Oscar Mitsuo Yamashita

Effect of environmental factors on germination of Emilia sonchifolia seeds

The knowledge of basic aspects of the biology of weeds can contribute significantly to the development of strategies for their handling. Emilia sonchifolia is a weed spread throughout the Brazilian territory; it presents moderate aggressiveness being found in agricultural and urban areas. This work aimed to evaluate germination of E. sonchifolia seeds in temperature conditions and brightness, stress osmotic, saline and pH of solution. Four experiments were accomplished: a) combination of four temperatures (20 oC, 25 oC, 30 oC and 35 oC) in two conditions of brightness (light absence and presence); b) seven levels of osmotic stress provided for PEG6000 (0; -0.1; -0.2; -0.4; -0.6; -0.8 and -1.0 MPa); c) six levels of saline stress provided for NaCl (0.0; -0.2; -0.4; -0.6; -0.8 and -1.0 MPa) and d) six pH levels (3.0; 5.0; 6.0; 7.0; 9.0 and 11.0) in buffer solutions. The germination of E. sonchifolia seeds was maximized in the presence of light , at constant temperatures of 25 and 30 oC. There was reduction of germination in conditions with osmotic stress starting from -0.1 MPa and of -0.2 MPa for saline stress. E. sonchifolia is sensive to pH variation, with greater germination of seeds occurring only at pH 6.0.

POTENCIAL FISIOLÓGICO DE SEMENTES DE SOJA DESSECADAS COM DIQUAT E PARAQUAT

4 ABSTRACT The type, mode of action and time when the desiccant is applied on soybean, are factors that can affect the physiological quality seeds. But if the operation is performed adequately, it may occur in anticipation of the harvest a few days, getting seeds of higher quality. This work aimed at evaluating the desiccant effect of pre-harvest in the physiological performance of soybean seed. The design was blocks at randomized in a factorial 3 x 4 (desiccants x time) with four replications. The desiccants were Diquat and Paraquat, both in the dose of 400 g.i.a. ha -1 , + control (without desicantion). The times of application were in stages R6.0, R7.1, R7.2 and R7.3. Seeds were subjected to fermenation test, first count of germination, the germination speed rate, accelerated aging, cold testing and electrical conductivity. All tests were carried out at analysis seed laboratory analysis and technology of the University of the State of Mato Grosso. The desiccants were compared by Tukey (p<0.05). In spite of have provided anticipation of crop in only two days in relation to the control, the most favorable time to disecation, so much with Diquat as Paraquat, is at the stage R7.3, and disecateds lots with Paraquat presented better performance in some of the appraised quality tests.

Influência da temperatura e da luz na germinação de sementes de couve-cravinho (Porophyllum ruderale (Jacq.) Cass.)

The knowledge of the biology and of the ecology of weeds precede the elaboration of agronomic strategies for weed control, reducing the costs of the productive process. Certain plants, in addition to other biological characteristics of importance, have their germination capacity influenced by abiotic factors such as temperature and brightness. With the objective of evaluating the germinative response of Porophyllum ruderale seeds, in function of temperature and brightness, two experiments were carried out: in experiment 1, seeds of P. ruderale were put to germinate at three temperatures (20, 25 and 30oC) in two substrates (among and on-paper); in the second experiment, the effect of the light was evaluated in the germination of P. ruderale seeds. The influence of white light, red wavelength, extreme red and light absence were evaluated. Greaterer germination was obtained at temperatures of 25 and 30oC. As the light influenced the germinative process it was verified that seeds of P. ruderale are sensitive to brightness, where the light absence provoked the drastic reduction in the germination of the seeds.

Quality of soybean seeds produced with different doses of molybdenum and cobalt

The present work study assessed the effect of foliar application of different doses of cobalt (Co) and molybdenum (Mo), and seed inoculation with Bradyrhizobium japonicum on the productive characteristics of the soybean crop and the quality of its seeds. The study was carried out in 2005/06, in a Red-Yellow Latosol (Hapludox) dystrophic soil, in the city of Santa Carmen, MT. The experimental design was a randomized block in a 6 X 2 factorial design, with a combination of 12 treatments with four replications for each treatment. The treatments resulted from the combination of six doses of the product Quimifol CoMo Plus (0.0; 0.25; 0.5; 1.0; 1.5; and 2.0 L ha-1), applied foliarly, with and without inoculation of the seeds with a liquid formulation of Bradyrhizobium japonicum, RizoLiq. Based on the results, the following conclusions were drawn: seed inoculation with Bradyrhizobium increased the number of pods per plant and the number of seeds per plant;

Qualidade de sementes de arroz utilizadas no norte de Mato Grosso

The work target was to evaluate the quality of the seeds used by the farmers in five districts (Matupa, Novo Mundo, Nova Guarita, Alta Floresta and Terra Nova do Norte) in the northern area of Mato Grosso state, aiming to characterize their physiologic and physical quality. Forty-five rice seed samples of the Cirad 141 cultivar were collected from producers in the area, in the 2004/05 agricultural season. The seed quality was evaluated by the tests of physical purity, germination and weed seeds. The analysed seeds presented lower physiologic quality than demanded by legislation, concerning the germination, presence of more weed seeds than acceptable, being an important restrictive factor to obtain productive plantations and later on, a high quality product.

