998 resultados para Color-magnitude Relation
Resumo:
The effect of carotenoid pigments on the egg yolk color was studied in this paper. Three types of maize of known genetical constitution were used: Cateto, with deep orange endosperm; Armour, with yellow-orange endosperm and Cristal, with white endosperm. The carotenoid pigments of the two colored maizes were analysed: the total and both the active parts in relation to vitamin A and the zeaxanthin part showed to be practically double in the deep orange corn. The color of the yolk was orange when the ration had the deep orange corn and yellow in the case of the yellow-orange corn. The increase in shade was proportional to the amount of pigment present in the grains. If green feeds is added to the ration with white corn, the yolk becomes yellow or orange, depending on the amount of green given to the chickens. The practical importance of controlling the color of the yolk was emphasized.
Resumo:
This paper deals with problems on population genetics in Hymenoptera and particularly in social Apidae. 1) The studies on populations of Hymenoptera were made according to the two basic types of reproduction: endogamy and panmixia. The populations of social Apinae have a mixed method of reproduction with higher percentage of panmixia and a lower of endogamy. This is shown by the following a) males can enter any hive in swarming time; b) males of Meliponini are expelled from hives which does not need them, and thus, are forced to look for some other place; c) Meliponini males were seen powdering themselves with pollen, thus becoming more acceptable in any other hive. The panmixia is not complete owing to the fact that the density of the breeding population as very low, even in the more frequent species as low as about 2 females and 160 males per reproductive area. We adopted as selection values (or survival indices) the expressions according to Brieger (1948,1950) which may be summarised as follows; a population: p2AA + ²pq Aa + q2aa became after selection: x p2AA + 2pq Aa + z q²aa. For alge-braics facilities Brieger divided the three selective values by y giving thus: x/y p2 AA + y/y 2 pq Aa + z/y q²aa. He called x/y of RA and z/y of Ra, that are survival or selective index, calculated in relation to the heterozygote. In our case all index were calculated in relation to the heterozygote, including the ones for haploid males; thus we have: RA surveval index of genotype AA Ra surveval index of genotype aa R'A surveval index of genotype A R'a surveval index of genotype a 1 surveval index of genotype Aa The index R'A ande R'a were equalized to RA and Ra, respectively, for facilities in the conclusions. 2) Panmitic populations of Hymenoptera, barring mutations, migrations and selection, should follow the Hardy-Weinberg law, thus all gens will be present in the population in the inicial frequency (see Graphifc 1). 3) Heterotic genes: If mutation for heterotic gene ( 1 > RA > Ra) occurs, an equilibrium will be reached in a population when: P = R A + Ra - 2R²a _____________ (9) 2(R A + Ra - R²A - R²a q = R A + Ra - 2R²A _____________ (10) 2(R A + Ra - R²A - R²a A heterotic gene in an hymenopteran population may be maintained without the aid of new mutation only if the survival index of the most viable mutant (RA) does not exced the limiting value given by the formula: R A = 1 + √1+Ra _________ 4 If RA has a value higher thah the one permitted by the formula, then only the more viable gene will remain present in the population (see Graphic 10). The only direct proof for heterotic genes in Hymenoptera was given by Mackensen and Roberts, who obtained offspring from Apis mellefera L. queens fertilized by their own sons. Such inbreeding resulted in a rapid loss of vigor the colony; inbred lines intercrossed gave a high hybrid vigor. Other fats correlated with the "heterosis" problem are; a) In a colony M. quadrifasciata Lep., which suffered severely from heat, the percentage of deths omong males was greater .than among females; b) Casteel and Phillips had shown that in their samples (Apis melifera L). the males had 7 times more abnormalities tian the workers (see Quadros IV to VIII); c) just after emerging the males have great variation, but the older ones show a variation equal to that of workers; d) The tongue lenght of males of Apis mellifera L., of Bombus rubicundus Smith (Quadro X), of Melipona marginata Lep. (Quadro XI), and of Melipona quadrifasciata Lep. Quadro IX, show greater variationthan that of workers of the respective species. If such variation were only caused by subviables genes a rapid increasse of homozigoty for the most viable alleles should be expected; then, these .wild populations, supposed to be in equilibrium, could .not show such variability among males. Thus we conclude that heterotic genes have a grat importance in these cases. 