Efeito da profundidade de semeadura e de rodas compactadoras submetidas a cargas verticais na temperatura e no teor de água do solo durante a germinação de sementes de milho

As rodas compactadoras das semadoras-adubadoras têm como principal função, propiciar o bom contato entre o solo e a semente para garantir a germinação das sementes e a emergência das plântulas. Objetivou-se, neste trabalho, estudar a influência de três modelos de rodas compactadoras, três profundidades de semeadura e três níveis de carga sobre a roda compactadora sob a temperatura e o teor de água do solo. O trabalho foi desenvolvido na pista de ensaios de semeadura, localiza em Uberaba, MG, em Latossolo Vermelho distrófico, utilizando-se o delineamento experimental de parcelas sub-subdivididas, com 27 tratamentos e quatro repetições. As rodas com maior área de contato com o solo proporcionaram maiores valores do teor médio de água e da temperatura do solo. O nível de carga sobre a roda compactadora não afetou a temperatura e o teor de água do solo.

Inibidor da ação do etileno na conservação pós-colheita de Chrysanthemum morifolium Ramat cv. Dragon

A durabilidade e a qualidade pós-colheita de flores de corte são atributos fundamentais na sua valoração ao longo da cadeia produtiva e na satisfação dos consumidores. Objetivou-se, nesta pesquisa, verificar o efeito do tiossulfato de prata, associado ou não à sacarose, na manutenção da qualidade pós-colheita de hastes de crisântemos (Chrysanthemum morifolium Ramat cv. Dragon) . O experimento foi conduzido sob delineamento inteiramente casualizado, em esquema fatorial testando soluções de manutenção com tiossulfato de prata (STS), sob cinco níveis (Água destilada; STS a 0,2 mM; STS a 0,2 mM + sacarose a 50 g L-1; STS a 0,4 mM; STS a 0,4 mM + sacarose a 50 g L-1); e data de amostragem, por três níveis (0; 3; 6 dias). Utilizaram-se três repetições com duas hastes florais em cada tratamento. Foram feitas avaliações físicas: coloração, massa fresca e conteúdo relativo de água (CRA); avaliações químicas: açúcares redutores e pigmentos; e avaliações qualitativas: turgescência, cor das flores, e número de botões, flores entreabertas e abertas. O tratamento com 0,2 mM de STS possibilitou melhor manutenção da massa fresca das hastes. A concentração de pigmentos e carboidratos redutores foi maior naqueles tratamentos em que a sacarose foi associada. A coloração e o conteúdo relativo de água foram favorecidos nos tratamentos STS a 0,2 e 0,4mM. A concentração de 0,2 mM de STS foi a que obteve os melhores resultados, prolongando a vida de vaso das hastes. A qualidade das hastes foi superior, tendo as melhores avaliações de conteúdo de água, cor e turgescência.

Biorregulador e pré-condicionamento osmótico na germinação de sementes e no crescimento inicial da muda de carobinha (Jacaranda decurrens subsp. symmetrifoliolata Farias & Proença) - Bignoniaceae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potencial alelopático de Ipomoea fistulosa sobre a germinação de alface e tomate

The objective of the present research was to determine the allelopathic potential of Ipomoea fistulosa plants on germination and growth of seedlings. In laboratory, lettuce and tomato seeds were placed to germinate in the presence of water or Ipomoea fistulosa leaf extract, in the concentrations of 5, 10 e 15% (p/v). In greenhouse, seeds were placed to germinate in trays containing Plantmax (R) substrate and Plantmax (R) substrate + Ipomoea fistulosa dry leaf residue, at 3% (w/w). The aqueous extract inhibited germination, raised the mean germination time of the seeds and reduced the radicle and hypocotyl growth in all used concentrations. In greenhouse, the plant height, leaf number, and dry mass accumulation also were reduced in the presence of the leaf residue in the substrate. The results suggest the presence of allelochemicals in Ipomoea fistulosa and demonstrate the highest sensitivity of lettuce that tomato to these compounds.