Effects of environmental factors induced in the germination of Chaptalia nutans (L.) Polack seeds

Chaptalia nutans is species whose medicinal value has been studied thoroughly, and aspects regarding seed germination are important to define better propagation practices. The objective of the present study was to evaluate the germination response of C. nutans seeds to conditions of light and temperature, as well as osmotic and saline stresses and potassium nitrate. Four experiments were conducted: a) combination of four temperatures (20oC, 25oC, 30oC and laboratory atmosphere) with two light conditions (presence or absence); b) ten levels of osmotic stress induced with manitol (0.0; -0.05; -0.1; -0.2; -0.3; -0.4; -0.5; -0.6; -0.7 and -0.8 MPa); c) eight levels of saline stress induced with NaCl (0.0; -0.1; -0.2; -0.3; -0.4; -0.5; -0.6 and -0.7 MPa) and d) combination of two levels of potassium nitrate (presence or absence) with two temperatures (20 and 25 oC) and two levels of light (presence or absence). Germination of C. nutans seeds was maximized under light, at constant temperatures of 25 , 30 oC, or room temperature between 19 and 31 oC. There was no germination reduction with osmotic stress of up to -0.6 MPa and saline stress of up to -0.5 MPa. The addition of potassium nitrate did not promote any increase in the germination.

Soil quality and its relationship with weeds in urban homegardens of Alta Floresta, Southern Amazonia

Understanding the possible causes of differences in weed composition of homegardens is important to manage such environments and, thus, to control the propagation of weeds. One of the factors that could influence the differences in weed composition of homegardens is soil quality. Soil is a complex and dynamic component subject to change; adequate management is therefore indispensable. The objective of this study was to evaluate the relationship between soil quality and weed species in 30 urban homegardens in Southern Amazonia. We collected samples of the soil seed bank of weeds, calculated quantitative indices of these weed species, and performed an analysis of soil variables (pH, phosphorus, potassium, calcium, magnesium, aluminum, hydrogen, organic matter, sum basis, cation exchange capacity, base saturation, and soil texture). We conducted a principal components analysis to condense the information contained in the soil variables in a small group of new dimensional compositions, a detrended correspondence analysis to investigate the floristic gradients, and a redundancy analysis to model the influence of soil variables on variation in weed spectrum. The soils under the studied urban homegardens showed a chemical quality mostly above the desired minimum of macronutrients, pH, and base saturation. Based on the correlation between the presence of weeds and the physico-chemical quality of the soil, we must recognize that we are still far from obtaining a satisfactory model that can explain the composition of weeds and their relation with soil fertility in urban homegardens.

AVALIAÇÃO SENSORIAL E ACEITAÇÃO COMERCIAL DO COGUMELO COMESTÍVEL PLEUROTUS FLORIDA

O cogumelo comestivel Pleurotus florida , possui caracteristicas sensoriais que atraem consumidores de todo o mundo. A regiao de Alta Floresta apresenta caracteristicas fisiologicas de natureza ideais para o cultivo desse fungo, o que na pratica proporciona emprego para comunidade e oferta comercial do produto com custo inferior ao atual. O objetivo dessa pesquisa foi realizar a avaliacao sensorial do cogumelo comestivel Pleurotus florida e a verificacao da aceitacao comercial do mesmo. O metodo utilizado para levantamento de dados foi aplicacao de questionario utilizando escala hedonica de 9 pontos para avaliacao sensorial do hiratake in natura e cozido, escala de atitude para teste de aceitacao e questao direta para intencao de compra. A tabulacao dos resultados ocorreu com auxilio do software Microsoft Excel. A avaliacao sensorial do hiratake cozido obteve maiores percentuais que na forma in natura . A aceitacao global apontou que 51% dos avaliadores consumiriam o hiratake. Para a avaliacao comercial do P. florida , os resultados apontam que 26% dos julgadores comprariam o hiratake ( P. florida), 46% talvez comprassem e 29% tem duvida se comprariam, revelando boas perspectivas para a producao e comercializacao desse produto.

Initial development of biotopes of Senna occidentalis as a function of acidity and vegetation cover on soil

The objective of this work was to determine the influence of different saturations of basis of soil and vegetation on the initial development of Senna occidentalis, using seeds of different regions of the state of Mato Grosso. Two experiments were carried out. In the first, it was assessed the germination and initial development of the Senna occidentalis weed from cities of Alta Floresta, Juara and Nova Canaa do Norte, sown in soil with four base saturations in soils of (32, 63, 77 and 94 %). The increase in base saturation has improved the development of Senna occidentalis. In the second experiment, it was studied the initial development of Senna occidentalis, based on the presence of straw on the substrate, using a completely randomized design in 2 x 3 x 4 factorial scheme in two locations (Alta Floresta and Juara), three types of mulch (brachiaria grass, rice and maize) and four sowing depths (0, 2, 4, and 8 cm). The rice straw as well as the greater depths, reduced the emergence of seedlings of Senna occidentalis.