4) By means of mathematical models, we came to the conclusion tht isolating genes (Ra ^ Ra > 1), even in the case of mutations with more adaptability, have only the opor-tunity of survival when the population number is very low (thus the frequency of the gene in the breeding population will be large just after its appearence). A pair of such alleles can only remain present in a population when in border regions of two races or subspecies. For more details see Graphics 5 to 8. 5) Sex-limited genes affecting only females, are of great importance toHymenoptera, being subject to the same limits and formulas as diploid panmitic populations (see formulas 12 and 13). The following examples of these genes were given: a) caste-determining genes in the genus Melipona; b) genes permiting an easy response of females to differences in feeding in almost all social Hymenoptera; c) two genes, found in wild populations, one in Trigona (Plebéia) mosquito F. SMITH (quadro XII) and other in Melipona marginata marginata LEP. (Quadro XIII, colonies 76 and 56) showing sex-limited effects. Sex-limited genes affecting only males do not contribute to the plasticity or genie reserve in hymenopteran populations (see formula 14). 6) The factor time (life span) in Hymenoptera has a particular importance for heterotic genes. Supposing one year to be the time unit and a pair of heterotic genes with respective survival indice equal to RA = 0, 90 and Ra = 0,70 to be present; then if the life time of a population is either one or two years, only the more viable gene will remain present (see formula 11). If the species has a life time of three years, then both alleles will be maintained. Thus we conclude that in specis with long lif-time, the heterotic genes have more importance, and should be found more easily. 7) The colonies of social Hymenoptera behave as units in competition, thus in the studies of populations one must determine the survival index, of these units which may be subdivided in indice for egg-laying, for adaptive value of the queen, for working capacity of workers, etc. 8) A study of endogamic hymenopteran populations, reproduced by sister x brother mating (fig. 2), lead us to the following conclusions: a) without selection, a population, heterozygous for one pair of alleles, will consist after some generations (theoretically after an infinite number of generation) of females AA fecundated with males A and females aa fecundated with males a (see Quadro I). b) Even in endogamic population there is the theoretical possibility of the presence of heterotic genes, at equilibrium without the aid of new mutations (see Graphics 11 and 12), but the following! conditions must be satisfied: I - surveval index of both homozygotes (RA e Ra) should be below 0,75 (see Graphic 13); II - The most viable allele must riot exced the less viable one by more than is permited by the following formula (Pimentel Gomes 1950) (see Gra-fic 14) : 4 R5A + 8 Ra R4A - 4 Ra R³A (Ra - 1) R²A - - R²a (4 R²a + 4 Ra - 1) R A + 2 R³a < o Considering these two conditions, the existance of heterotic genes in endogamic populations of Hymenoptera \>ecames very improbable though not - impossible. 9) Genie mutation offects more hymenopteran than diploid populations. Thus we have for lethal genes in diploid populations: u = q2, and in Hymenoptera: u = s, being u the mutation ratio and s the frequency of the mutant in the male population. 10) Three factors, important to competition among species of Meliponini were analysed: flying capacity of workers, food gathering capacity of workers, egg-laying of the queen. In this connection we refer to the variability of the tongue lenght observed in colonies from several localites, to the method of transporting the pollen in the stomach, from some pots (Melliponi-ni storage alveolus) to others (e. g. in cases of pillage), and to the observation that the species with the most populous hives are almost always the most frequent ones also. 11) Several defensive ways used for Meliponini to avoid predation are cited, but special references are made upon the camouflage of both hive (fig. 5) and hive entrance (fig. 4) and on the mimetism (see list in page ). Also under the same heading we described the method of Lestrimelitta for pillage. 