Germinação da semente e produção de mudas de cultivares de alface em diferentes substratos

The aim of this paper was to evaluate the effects of the combinations of substrata on germination and development of seedlings of lettuce cultivars. The experiment was carried out in a nursery, in Mato Grosso do Sul State University. There wend compared the following combinations of substrata: washed sand + earthworm humus (2: 1); manure bovine + earthworm humus (2: 1); Plantmax(R) + earthworm humus (2: 1); washed sand + Plantmax(R) (2: 1) and manure bovine + Plantmax(R) (2: 1), and three lettuce cultivars: Crespa sem cabeca, Americana Julia and Baba de Verao. The experimental design was entirely at random, in a 5x3 factorial outline, with four replications and 16 seeds perplot. There were considered for evaluation 10 central seedlings per plot. The characteristics evaluated were: germination percentage (%), index of germination speed (IVE) and dry mass of the whole seedling (g). For all the analyzed variables, the cultivars Baba de Verao and Crespa sem cabeca presented the best results. Manure + humus was the best substratum to obtain seedling with larger development (vigor), althout it did not increase IVE and germination percentage.

Efeito alelopático do extrato aquoso de folhas de girassol sobre a germinação de soja e picão-preto

The aim of this work was to evaluate the allelopathic effect of water extract from sunflower fresh leaves on the germination and initial development of conventional and transgenic soybean cultivars, and of the invasive hairy beggartick (Bidens pilosa L.). Experiments were carried out at Laboratory of Plant Physiology, Universidade Estadual do Oeste do Parana, in 2007. Fresh leaves from sunflower were ground in a blender at the proportion 200g/1L distilled water, resulting in crude extract (100%), in which pH was measured. Dilutions of 80%, 60%, 40% and 20% were done from the crude extract, and only distilled water was used as control. Statistical analysis (Tukey 5% probability) indicated that only the highest extract concentrations (60%, 80% and 100%) influenced the analyzed parameters for conventional and transgenic soybean. Beggartick seeds, however, had germination percentage completely inhibited when 40% water extract was applied, which indicates that sunflower straw could be used as a natural herbicide. Nevertheless, field studies must be carried out to prove such effect.

Germinação e vigor de sementes de Talisia esculenta (St. Hil) Radlk em função de diferentes períodos de fermentação

The present study had the aim of testing the effect of different fermentation periods on the germination and vigour of pitomba seeds. The experiment was carried out in the greenhouse of the Seed Section of the Agrarian Sciences Center of the Federal University of Paraiba, Areia, PB. The fruits were picked directly from maternal trees located in the same municipal district, peeled manually and fermented for 24, 48, 72, 96 and 120 hours, in addition to seeds with pulp (without fermentation). The experiment was entirely randomized with four replications of 25 seeds per treatment. After each fermentation period, the seeds were washed in tap water and left in the laboratory environment for 24 hours on paper towels. Water content, germination and vigor (germination velocity index, seedling length and dry mass., relative frequency and medium time of germination) were measured. Less water content was shown in the seeds fermented for 96 hours (38.5%), while the largest germination percentages were observed after 76 hours of fermentation (93%). In relation to vigour, the best values occurred with 86 and 105 hours of fermentation. Fermentation is recommended for up to 105 hours as appropriate to removal of the pitomba seed aril.

Vermiculita como substrato para o teste de germinação de sementes de barbatimão

The objective of this research was to evaluate the use of vermiculite as a substrate for the germination test of 'barbatimao' seeds and to establish what would be the best granulometry and the best moisture intensity to germinate 'barbatimao' seeds. Four replications of 50 seeds were previously scarified with H(2)SO(4) for 60 minutes. Afterwards, the following germination substrates were evaluated: paper rolls moistened with water equivalent to 2.5 times the weight of the dry paper (control); micron, super thin, thin and average sized vermiculite moistened with 0.5, 1.0, 1.5 and 2.0 times the weight of the dry paper. The germination temperature was 30 C. The percentage of normal seedlings was obtained seven days after sowing (first count) and, then, weekly (up to 28 days). Average time and relative distribution of germination were calculated. It was concluded that the germination of 'barbatimao' seeds can be carried out with either fine vermiculite moistened with water equivalent to 2.0 times the weight of the dry paper or average sized substrate moistened with water equivalent to 0.5 to 2.0 times the weight of dry paper. These treatments resulted in higher and faster germination (21 days), similarly to the paper roll method.

