Humberto Pereira da Silva

Tolerância de mamoneira ao herbicida pendimethalin em solos com diferentes capacidades de adsorção

The castor bean is a species of slow initial growth. The absence of registered herbicides for this crop is still a limiting factor for its expansion. The aim of this study was to evaluate the castor bean tolerance to the herbicide pendimethalin in soils with different adsorption capacities. The experiment was conducted under greenhouse conditions in a completely randomized design with five replications and consisted of a factorial combination of eight doses of the herbicide pendimethalin applied as pre-emergence (0; 187,5; 375; 750; 1500; 3000; 6000 and 12000 g ha-1 i.a.), and four types of substrate (clay loam, sandy clay loam, sandy loam and sandy soil). At 22 days after sowing the variables: plant height, leaf area, fresh and dry mass of shoots, root system volume and dry weight were determined. It was concluded that the dose of the herbicide pendimethalin tolerated by the castor bean is influenced by the adsorption capacity of the soil. The herbicide was found to be very selective to this crop, not causing significant reduction of plant growth at the doses indicated to be used for weed control.

Qualidade de sementes de Helianthus annuus L. em função da adubação fosfatada e da localização na inflorescência

In recent years, the expansion of sunflower promoted a search for genetic material more competitive, and for seeds with a maximum physical, physiological and health quality. In the field, harvesting time and plant nutrition are essential in the expression of these qualities. With this objective, this research aimed to evaluate the physical and physiological quality of sunflower seeds under different phosphorus levels and locations within the same inflorescence. The experimental design was randomized blocks in factorial (3x2), being the first factor, the location of the seed in the inflorescence (outside, middle and center) and the second phosphorus levels (zero and to 70kg ha-1 super-simple). Its application was performed during the culture deployment . Seeds were subjected to the moisture content determination, thousand seed weight, seed weight per inflorescence location in germination and vigor (first count and index of germination rate). Phosphorus fertilization allowed an increase in physical and physiological quality of sunflower seeds. The region along the periphery with the environment contributes in most to obtain a better physical and physiological quality of sunflower seeds. The physical quality is affected by the location of seeds in inflorescences, which are heavier in the periphery, followed by middle and having the center with lighter seeds.

Physiological quality of osmoprimed gherkin seeds

It was aimed to verify the effect of different methodologies of osmopriming on physiological quality of gherkin seeds. Prior, it has been characterized the initial profile of the gherkin seeds. Then, the seeds were osmoprimed in gerboxes containing two blotter papers wetted with osmotic solutions in a volume equal to three times the paper dry weight and kept in BOD at 15 °C. After the priming, the seeds were dried at room temperature for 48 hours. Then, the following variables were evaluated: seeds moisture content, percentage of germination, percentage of emergence, emergence speed index and electrical conductivity. The analyses of variances were realized according to a randomized design in a factorial scheme 3 x 2 x 4: three solutes (polyetilene glycol 6000 - PEG, potassium nitrate - KNO3 and PEG + KNO3), two osmotic potentials (-0.55 and -1.10 MPa) and four times of priming (24, 48, 72 and 96 hours), followed by analyses of regression. It is concluded that the priming has no effect on germination and affects positively the vigor of the gherkin seeds lots; osmopriming with potassium nitrate is effective in improving the physiological quality of gherkin seeds lot.

Atributos físicos do solo, adubado com lodo de esgoto e silicato de cálcio e magnésio

Este trabalho teve como objetivo avaliar o efeito da aplicacao de lodo de esgoto e de silicato de calcio e magnesio sobre os atributos fisicos de um Cambissolo Haplico, cultivado com girassol. Os tratamentos foram distribuidos em esquema fatorial (4 x 2) + 1, correspondendo a quatro doses de lodo de esgoto desidratado (0; 6,25; 12,5 e 18,5 t ha-1), duas doses de silicato de calcio e magnesio (0 e 240 g m-1) e um tratamento adicional com adubacao mineral. O delineamento utilizado foi em blocos casualizados, com tres repeticoes. Apos 150 dias da adubacao, coletaram-se amostras de solos, nas camadas de 0-20 e 20-40 cm, para avaliacao da densidade aparente, densidade de particula, porosidade total, grau de dispersao, grau de floculacao, indice de estabilidade de agregados, diâmetro medio ponderado, diâmetro medio geometrico e resistencia do solo a penetracao. O tratamento adicional, correspondente a adubacao mineral, nao diferiu dos tratamentos correspondentes as adubacoes com lodo de esgoto e silicato de calcio e magnesio, em relacao aos atributos fisicos do solo. Para o silicato de calcio e magnesio, tambem nao se constataram diferencas nos atributos fisicos do solo, entre a dose zero e 240 g m-1. Por outro lado, a aplicacao de lodo de esgoto diminuiu o grau de dispersao de argila e aumentou a porosidade total do solo, o grau de floculacao de argilas e o indice de estabilidade de agregados a umido, nao tendo, porem, influenciado os demais atributos fisicos.