12) As mechanisms important for promoting genetic plasticity of hymenopteran species we cited: a) cytological variations and b) genie reserve. As to the former, duplications and numerical variations of chromosomes were studied. Diprion simile ATC was cited as example for polyploidy. Apis mellife-ra L. (n = 16) also sugests polyploid origen since: a) The genus Melipona, which belongs to a" related tribe, presents in all species so far studied n = 9 chromosomes and b) there occurs formation of dyads in the firt spermatocyte division. It is su-gested that the origin of the sex-chromosome of Apis mellifera It. may be related to the possible origin of diplo-tetraploidy in this species. With regards to the genie reserve, several possible types of mutants were discussed. They were classified according to their survival indices; the heterotic and neutral mutants must be considered as more important for the genie reserve. 13) The mean radius from a mother to a daghter colony was estimated as 100 meters. Since the Meliponini hives swarm only once a year we may take 100 meters a year as the average dispersion of female Meliponini in ocordance to data obtained from Trigona (tetragonisca) jaty F. SMITH and Melipona marginata LEP., while other species may give different values. For males the flying distance was roughly estimated to be 10 times that for females. A review of the bibliography on Meliponini swarm was made (pg. 43 to 47) and new facts added. The population desity (breeding population) corresponds in may species of Meliponini to one male and one female per 10.000 square meters. Apparently the males are more frequent than the females, because there are sometimes many thousands, of males in a swarm; but for the genie frequency the individuals which have descendants are the ones computed. In the case of Apini and Meliponini, only one queen per hive and the males represented by. the spermatozoos in its spermateca are computed. In Meliponini only one male mate with the queen, while queens of Apis mellijera L. are fecundated by an average of about 1, 5 males. (Roberts, 1944). From the date cited, one clearly sees that, on the whole, populations of wild social bees (Meliponini) are so small that the Sewall Wright effect may become of great importance. In fact applying the Wright's formula: f = ( 1/aN♂ + 1/aN♀) (1 - 1/aN♂ + 1/aN♀) which measures the fixation and loss of genes per generation, we see that the fixation or loss of genes is of about 7% in the more frequent species, and rarer species about 11%. The variation in size, tergite color, background color, etc, of Melipona marginata Lep. is atributed to this genetic drift. A detail, important to the survival of Meliponini species, is the Constance of their breeding population. This Constance is due to the social organization, i. e., to the care given to the reproductive individuals (the queen with its sperm pack), to the way of swarming, to the food storage intended to control variations of feeding supply, etc. 14) Some species of the Meliponini are adapted to various ecological conditions and inhabit large geographical areas (e. g. T. (Tetragonisca jaty F. SMITH), and Trigona (Nanno-trigona testaceicornis LEP.) while others are limited to narrow regions with special ecological conditions (e. g. M. fuscata me-lanoventer SCHWARZ). Other species still, within the same geographical region, profit different ecological conditions, as do M. marginata LEP. and M. quadrifasciata LEP. The geographical distribution of Melipona quadrifasciata LEP. is different according to the subspecies: a) subsp anthidio-des LEP. (represented in Fig. 7 by black squares) inhabits a region fron the North of the S. Paulo State to Northeastern Brazil, ,b) subspecies quadrifasciata LEP., (marked in Fig. 7 with black triangles) accurs from the South of S. Paulo State to the middle of the State of Rio Grande do Sul (South Brazil). In the margined region between these two areas of distribution, hi-brid colonies were found (Fig. 7, white circles); they are shown with more details in fig. 8, while the zone of hybridization is roughly indicated in fig. 9 (gray zone). The subspecies quadrifasciata LEP., has 4 complete yellow bands on the abdominal tergites while anthidioides LEP. has interrupted ones. This character is determined by one or two genes and gives different adaptative properties to the subspecies. Figs. 10 shows certains meteorological isoclines which have aproximately the same configuration as the limits of the hybrid zone, suggesting different climatic adaptabilities for both genotypes. The exis-tance of a border zone between the areas of both subspecies, where were found a high frequency of hybrids, is explained as follows: being each subspecies adapted to a special climatic zone, we may suppose a poor adaptation of either one in the border region, which is also a region of intermediate climatic conditions. Thus, the hybrids, having a combination of the parent qualities, will be best adapted to the transition zone. Thus, the hybrids will become heterotic and an equilibrium will be reached with all genotypes present in the population in the border region.
