Avaliação do sistema de monitoramento computadorizado de digestão in vitro: 1. Testes preliminares

O objetivo deste trabalho foi testar o sistema de monitoramento computadorizado da produção de gás in vitro. Essa técnica facilita estudos da degradação das frações solúveis e insolúveis das forragens, quantificadas pela produção de gás (CO2 e CH4) oriunda do metabolismo microbiano e medida por sensor de pressão. Diversas quantidades de amostras (50 a 110 mg de feno de alfafa) e outros alimentos foram testadas. Também, a influência da quantidade de líquido ruminal (2,0 ou 3,0 mL), com ou sem barras magnéticas agitadoras nos frascos incubatórios, na digestibilidade de 100 mg de feno de alfafa, foi estudada. A quantidade de 100 mg de amostra, 2,0 mL de líquido ruminal e sem barra magnética agitadora, proporcionou os menores coeficientes de variação na produção de gás. em conclusão, 2,0 mL de líquido ruminal, sem barra e com 100 mg de amostra, apresentaram maior precisão na curva de digestão.

Histologia da pele da carpa prateada (Hypophtalmichthys molitrix) e testes de resistência do couro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação do comportamento sexual em touros Nelore: comparação entre os testes da libido em curral e do comportamento sexual a campo

Objetivou-se determinar a eficiência do teste da libido realizado em curral em comparação ao teste realizado a campo e relacioná-los à taxa de gestação em estação de monta de 120 dias. Treze touros aptos à reprodução foram submetidos ao teste da libido em curral por 3 horas. Desses touros, nove foram submetidos à avaliação a campo na proporção touro:vaca de 1:33. A cada 21 dias, foi diagnosticada a gestação por meio de avaliações ultra-sonográficas. No teste em curral, observou-se que, quanto maior o tempo, maiores foram os escores de classificação e que nenhum touro efetuou serviço completo nos 10 minutos iniciais do teste. Com um touro classificado como muito bom obteve-se 84,80% de prenhez, porém touros questionáveis proporcionaram taxas de prenhez de 86,67 e 96,55% ao final da estação. As correlações entre características físicas e morfológicas do sêmen mantiveram-se próximas de zero ou foram nulas. Os principais sinais fisiológicos do comportamento sexual foram o ato de cheirar ou lamber o corpo da fêmea, cheirar ou lamber a vulva, seguidos ou não por reflexo de Flehmen. em animais da raça Nelore, o tempo de 30 minutos de observação mostrou-se mais eficiente para a realização do teste da libido em curral. O teste da libido realizado a campo no período diurno não foi eficaz em predizer a libido de todos os animais estudados, em decorrência, provavelmente, do comportamento sexual noturno de alguns reprodutores.

Relação da taxa de gestação com sêmen bovino congelado e testes de avaliação espermática in vitro

Avaliou-se a relação entre os testes complementares (teste hiposmótico, teste de termorresistência lento e teste de reação acrossômica) e os testes de avaliações convencionais (aspectos físicos e morfológicos) de sêmen bovino congelado/descongelado e os índices de prenhez. Os valores médios da motilidade espermática progressiva retilínea avaliados pelo teste de termorresistência foram de 53,48 (pós-descongelamento), 43,69 (60 minutos), 35,88 (120 minutos) e 33,04% (180 minutos) e a porcentagem de células reativas ao teste hiposmótico foi de 37,89%. Correlação positiva e de média intensidade foi encontrada para a motilidade espermática progressiva retilínea pós-descongelamento e o teste hiposmótico (0,21). Entretanto, a correlação da motilidade aos 180 minutos com o teste hiposmótico foi alta (0,64). A porcentagem de células que tiveram acrossoma reagido pós-descongelamento foi de 9,85%, apresentando correlações negativas de média e alta intensidade (-0,25 e -0,46, respectivamente) com a motilidade espermática progressiva retilínea pós-descongelamento e após 3 horas de incubação. Não houve correlação dos testes complementares e da motilidade pós-descongelamento com a taxa de gestação. Nenhum parâmetro considerado isoladamente serviu para avaliar a capacidade fertilizante do sêmen congelado/descongelado.

