, Chinese cabbage, kale, and Brussels sprouts) were used. We found that Se-biofortified Brassica sprouts all were able to synthesize significant amounts of SeMSCys. Analysis of glucosinolate profiles revealed that each Brassica crop accumulated different types and amounts of glucosinolates. Cauliflower sprouts had high total glucosinolate content. Broccoli sprouts contained high levels of glucoraphanin, a precursor for potent anticancer compound. Although studies have reported an inverse relationship between accumulation of Se and glucosinolates in mature Brassica plants, Se supply generally did not affect glucosinolate accumulation in Brassica sprouts. Thus, Brassica vegetable sprouts can be biofortified with Se for the accumulation of SeMSCys without negative effects on chemopreventive glucosinolate contents.

Interação entre silício e nitrogênio em arroz cultivado sob solução nutritiva

The present study aimed to evaluate the interaction effect between silicon and nitrogen in the content of chlorophyll, nitrate, ammonium and total nitrogen, dry matter production, number of tillers and number of panicles rice-plant cultivated in nutritional solution. A factorial design 5 x 2 trial installed in a completely randomized design was used being two silicon (0 and 50mg L-1) and five nitrogen (20; 50; l00; 200 and 400 mg L-1) concentrations. In the stadium of the flag leaf collar formation SPDA reading and the a and b chlorophyll contents, ammoniacal and total nitrogen determinations in plants were detemined. During the panicle complete maturity stadium, the number of tillers and panicles were evaluated and the aerial part and root dry matter contents and silicon accumulation were determined. The outcomes show that the silicon supply did not change the tillering, the dry matter production and total nitrogen contents. The silicon increased the SPAD values, the a and b chlorophyll and the root nitrate contents, and the number of panicles, especially at high nitrogen levels.The present study aimed to evaluate the interaction effect between silicon and nitrogen in the content of chlorophyll, nitrate, ammonium and total nitrogen, dry matter production, number of tillers and number of panicles rice-plant cultivated in nutritional solution. A factorial design 5 x 2 trial installed in a completely randomized design was used being two silicon (0 and 50mg L-1) and five nitrogen (20; 50; l00; 200 and 400 mg L-1) concentrations. In the stadium of the flag leaf collar formation SPDA reading and the a and b chlorophyll contents, ammoniacal and total nitrogen determinations in plants were detemined. During the panicle complete maturity stadium, the number of tillers and panicles were evaluated and the aerial part and root dry matter contents and silicon accumulation were determined. The outcomes show that the silicon supply did not change the tillering, the dry matter production and total nitrogen contents. The silicon increased the SPAD values, the a and b chlorophyll and the root nitrate contents, and the number of panicles, especially at high nitrogen levels.

Crescimento e teores de boro em plantas de eucalipto (Eucalyptus citriodora) cultivadas em dois latossolos sob influência de doses de boro e disponibilidade de água

3de solo. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 2 x 2, sendo cinco doses de B (0,00; 0,25; 0,75; 2,25; e 6,25 mg kg -1 ); e dois tipos de Latossolo: Latossolo Vermelho-Escuro (LE) e Latossolo Vermelho-Amarelo (LV) e duas tensoes hidricas (-0,033 e -0,010 MPa), com quatro repeticoes. Os resultados indicaram que tanto o LV quanto o LE, nas suas condicoes naturais, nao supriram as exigencias de B em Eucalyptus citriodora. Contudo, os maiores incrementos na producao de materia seca das plantas foram observados em baixas doses de B aplicadas. A umidade do solo e um fator importante no aproveitamento de B do solo pelo Eucalyptus citriodora.

Selenato e selenito na produção e biofortificação agronômica com selênio em arroz

The objective of this work was to evaluate the effect of doses of selenate and selenite on rice (Oryza sativa) biofortification with Se, as well the influence of these forms of Se in the levels of P, S, Fe, and Zn in grains. The experiment was conducted in a greenhouse, in pots with 4 dm3 of a sandy clay loam Latosol, with medium texture, in a 5x2 factorial arrangement with five doses of Se (0, 0.75, 1.50, 3.0, and 6.0 mg dm-3) and two forms of Se (selenate and selenite). Selenate provided greater efficiency of root uptake of Se, plant-use efficiency, translocation from roots to shoots, and content of this element in rice grains. The application of Se during fertilization influences the levels of P, S, and Zn, but does not affect those of Fe in rice grains.