Resumo:
In the present work it was sougth to correlate the coloration of the fruit of Ananas comosus variety Perola with the pulp quality, aiming at the orientation of the fruit grower to the correct time of harvest. Pineapple fruit was chosen in 5 stages of maturation recognized by its external characteristics, principally its color. The fruits of each stage of maturation were analysed, determining the. weight, the percentage of soluble solids, and relation of acid to soluble solids. At the same time a test was made classifying the fruits as acid, regular, good, excellent, and spoiled. A correlation was found between the external coloration of the fruit and the degree of maturation. Concluding from this that the best time to harvest the variety Perola is in the third stage in the regions closest to the market and in the second stage in the regions which are farther away. For the cannery industry the fruit should be harvest in the first stage.
Resumo:
Sand culture experiments, using a sub-irrigation technique, were installed in order to find out the effects of the macronutrients N, P, K, Ca, Mg and S on growth, aspect, mineral composition, length of fibers, thickness of cell wall and cellulose concentration in slash pine. The aim was to obtain, under controlled conditions, basic information which could eventually lead to practical means designed to increase the rate of growth and to make of slash pine a richer source of cellulose. Nitrogen, Phosphorus, Potassium Experiment A 3 x 3 x 3 factorial design with two replicates was used. Nitrogen was supplied initially at the levels of 25, 50 and 100 ppm; phosphorus was given at the rates of 5, 10 and 20 ppm; potassium was supplied at the rates of 25, 50 and 100 ppm; six months after the experiment was started the first level for each element was dropped to zero. Others macro and all micronutrients were supplied at uniform rates. Fifteen hours of illumination per day were provided. The experimental technique for growing the slash pine seedlings proved quite satisfactory. Symptoms of deficiency of nitrogen, phosphorus and potassium were observed, described and recorded in photographs and water colors. These informations will help to identify abnormalities which may appear under field conditions. Chemical analysis of the several plant parts, on the other hand, give a valuable means to assess the nutritional status of slash pine, thus confirming when needed, the visual diagnosis. The correctness of manurial pratices, on the other hand, can be judged with the help of the analytical data tabulated. Under the experimental conditions nitrogen caused the highest increases on growth, as measured by increments in height and dry weights, whereas the effects of phosphorus and potassium were less marked. Cellulose concentration was not significantly affected by the treatments used. Higher levels of N seemed to decrease both length of fiber elements and the thickness of cell wall. The effects of P and K were not well defined. Calcium, Magnesium, Sulfur Experiment A 3 x 3 x 3 factorial design with two replicates was used. Calcium was supplied initially at the levels of 12.5, 25 and 50 ppm; magnesium and sulfur were given at the rates of 6, 12.5 and 25 ppm. Other macro and micronutrients were supplied at uniform rates, common to all treatments. Three months after starting the experiment the first level for each element was dropped to zero. Symptoms of deficiency of calcium, magnesium and sulfur were observed, described and recorded as in the case of the previous experiment. Chemical analysis were made, both for mineral content and cellulose concentration. Length of fibers and thickness of cell wall were measured. Both calcium and magnesium increase height, sulfur failing to give significant response. Dry weight was beneficially affected by calcium and sulfur. The levels of calcium, magnesium and sulfur in the needles associated with deficiency and maximum growth are comparable with those found in the literature. Cellulose concentration increased when the level of sulfur in the substrate was raised. The thickness of cell wall was negatively affected by the treatments; no effect was observed with regards to length of fibers.
