963 resultados para vegetative buds
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Three new fasciculate flowered species of Salacia L. (Celastraceae, Hippocrateoideae) from the Amazon basin are described: S. acevedoi Lombardi is distinguished by its small flowers, stamens with short filaments, disc connate to ovary, and size of fruits; S. negrensis Lombardi differs by its habit, characteristics and shape of leaves, flower diameter, features and size of stamens, and number of ovules: and S. odorata Lombardi is characterized by its long pedicels, conical flower buds, strongly adherent petals. and flat disc with fimbriate outer border.
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Three new species, Cissus nicaraguensis, C. patellicalyx, and Ampelocissus mesoamericana, are described from Nicaragua, Costa Rica, and El Salvador, respectively. Cissus nicaraguensis can be distinguished from all other Neotropical species by the combination of urceolate calyx and simple leaves. Cissus patellicalyx is recognized by its subspherical floral buds, immature fruits minutely tuberculate when dried, and the distinctly raised nerves of the abaxial leaf surface. Ampelocissus mesoamericana is characterized by lenticels, indument, and the obpyriform flower buds.
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S. elegans (Eriocaulaceae) is known in Brazil as star flower and is used economically for ornamental purposes. The fact that there is no control over its collection, brings about great damage to its population. Thus the importance of phenologic data for the conservation of the species. This paper reports the marking of 60 individuals in three different phases of development and the collection of monthly data about their phenology. S. elegans is a perennial plant with a rhizomatous stem that characterizes its vegetative growth. The pubescent leaves present in plants can prevent heat loss and their pigments can raise the ultra-violet radiation absorption. The young leaves present in plants during the begining of the dry season use rhizome reserves. Hydric scarcity may be the main reason for the mortality of the species. Vegetative growth and sexual reproduction are very important for the population's survival.,The blooming period in S. elegans occurs from om February to July and the dispersal of seeds occurs from August to December.
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In this study we present a survey on vegetative anatomy in species of Actinocephalus, Blastocaulon, Eriocaulon, Leiothrix, Paepalanthus, Philodice, Syngonanthus, and Tonina (Eriocaulaceae). Multivariate analyses were used to correlate anatomical characters to taxa and the habitats where the species occur. Root and stem anatomical characters seem to be more affected by environmental factors where these species occur, and seem of little value for delimiting major taxonomic groups within the family. Other characters in the leaves, such as epidermis with thickened wall cells, compartmented substomatal chambers, mesophyll with hypodermis, compact chlorenchyma, collenchymatous bundle sheath extensions, and numerous vascular bundles, were shown to be important for defining species clusters in Leiothrix, Syngonanthus, and Paepalanthus subg. Platycaulon. Similarly, loosely aggregated chlorenchyma caused Blastocaulon, Eriocaulon, Philodice, Syngonanthus sect. Carpocephalus, S. sect. Syngonanthus, and Tonina, genera from humid environments, to cluster. Scape characters appear to be more informative in discriminating groups. This situation probably reflects lower selection pressures determining anatomical characters of this organ.
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The initiation of glycogen synthesis requires the protein glycogenin, which incorporates glucose residues through a self-glucosylation reaction, and then acts as substrate for chain elongation by glycogen synthase and branching enzyme. Numerous sequences of glycogenin-like proteins are available in the databases but the enzymes from mammalian skeletal muscle and from Saccharomyces cerevisiae are the best characterized. We report the isolation of a cDNA from the fungus Neurospora crassa, which encodes a protein, GNN, which has properties characteristic of glycogenin. The protein is one of the largest glycogenins but shares several conserved domains common to other family members. Recombinant GNN produced in Escherichia coli was able to incorporate glucose in a self-glucosylation reaction, to trans-glucosylate exogenous substrates, and to act as substrate for chain elongation by glycogen synthase. Recombinant protein was sensitive to C-terminal proteolysis, leading to stable species of around 31 kDa, which maintained all functional properties. The role of GNN as an initiator of glycogen metabolism was confirmed by its ability to complement the glycogen deficiency of a S. cerevisiae strain (glg1 glg2) lacking glycogenin and unable to accumulate glycogen. Disruption of the gnn gene of N. crassa by repeat induced point mutation (RIP) resulted in a strain that was unable to synthesize glycogen, even though the glycogen synthase activity was unchanged. Northern blot analysis showed that the gnn gene was induced during vegetative growth and was repressed upon carbon starvation. (C) 2004 Elsevier B.V. All rights reserved.