Características fisiológicas de microtomateiros fitocromo-mutantes

Objetivou-se, neste trabalho, caracterizar aspectos fisiologicos de microtomateiros (Lycopersicon esculentum P. Miller cv. Micro-Tom) fitocromo-mutantes. A cultivar Micro-Tom e os mutantes aurea (deficiente na biossintese do cromoforo dos fitocromos), atroviolacea (atv) e high pigment1 (hp1;ambos superexpressam eventos mediados por fitocromos) foram cultivados em condicoes controladas de luz e temperatura e caracterizados no estagio de floracao. O mutante hp1 obteve as maiores taxas de fotossintese potencial e de conteudo de carotenoides. O mutante aurea manteve taxas de fotossintese potencial similares a cultivar Micro-Tom, mesmo expressando o mais baixo conteudo de clorofilas, e tambem expressou o maior conteudo de nitrogenio entre os demais microtomateiros. Os mutantes aurea e hp1 obtiveram os menores conteudos de acucares soluveis totais. O mutante atv expressou o maior conteudo de clorofilas e tambem a menor razao clorofila a/b.

Rendimento de feijão e alterações no pH e na matéria orgânica do solo em função de doses de composto de resíduo de algodão

The objective of this research was to evaluate the yield of bean plants and changes in pH and soil organic matter after compost cotton waste application. An experiment was carried out in an Acrisol. The experimental design was of randomized blocks with five levels of cotton waste compost (0, 20, 40, 60, 80t ha-1) from the textile factory, in five replications. The application of the cotton waste compost promoted increase in the growth and productive characteristics in bean crop, and increased the pH values and soil organic matter. Thus, the compost showed as an alternative for fertilization of the culture.

Silício como amenizador da fitotoxicidade de zinco em plantas jovens de Eucalyptus urophylla cultivadas em solução nutritiva

Zn is an essential micronutrient for the growth and metabolism of plants, but when present in toxic levels in the environment, it can affect the the development of plants. Among the several beneficial effects of silicon (Si), it presents an effect in the decrease or elimination of the adverse effects of heavy metals in the environment. The objective of this work was to evaluate the effect of Si in the alleviation of Zn toxicity on the growth and mineral nutrition of Eucalyptus urophylla seedlings cultivated in nutrient solution. Seedlings of Eucalyptus urophylla were grown in pots containing 3L of Clark nutrient solution, in a 6 x 2 factorial design, using six Zn concentrations (0, 2, 50, 150, 300 and 450 µmol L-1 as ZnSO4 7H2O) and two of Si (0 and 1.78 mmol L-1 of Si as potassium silicate). After eight weeks, plant morphologic traits, dry matter production and content and nutrient utilization were evaluated. The increase of Zn concentrations in the nutrient solution provided higher toxicity in the roots than in the shoots. The addition of the Si alleviated the negative effect of the excess Zn on plant growth, but presented little effect on the nutrient content in these tissues. The silicon addition in the nutrient solution provided a more efficient use of P, Ca, Mg and S for the Eucalyptus urophylla plants.

Anatomic and physiological responses of Panicum aquaticum related to cadmium tolerance

This study evaluated anatomic and physiological modifications in Panicum aquaticum plants related to cadmium (Cd) tolerance. The plants were cultivated in a nutritive solution, with addition of increasing concentration of Cd. The following parameters were analyzed: absorption, translocation, concentration and Cd accumulation, growth, gas exchanges, activity of the antioxidant system, and anatomy of roots and leaves. Absorption and Cd concentration increased throughout the treatments, while accumulation and Cd translocation did not vary, due to maintenance of the biomass. Gas exchanges were not affected by Cd. Specific foliar area increased in the presence of the metal, and might be related to the reduction in leaf blade thickness and chlorophyllic parenchyma. Modifications in stomatal characteristics did not negatively affect gas exchanges. An increase in the exodermis and endodermis thickness restricted Cd translocation to the aerial part, avoiding damages to the photosynthetic system. Activity of the ascorbate peroxidase and catalase in the root contributed to a reduction in the metal toxicity. P. aquaticum presented an efficient capacity for Cd absorption, but restricted translocation. Cd accumulation was higher in the roots. Anatomic and physiological responses show a tolerance of the species to Cd in the evaluated concentrations.