Resumo:
Magdeburg, Univ., Fak. für Naturwiss., Diss., 2015
Resumo:
The present paper refers to a research work carried out at the Dept. of Agriculture and Horticulture of ESALQ, University of São Paulo, in Piracicaba, State of São Paulo (latitude 22º42'S, longitude 47º33' WG and altitude 546 m). Sowing at different times and using artificial cover, an attempt was made to evaluate the behavior of cultivar IAC 17 of cotton (Gossypium hirsutum L.) as to production and quality of fiber relating to incident solar radiation. Incident solar radiation, as well as insolation during the trial period, were tabulated and compared with yelds and agricultural and technological characters of fibers. The treatment under cover showed a mean level of incident solar radiation equivalent to less than 20% of that at clear sky, causing a decrease in cotton production and in the agricultural and technological characters of fibers.
Resumo:
Otto-von-Guericke-Universität Magdeburg, Fakultät für Naturwissenschaften, Univ., Dissertation, 2015
Resumo:
v.72:no.7(1978)
Resumo:
v.59:no.2(1971)
Resumo:
The genus Sporophila (Cabanis, 1844) unites about 30 species of small seedeaters that predominantly inhabit open or semi-open areas in the Neotropical region. The taxonomy of this group is based on morphological studies from collected male specimens. The dynamic spatial and temporal variation in the male plumage and lack of knowledge of their vocalizations make it difficult to properly diagnose some species even today, so these two aspects account for the existing taxonomic dilemmas involving Sporophila. During a four-year field study, we investigated the natural history of a breeding population of Sporophila melanogaster (Pelzeln, 1870). This is an endemic species in Brazil, which reproduces in the high-altitude grasslands of the Atlantic Forest biome. We found four male specimens with clearly diagnosable plumage, distinct from the typical form of the species. Here we describe this previously unreported plumage form. Based on the evaluation of habitat use, vocalization, and reproductive behavior, we tested two hypotheses regarding its taxonomic status. We concluded that this is another case of an intra-specific color morph within the seedeaters of the "capuchinos" group.
Resumo:
The dynamics of the bird community in a small forest fragment was evaluated along seven years in relation to changes in the surrounding landscape. The study area is an Araucaria forest fragment in Southern Brazil (state of Paraná). The sampling period covered the years 1988 through 1994 and the mark-release-recapture method was utilized. The landscape analysis was based on Landsat TM images, and changes in exotic tree plantations, native forest, open areas (agriculture, pasture, bare soil, and abandoned field), and "capoeira"(native vegetation < 2 m) were quantified. The relationship between landscape changes and changes in abundance diversity of forest birds, open-area birds, forest-edge birds, and bamboo specialists was evaluated. Richness estimates were run for each year studied. The richness recorded in the study area comprised 96 species. The richness estimates were 114, 118 and 110 species for Chao 1, Jackknife 1 and Bootstrap, respectively. The bird community varied in species richness, abundance and diversity from year to year. As for species diversity, 1991, 1993 and 1994 were significantly different from the other years. Changes in the landscape contributed to the increase in abundance and richness for the groups of forest, open-area and bamboo-specialist species. An important factor discussed was the effect of the flowering of "taquara" (Poaceae), which contributed significantly to increasing richness of bamboo seed eaters, mainly in 1992 and 1993. In general, the results showed that landscape changes affected the dynamics and structure of the bird community of this forest fragment over time, and proved to have an important role in conservation of the avian community in areas of intensive forestry and agricultural activities.
Resumo:
Fidena callipyga n. sp. is described from three specimens, in the collections of the INSTITUTO OSWALDO CRUZ. It is related to Fidena ornata kröb., 1931 and Fidena aureopygia Kröb., 1931. It can be distinguished from both by the postfrons which is comparatively broader in relation to the high, by the light golden-yellow color of the beard, in striking contrast to the hairs on the propleurae and anterior coxae, and by the extent of the golden-yellow on the abdomen. In size, ornamentation and principally in the form of the palpi it is nearer to aureopygia. Fidena callipyga n. sp. and Melpia miniatistola (End.), 1925 constitute a pair of convergent forms, they differ however not only as to hairs on the mesonotum, femora and hind tibiae and form of the abdomen, but also as to the color of the beard.