Effect of the type of environmental stress on the emergence of sunflower (Helianthus annus L.), soybean (Glycine max (L.) Merril) and maize (Zea mays L.) seeds with different levels of vigor

Sowing is a critical time in the cycle of a crop and the seeds are frequently exposed to adverse conditions that may compromise the establishment of seedlings in the field. on this basis, the objective of the present study was to determine the effect of types of environmental stress on the emergence of sunflower, maize and soybean seeds with different levels of vigor. High vigor seeds were artificially aged in order to obtain medium and low vigor seeds and then they were sown in clay soil in plastic boxes and submitted to the following types of environmental stress during the germination process : 1) high temperature (35degreesC), 2) low temperature (15 or 18degreesC), 3) water excess (Psi > -0.0001 MPa), 4) water deficiency (Psi approximately equal to -1.1; -1.2 and -0.6 MPa for sunflower, maize and soybean, respectively), 5) sowing at a depth of 7 cm and 6) pathogenic infection of sunflower seeds with Alternaria helianthi, of maize seeds with Fusarium moniliforme and of soybean seeds with Colletotrichum dematium, var. truncata. The results were compared to those obtained with controls sown under optimal condition. It was concluded that: 1) the effect of seed vigor on emergence depends on the type of enviromental stress to which the seeds are exposed, 2) the stress to which the the seeds demonstrated highest sensitivity varied with species and 3) high temperature stress was the one that most impaired the emergence of the three species.

Efeito da altura e da frequência de corte sobre a produção, composição bromatológica e vigor de rebrota do capim-colonião

O trabalho foi conduzido no Campus da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal/UNESP com o objetivo de estudar o efeito de duas frequências (35 e 42 dias) e duas alturas do corte (15 cm e 30 cm do solo) sobre as características morfo-fisiológicas de recuperação, a produção e a composição bromatológica do capim-colonião (Panicum maximum Jacq.). Os resultados revelaram que plantas cortadas a intervalos de 42 dias apresentaram maior percentagem de perfilhos decapitados (53,70%), menor vigor de rebrota (918,89 kg de MS/ha/21 dias), porém maior produção de matéria seca (12.652,67 kg/ha). O vigor de rebrota mostrou melhor correlação com a percentagem de perfilhos decapitados (r = -0,60*), do que com os teores de carboidratos totais não estruturais da base do colmo (r = -0,04) e da parte subterrânea (r = -0,39). Com base nas produções de matéria seca e de proteína bruta, bem como, na composição bromatológica, o capim-colonião poderia ser cortado, no período de janeiro a abril, a intervalos de 42 dias, independentemente das alturas adotadas (15 cm ou 30 cm de solo).

Melanocytes in the testes of Eupemphix nattereri (Anura, Leiuperidae): Histological, stereological, and ultrastructural aspects

Ectothermic vertebrates have a well-developed system of melanin-containing cells, which localize in several organs and tissues and compose an extracutaneous pigmentary system. This research aimed at characterizing histological and ultrastructural patterns of pigmented cells in the testes of the anura Eupemphix nattereri (Steindachner, 1963), including the stereological and quantitative evaluation of this cell type in the gonads. Ten adult males were collected in Nova Itapirema, São Paulo, Brazil, and submitted to morphological studies with light and transmission electron microscopy. The testis presents a great number of large cells with many brown granules and long cytoplasmic processes. The pigmented cells found in the testis are structurally similar to melanocytes, characterized by large amounts of melanosomes. The cells may be in intimate contact with the same cell type, with myoid cells surrounded by a large amount of collagen fibers, Leydig cells, and next to fibroblasts. The distribution and amount of extracutaneous melanocytes is variable when other organs and membranes are analyzed, allowing the establishment of species-specific patterns for the extracutaneous pigmentary system.

EFFECT OF DROUGHT AND DEFOLIATION STRESS IN THE FIELD ON SOYBEAN SEED-GERMINATION AND VIGOR

Although drought and defoliation stress have been shown to reduce soybean [Glycine max (L.). Merr.] yield, little information has been published regarding their effects on soybean seed quality. Field experiments were conducted in 1986, 1987, and 1989 to evaluate the effect of drought and defoliation (1989 only) stress during soybean seed development on seed germination and vigor. Essex (MG [maturity group] V) and Union (MG III) were grown in 1986 and 1987, and Harper (MG III) and McCall (MG 00) in 1989. Moisture treatments were either well watered or drought stressed during seed development (R5 to R7). In 1989, a total defoliation treatment was also imposed at R6 as an additional stress factor. There were significant reductions in yield and yield components following drought stress in all 3 yr and following defoliation in 1989. Leaf conductance and transpiration also decreased in the drought stress treatments. There was no effect of drought stress on seed germination or seed vigor as measured by accelerated aging germination and the cold test across the four cultivars (determinate and indeterminate) and 3 yr. In 1989 slight changes in 3-d germination and conductivity occurred for some drought stress treatments. Most of this response, however, was related to increased occurrence of hard seed, which does not represent an indication of a change in vigor. Seed germination and vigor were significantly reduced for small, flat, shriveled, and underdeveloped seeds that only occurred following defoliation. These seeds represented a small portion of the seed lot that would normally be removed during conditioning. The data suggest that drought stress would have no effect on seed germination or vigor, unless the stress was severe enough to produce shriveled, flat, underdeveloped seeds.