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Numerous nymphoid reproductives were found in three field nests of Armitermes euamignathus collected in Brazil. We report here a morphological description and a biometric study of these individuals. Nymphoid replacements displayed narrow wing buds when compared with those present in nymphs from the three last instars. Thorax morphology of the nymphoids was similar to the penultimate nymphal instar (N4) or to the ultimate nymphal instar (N5), and their origin from these instars of nymphs is discussed. All the nymphoids had eyes, ocelli, and 15 antennal segments. The nymphoid females from nest 1 had different grades of physogastry and royal fat body. The nymphoid females from nests 2 and 3, the nymphoid males from all nests, and the primary king from nests 2 acid 3 had a common fat body, which is similar to that present in alates. The ovaries and the testes of nymphoids were fully mature and the corpora allata larger than those in imagoes. The mandibular glands were also enlarged in nymphoids but the tergal glands were absent. (C) 1999 Wiley-Liss, Inc.
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In the present study morphological changes occurring in the neuromuscular junctions (NMJ) of the extensor digitorum longus (EDL) and soleus muscles from albino rats (Rattus norvegicus) submitted to experimental chronic alcoholism were evaluated. Seventy two male animals aged 4 months and weighing on average 400 g were divided into three groups: control, alcoholic and isocaloric. Six rats from each group were anesthetized and sacrificed after 5, 10, 15 and 18 months. The NMJ did not show detectable morphological changes in either muscle after treatment when examined by light microscopy. With respect to the dimensions, statistical analysis demonstrated a tendency to a statistically significant treatment x time interaction for the length of soleus muscle NMJ. The ultrastructural study, however, revealed that the NMJ of the soleus muscle of animals submitted to 18 months of experimental alcoholism presented important morphological alterations. Characteristically, the NMJ of these muscles is located on an elevation on the surface of the muscle fiber, presenting a regular round, oval or elliptical shape and continuous and not very deep synaptic grooves. Approximately 30% of the NMJ of alcoholic rats are irregular in shape, with the sarcolemmal elevations typical of the synapse region being flattened on at least one side, with discontinuous synaptic grooves, and deep and punctiform contacts of the synaptic buds. These data suggest that, although skeletal muscle has a greater natural resistance against the direct or indirect effects of alcohol, some submicroscopic morphological alterations are detectable in the NMJ, especially in muscles with oxidative metabolism (soleus) following long periods of ingestion of alcohol. (C) 2002 Elsevier B.V. Ltd. All rights reserved.
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Microsporogenesis, chromosome number, meiotic behaviour and meiotic index were investigated in Dahlstedtia pinnata and D. pentaphylla, two legume species occurring largely in Brazil, in order to ascertain whether the pollen could limit fertilization events. Archesporial cells originate primary sporogenous and anther wall precursor cells, the tapetum is uniseriate, uninucleate and glandular. Tetrads are tetrahedric or decussate, and cytokinesis is of the simultaneous type. Mature pollen grains are tricolpate and bicellular. No abnormalities in microsporogenesis were found. In both species the chromosome number is n = 11, a number not reported previously. The base number for Dahlstedtia is also 11, because cytological observations include both species of Dahlstedtia. D. pentaphylla has a higher meiotic index and lower individual variation values, and it is considered meiotically stable. Its pollen grains do not limit fertilization. D. pinnata has a lower meiotic index, and the pollen is one of the factors which limit fertilization. Furthermore, D. pinnata has numerous adventitious shoots, which suggest that vegetative propagation is important in its reproductive process. (C) 2002 the Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 138, 461-471.