Efeito de biofertilizantes sobre o crescimento micelial e a germinação de esporos de alguns fungos fitopatogênicos

The biofertilizer was produced through anaerobic fermentation of cow manure adding milk, sugar, salts, cow liver parts and bone powder. After 73 days of fermentation it was evaluated the effect on micelial growth of Pythium aphanidermatum, Alternaria solani, Stemphylium solani, Septoria licopersici, Sclerotinia sclerotiorum, Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum f. sp. phaseoli and spores germination of B. cinerea, A. solani, Hemileia vastatrix and Coleosporium plumierae. In relation to micelial growth inhibition, the growth rate was calculated and it was found that, in general, concentrations over 10% caused a total inhibition of growth for the majority of fungi assayed. In case of spores germination, biofertilizer concentration over 20% has inhibited completely the germination of B. cinerea, over 10% inhibited A. solani, 5 and 1% of C. plumierae and H. vastatrix, respectively. Three different biofertilizers were also tested and one of them was less effective, which was the one produced with manure from confined cows opposed to the others produced with grazing cows.

Efeito do bálsamo de copaíba (Copaitéra reticulata ducke) sobre a Germinação de esporos de Fusarium

The germinative capacity of spores of Fusarium was studied in the presence of copahiba balsam (5 to 100%). The culture was carried out in Erlenmeyer flasks with 50ml of ICI medium and 1 ml of the pre-inoculated fungus. In some specific cases, 1 ml of copahiba balsam was added to the medium. The development of spores was significantly reduced in the presence of copahiba balsam. Sensibility to copahiba balsam varied with the different strains of Fusarium.

Efeito alelopático de extratos de parte aérea de barbatimão [Stryphnodendron adstringens (Mart.) Coville] na germinação e desenvolvimento da plântula de pepino

Stryphnodendron adstringens (Mart.) Coville (barbatimão), belonging to Mimosaceae family; it is used as ornamental and the wood is used in civil buildings, edification in wet places, lathe and joinery jobs, being very used also in home-made medicine against hemorrhage, diarrhea, hemorrhoids, conjunctivitis, injury cleaning, uterus hemorrhage, ulcerous hurt and excessive oily skin. The objective of this research was to determine the allelopathic potential of an aqueous extract, boiled or not of S. adstringens (Mart.) Coville, in the Cucumis sativus germination and initial development. Thus, the aqueous vegetable extract was extracted from the shoot, which was triturated in 1L of distilled water to 100g of leaf, being the extract filtrated and separated in boiled and not boiled. The treatments used were distilled water (0%) and boiled and not boiled extracts, in the concentrations of 50 and 100%. The cucumber seeds were put to germinate in Gerbox, having filter paper as substrate, which was wet with 25mL from different treatments, in constant temperature of 25°C. The reading germination was accomplished in breaks of 24 hours, for a period of five consequently days after the beginning of the experiment, considering germinated the seeds that showed 2mm of root, approximately. To dry matter determination, the seedlings with five days after the germination were separated in shoot and root, dried during three days to a constant weight in a 60°C forced draft oven. Through results, it can be concluded that the extract of S. adstringens affected more the Cucumis sativus seedling development than the germination, and it didn't show difference if boiled or not.

Germinação de sementes de pinho-cuiabano sob deficiência hídrica com diferentes agentes osmóticos

The species Schizolobium amazonicum (Huber ex Ducke) commonly known as pinho-cuiabano or paricá, is one of the trees in Amazonian area used for plantings in degraded areas, reforestations and agroforestry systems. The present work evaluated the germinative behaviour of seeds of Schizolobium amazonicum in relation to the hydric stress, defining their levels of tolerance to those limitations in the environment. The seeds were collected from 30 trees in Alta Floresta-MT and submitted the dormancy treatment by submersion into water at 100°C for 1 minute; followed by treatment with fungicide Ridomil and Cercobin 0,25% each, then being left to germinate in a BOD camera at 30°C under a photoperiod of 12 hours. For evaluating the effect of different water potentials in the germinative process, polyethylene glicol (PEG 6000) was used and the salts NaCI and CaCl 2 used to simulate saline stress. The seeds were put to soak in potentials of 0 (control); -0.1 ; -0.2; -0.3; -0.4 and -0.5MPa. For each treatment 5 repetitions of 20 seeds were used in gerbox, placed between filter paper moistened with 20 mL of PEG, NaCI and CaCl 2 solutions. The solutions were changed at intervals of 24 hours for maintenance of the potential. The evaluations of percentages and germination speed were carry out daily for 8 days, being considered germinated the seeds that presented a 2mm root extension or longer. The data were submitted to analysis of variance and averages compared by the Tukey test at 5% probability. It was concluded that osmotic potentials between -0.4 and -0.5MPa inhibited the germination of seeds of Schizolobium amazonicum completely. The osmotic stress caused by CaCl 2, and PEG injured the germination more than did the stress caused by NaCl.