Histology and morphometry of the testes of adult domestic cats (Felis catus)

Testicles of 30 mongrel cats were analyzed histologically and morphometrically, divided into three groups: G1 (1-2 years old), G2 (over 2 and up to 4 years old) and G3 (over 4 and up to 6 years old). After orchiectomy and histopathology, the morphometric parameters studied were: thickness of the tunica albuginea (72 mu m) and seminiferous epithelium (77.19 mu m), perimeter (53.81; 90.57 mu m), (54.80; 101.07 mu m); area (174.23; 494.55 mu m(2)), (176.68; 629.70 mu m(2)); maximum diameter (14.94; 28.02 mu m), (14.76; 31.66 mu m); minimum diameter (13.25; 21.92 mu m), (13.30; 24.52 mu m); and shape factor (index for regularity of the format) (1.36; 1.36), (1.39; 1.35) of the nucleus and cytoplasm of spermatogonia and Leydig cells, respectively. The results can be used for comparative studies and contribute knowledge concerning the height of the seminiferous epithelium, thickness of the tunica albuginea and size of spermatogonia and Leydig cells.

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.

Comportamento de cultivares de soja quanto a qualidade fisiológica de sementes

This work was carried out in order to evaluate if there was a relationship between genotypes and the physiological soybean (Glycine max L.) seed quality. It was conducted during three years using seven cultivars each year. The seeds were harvested at: 1) yellow radicle or expanded pod stage, 2) yellow pod or physiological maturity (R7), 3) harvest maturity (R8), and 4) R8 + 21 days delay. Seed moisture content, standard germination, and vigor tests were performed. The germination and vigor evaluated by accelerated aging and electrical conductivity did not show physiological seed quality differences among genotypes as harvested at physiological maturity. Then, the evaluation of seed germination and vigor, when the environment is not a considered factor, is not an efficient method to show differences among soybean genotypes in terms of seed quality.

Correlation of electrical conductivity and other vigor tests with field emergence of soybean seedlings

Seeds from six soybean cultivars (Cristalina, IAC 31-Foscarin, IAC-15, UFV-10, IAC-14 and IAS-5) and from five soybean cultivars (IAC 31-Foscarin, IAC-15, IAC-14, IAS-5 and Iguacu) were evaluated in 1993 and 1994, respectively, in terms of physiological seed quality by the mechanical damage (MD), standard germination (SG), accelerated aging (AA), electrical conductivity (EC), and seedling field emergence (FE) tests. Significant correlations were detected between SG, AA and EC and FE. However, in terms of the cultivar or the year, the degree of association among these parameters can change based on the environmental conditions of each year.

Phytochrome and light influence on germination and vigor of ocimum gratissimum L. (Lamiaceae) seeds under high irradiance conditions

Ocimum gratissimum seed germination (% germination and vigor) has been found as phytochrome dependent, having a typical High Irradiant Response (HIR). Seven treatments were tested: daylight (DL), red (R), far-red (FR), blue (B), green (G), dark (DK), and reversible (RVB). No statistical difference among the DL, R, FR, B, and G were found. DK and RVB were statistically equal and presented the lowest results. The germination also occurred in the DK treatment but in non-useful rates, and it was nonreversible in the RVB treatment. It allows these seeds to be classified as positively photoblastic. The minimum energy need to initiate the germination was evaluated by a fluency-response curve. It plotted four different exposition times to R light (1 second, 60 seconds, 1 hour, and 13 hours) against percent germination. Useful germination occurred only after 1 hour, confirming the high energy needed to incite the process. The germination rate increased with the raise of the photoequilibrium (j). The high positive correlation index found confirms the phytochrome influence in this process. Facing all the results presented here, it is suggested to sow these seeds under direct and highly intense sunlight. It is preferable to avoid places exposed to variations in the shading, because inhibition induced by dense shade effects (low R/FR ration and consequently low j established) were demonstrated irreversible, and it can lead to undesirable loss of the germination power.