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In this work, the aim was to evaluate the performance of Irrigameter in the management of the irrigation water, led in the culture of the bean plant, comparatively to the use of the methods standard of stove, tensiometers, Bouyoucos, automatic meteorological station and pan Class A. Irrigameter was adjusted to the soil characteristics, culture of the bean and irrigation equipment to confection the management ruler. For direct estimation of the evapotranspiration of the culture of the bean plant in your development stadiums, Irrigameter operated inside with heights of the levels of water of the evaporatorio same to 2, 3 and 5 cm, corresponding to the stadiums of initial development, vegetative development and flowering, respectively. The humidity obtained by the standard method of stove it was adopted as reference in the comparisons of the irrigation depth. Irrigameter can be used in the management of the irrigation to determine the consumption of water directly for a culture, in any development stadium; the methods that estimate the evapotranspiration of the culture overestimated the irrigation depth recommended by the standard method of stove, happening behavior contrary with the ones that determines the current humidity of the soil.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Phenological studies are important to understand the dynamics in forest ecosystems and also to enable adequate management of their native species. In the Cerrado regions of the high Rio Grande river (south of Minas Gerais State), Caryocar brasiliense species is found in highly distinct morphological forms with variable phenology. The aim of this study was to investigate phenological patterns within and between populations of both the tree and shrub forms of the individuals and to determine any correlation with abiotic factors. Thirty-five observations of the phenophases of the vegetative and reproductive stages were recorded ever), two weeks for 18 months. The activity index was analyzed for each stage and further analyzed to see if there were associations with the climate data by using Spearman linear correlation. The species was deciduous but leaf growth became retarded during the dry season, at which point leaf flushing stopped and total leaf fall occurred throughout the rainy season. The flowering and the fruit production occurred in the rainy season. The reproductive phase can be either annual or sub-annual. The activity index showed high synchronism within populations during the first flowering in all populations studied (> 80%). Flowering and mature fruits were highly synchronized according to Spearman correlations. Tree and shrub individuals of C. brasiliense had very similar times for their phenophases. The best period for collecting mature fruits in these regions is between February and March.
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Introduction. Pitaya (Hylocereus undatus) is an exotic fruit species little known in Brazil and which needs basic studies about plant nutrition, propagation and physiology. Emphasizing the co-existence of juvenile and adult stages in the pitaya canopy, the plant is generally propagated by cuttings. Materials and methods. A completely randomized design with four treatments and five replications was adopted. Each treatment was represented by the part of the canopy from which the cutting was taken ( upper, middle and lower cutting and cuttings from young plants). The following variables were registered: % cuttings with roots, % of live cuttings, root density, root diameter, root area, root length and root dry mass. Results were submitted to variance analyses, Tukey's test at 0.01 probability error and simple correlation analysis. Results and discussion. The results indicated that the position from which the cutting is taken had a quantitative effect on rooting formation of pitaya cuttings. Juvenile cuttings presented 35% more cuttings with roots than adult cuttings. Root density, root area, root length and root dry mass depended on juvenility, the highest results being registered for juvenile cuttings, independently of the variable. Conclusion. Juvenile and adult stages co-exist in the pitaya canopy. Juvenility is an important rooting factor for red pitaya cuttings.
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From field observations on Drimys brasiliensis, principally in the Botucatu region of São Paulo State, Brazil, new data on the reproductive biology, the rhythm of growth, and the development of lateral cymose inflorescences, flowers and fruits are presented. Pollination accelerates the rate of flower-development for about 4-6 days. Pollination experiments show that D. brasiliensis is not self-sterile; because of mechanical devices the sticky pollen grains do not normally come into contact with the stigmata unless an animal pollen vector is involved. The pollinators are diurnal Coleoptera, Diptera and Thysanoptera which eat from the pollen, lick from the stigmatic exudates and (in case of the flies) probably also from the staminal glands. Fruit- and seedeaters are birds which seem to be the main dispersal agents. Establishment of new individuals normally is through seedlings, but also by vegetative propagation through plagiotropous branches which may root and separate from the mother plant. The morphological, developmental and reproductive aspects in D. brasiliensis are discussed in a wider context, compared with data from other Magnoliidae, and related to aspects of early Angiosperm evolution. © 1980 Springer-Verlag.
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Three types of imagery were evaluated for mapping drainage patterns and vegetation in a 100 000 ha area of Sao Paulo State, Brazil. The drainage measurements were drainage density, frequency of channels and texture ratio, studied on circular samples of 10 km2 for panchromatic photography and 100 km2 for radar and satellite images. The vegetation types were forest, pasture, sugar cane and rice, studied on circular samples of 100 km2. Radar images were the most convenient method to study drainage patterns and the land forms of large areas, while Landsat imagery was most efficient for the study of vegetative cover, although panchromatic photographs were the most accurate method.-from Field Crop Abstracts