Effect of the thidiazuron in vitro micropropagation of two castor bean genotypes by organogenesis.

The objective of this research was to evaluate the effectiveness to induce the multiplication of shoots in the BRS Nordestina and CSRN 142 castor bean genotypes, in the explant apical meristem, determining the best treatment with the thidiazuron (TDZ) growth regulator and to indicate the satisfactory concentration of the indoleacetic acid (AIA) for the ex vitro rooting. The Murashige and Skoog medium, was used supplemented with TDZ in the concentrations 0 (control); 0.5, 1.0, 2.0, 5.0 e 10.0 mg L-1, with three explants per flask, in randomized blocks. The evaluations were made after 45 days of cultivation, being analyzed the number of brunches for explant and the percentage of necrosis. In the ex vitro rooting, the use of AIA was made, in the concentrations 0, 0.125, 0.25, 0.5 and 1.0 g L-1 in the acclimatization substrate. It was observed that the concentration of 0.5 mg L-1 of TDZ provided the best results in vitro proliferation, reaching 16.9 brunch for explant. In the ex vitro rooting, the most promising treatment was substrate + 0.125 g L-1 of AIA, with 75% of rooted plants. It was verified that the TDZ induces the over brunching in the two genotypes and that the ex vitro rooting is a viable alternative for the programs of plants improvement.

Tolerância da mamoneira ao herbicida trifluralin em solos com diferentes texturas

The scarcity of registered herbicides for cultivation of castor beans is still a limiting factor for its expansion. Thus, the aim of this study was to evaluate the tolerance of castor bean to trifluralin herbicide in soils of different textures. The experiment was conducted in a greenhouse in a completely randomized design with five replications in a factorial with 8 doses of the trifluralin herbicide (0; 187.5; 375; 750; 1.500; 3.000; 6.000 and 12.000 g ha-1 i.a.) applied at pre-emergence and four types of substrates (washed sand; sandy loam; sandy clay loam; and clay loam soil). At 28 days after sowing, the variables plant height, leaf area, shoot dry weight, volume and dry mass of roots were measured. It was concluded that the tolerance of castor bean to trifluralin herbicide is influenced by chemical and physical characteristics of soil. In sandy and sandy loam soils, doses of trifluralin below those commonly used for weed control are sufficient to cause the decrease in the growth of castor bean plants.

Initial growth of Acacia mangium Willd in soil conditioner formed of coconut fiber and aggregating residue.

The purpose of this work was to evaluate litter layer (soil conditioner) formed of coconut fiber and aggregating residue with different substrate in the initial growth of Acacia mangium Willd plants. A completely randomized block was utilized, with 13 treatments and three replications, in a factorial arrangement (6 x 2 + 1), with 6 proportions of fiber of coconut and aggregating residue (100 and 0%, 90 and 10%, 80 and 20%, 70 and 30%, 60 and 40%, 50 and 50%), 2 substrates, one containing sewage sludge (subsoil of Red-Yellow Latosol (LVA) plus sewage sludge in the proportion 2:1) and the other with bovine manure (subsoil of Red-Yellow Latosol (LVA) plus decomposed bovine manure in the relation 3:1), and the control as additional treatment, subsoil of Red-Yellow Latosol (LVA). After 173 days of the sowing, the litter layer containing subsoil of LVA and bovine manure was found to be superior to the substrate with subsoil of LVA and sewage sludge in the initial development of A. mangium Willd in height and length of the root. Conditioners containing 90 to 100% of coconut fiber and of 0 to 10% of aggregating residue provided better characteristics of growth of A. mangium Willd in field conditions.

DETERMINAÇÃO DE INIBIDORES E SUPERAÇÃO DE DORMÊNCIA EM SEMENTES DE CUTIEIRA

The objective of this work was to verify the presence of inhibitors of germination and vigor in different parts of the seed of Cutieira. Secondly, we evaluate the effects of the methods for breaking dormancy, as well as to identify and quantify the microflora in Cutieira seeds. In the preliminary phase of the research, using lettuce seeds as an indicator of inhibitors and aqueous extract of seed coat, film, tissue reserves, cotyledon and embryo axis of Cutieira seeds. It was evidenced the presence of inhibitors primarily in tissues of the embryonic axis and cotyledons. In a second stage of the research, in finding overcomes Cutieira seed dormancy, fruits of Cutieira were collected and separated into freshly harvested fruits and remnants. The experimental design was completely randomized, factorial 2 x 5, with two types of seed from freshly harvested fruits and remnants and five pre-germination treatments. The seed coat removal promotes increased germination and seed vigor derived from harvested fruits. Fungi identified in the cutieira seeds were Aspergillus niger, Aspergillus flavus, Penicillium sp. and Rhizopus sp.