Umedecimento e substratos para germinação de sementes de repolho

The availability of water for seeds is closely related to their germination, since hydration is a limiting factor for their metabolic processes. Therefore, in tests carried out in laboratory, substrate must be sufficiently moistened, in order to assure both the embryo growth and seedling formation. This research was carried out to evaluate the influence of different quantities of water, in different substrates, for cabbage (Brassica oleracea var. capitata) seeds germination. The seeds, processed with Thiran 0.1%, were obtained in shops located in Jaboticabal, São Paulo State, Brazil. Germination tests were made in germitest rolled paper towel substrates, between and on draft paper, moistened with quantities of water equivalent to 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; and 4.0 times the dry substrate weight. For each treatment, four repetitions of 50 seeds were used. The seeds were kept in a germinator, at an alternate temperature of 20-30°C, without further addition of water to the substrate. The evaluations were made on the fifth and tenth days after the experiment preparation. The results obtained revealed that the quantities of water ranging from 1.5 to 2.5 times the paper weight were favorable for seeds germination, mainly in the substrate on and between the paper, while water levels above 3.0 times the substrate weight were harmful for cabbage seeds germination in the rolled paper towel substrates and between the paper.

Sementes de feijão-caupi (Vigna unguiculata L. (Walp), tratadas com extrato de folhas de nim (Azadirachta indica A. Juss.) avaliação da germinação e da incidência de fungos

This study aimed to evaluate the effect of aqueous extract of neem on germination and fungi incidence on seeds of three cultivars (Serrinha, BR 17 and Maranhão) of cowpea. Neem leaves were dryed, crushed and prepared dilutions of 0.5; 1.0; 2.0, 4.0 g dm -3and control. The fungi incidence was evaluated by the test filter paper and germination according to the Rules for Seeds Testing (Regras para Análise de Sementes). In the three cultivars analyzed, reduction in the incidence of Aspergillus sp and Fusarium sp was observed. In relation to the influence of extracts of neem leaves on seed germination, significant effect of extract in Maranhão cultivar was observed, where all concentrations differed from the control, and propovided a considerable increase in the percentage of normal seedlings. It was concluded that the leaf extract of neem was effective in controlling Aspergillus sp, Fusarium sp , Phoma sp and Macrophomina phaseolina at different concentrations in different cultivars and seed germination was stimulated for the Maranhão cultivar.

Superação de dormência e influência dos fatores ambientais na germinação de sementes de Spermacoce latifolia

Understanding basic information on weed biology contributes to the implementation of appropriate management and control strategies. Thus, this work was developed to evaluate the germination of Spermacoce latifolia Aubl. seeds, an important weed in reforestation areas. The seeds were subjected to dormancy break treatments, in which the mechanical scarification, chemical treatment (H2SO 4 and KNO 3), heat treatment, and control, were evaluated. Three more tests were done determinate the effects of temperature (10, 15, 20, 25, 30 and 35°C), light filters (absence of light and red, green, yellow, distant red, blue, orange and clear light) and water availability (0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa) on the seeds germination and vigor. The treatments were arranged in a completely randomized design with four replications, and the experimental plot was constituted by gerbox plastic boxes with 50 seeds. The mechanical scarification (sanding) provided the best dormancy break, indicating that Spermacoce latifolia seeds have tegument water impermeability. The seeds showed higher germination percentage under conditions of mild water stress (-0.2 MPa) and the optimal temperature was 25°C. The blue light reduced seed germination.