963 resultados para leaves
Resumo:
2016
Resumo:
Photograph of author mounted on fly-leaf facing t.-p.
Resumo:
Laboratory colonies of the leaf-cutting ants Atta sexdens feed daily with leaves of Ipomoea batatas showed ant mortality and a significant decrease in the size of the fungal garden after the second week, with complete depletion of nests after 5 weeks of treatment. The mean oxygen consumption rate of these ants was higher than the control (ants collected from nests feed with leaves of Eucalyptus alba), suggesting a physiological action of the leaves of I. batatas on the ants in addition to the effect of inhibiting the growth of the fungal garden.
Resumo:
There is a lack of researches that evaluate the development and nutrient accumulation in super early genotypes of common bean for the elaboration of fertilization programs. This study aimed at characterizing the development; N, P, K, Ca and Mg accumulation by leaves; grain yield; and yield components of super early genotypes of common bean. Field experiments were conducted in a randomized blocks design, with four replications. The treatments consisted of the IPR Colibri (control), CNFC 15873, CNFC 15874 and CNFC 15875 genotypes. Plants were sampled throughout the common bean development, being divided into leaves, stems and pods. After determining the dry matter, the contents of N, P, K, Ca and Mg accumulated in leaves were estimated. At harvesting, the grain yield and yield components were evaluated. The biomass accumulation in stems and leaves occurred until the flowering stage, and then it started in the pods until harvesting. The genotypes that absorbed more nitrogen and phosphorus had a higher grain yield. The average growing season of super early genotypes was 70 days (winter) and 63 days (summer). CNFC 15874 was the most productive genotype in the winter, with grain yield similar to the IPR Colibri cultivar (control). In the summer, CNFC 15873 and CNFC 15875 achieved grain yield similar to the IPR Colibri cultivar.
Resumo:
1989
Resumo:
The bitterness intensity of beverage prepared from the leaves produced on the males and females of yerba mate (Ilex paraguariensis), grown in the forest understory and monoculture, was evaluated. The leaves were grouped by their position (in the crown and on the branch tips) and by the leaf age. The leaf gas exchange, leaf temperature and photosynthetic photon flux density were observed. Inter and intra-specific competition for light and self-shading showed the same effect on yerba mate beverage taste. All the shading types resulted in bitterer taste of the processed yerba mate leaves compared to the leaves originated under the direct sun exposure. The leaves from the plants grown in the monoculture showed less bitterness than those grown in the forest understory. This conclusion was completely opposite to the conventionally accepted paradigm of the yerba mate industries. The leaves from the tips (younger leaves) of the plants grown in the monoculture resulted a beverage of softer taste; the males produced less bitter leaves in any light environment (forest understory or in the crown in monoculture). The taste was related to the photosynthetic and transpiration rate, and leaf temperature. Stronger bitterness of the leaves provided from the shade conditions was related to the decreased leaf temperature and transpiration in the diurnal scale.
The infection of soybean leaves by Phakopsora pachyrhizi during conditions of discontinuous wetness.
Resumo:
The ability of Phakopsora pachyrhizi to cause infection under conditions of discontinuous wetness was investigated. In in vitro experiments, droplets of a uredospore suspension were deposited onto the surface of polystyrene. After an initial wetting period of either 1, 2 or 4 h, the drops were dried for different time intervals and then the wetness was restored for 11, 10 or 8 h. Germination and appressorium formation were evaluated. In in vivo experiments, soybean plants were inoculated with a uredospore suspension. Leaf wetness was interrupted for 1, 3 or 6 h after initial wetting periods of 1, 2 or 4 h. Then, the wetting was re-established for 11, 10 or 8 h, respectively. Rust severity was evaluated 14 days after inoculation. The germination of the spores and the formation of the appressoria on the soybean leaves after different periods of wetness were also quantified in vivo by scanning electron microscopy. P. pachyrhizi showed a high infective capacity during short periods of time. An interruption of wetness after 1 h caused average reductions in germination from 56 to 75% and in appressorium formation from 84 to 96%. Rust severity was lower in all of the in vivo treatments with discontinuous wetness when compared to the control plants. Rust severity was zero when the interruption of wetness occurred 4 h after the initial wetting. Wetting interruptions after 1 and 2 h reduced the average rust severity by 83 and 77%, respectively. The germination of the uredospores on the soybean leaves occurred after 2 h of wetness, with a maximum germination appearing after 4 h of wetness. Wetness interruption affected mainly the spores that had initiated the germination.
Resumo:
This study aimed to estimate heritability coefficients and genotypic correlations of mineral macronutrients in forage peanut.
Resumo:
Experiment on The Cellulolytic Activity and Volatile Fatty Acid Product of Rumen Bacteria of Buffalo and Cattle on Rice Straw, Elephant Grass, and Sesbania Leaves Substrates had been conducted at Feedstuff Laboratory of Animal Science Soedirman University. The basic design that was used in this experiment was Completely Randomized Design (CRD) with factorial pattern of 6 x 3, three replications. The bacteria isolate as the factors were cellulolytic rumen bacteria isolate of buffalo (A1, A2, and A3) and cattle (A4, A5 and A6) while the substrates (second factor) were NDF rice straw (S1), elephant grass (S2), and sesbania leaves (S3) Cell walls. The result of this experiment showed that the interaction between bacteria isolate and substrate  type were significant on pH, NDF digestibility, cellulase activity, pH was 6.28 until 6.43. The NDF digestibility range was 12.27 until 55.61 percent. The lowers of cellulase activity was 5.11 IU/ml and the higher was 24.47 IU/ml. The range of acetic acid yield was 63.37 to 307.467 mg/100 ml. Range of  propionic production was 15.17 to 352.20 mg/ 100 ml. The production of butiric acid was 8.77 to 40.87 mg/ 100 ml. The cellulase activity of cellulolytic rumen bacteria of buffalo was higher than cattle, and also their effect on NDF digestibility of rice straw, elephant grass, and sesbania leaves cell walls. The A3 of cellulolytic rumen bacteria isolate of buffalo changed cell walls substrat to volatile fatty acid was more effective than cattle, especially on cell elephant grass. Propionic and butiric acid that was produced by cellulolytic rumen bacteria isolate of buffalo more higher than cattle (Animal Production 1 (1) : 1-9 (1999)Key Words: Cellulolytic, VFA, Rumen Bacteria, Buffalo, Cattle.
Resumo:
Microclimate and host plant architecture significantly influence the abundance and behavior of insects. However, most research in this field has focused at the invertebrate assemblage level, with few studies at the single-species level. Using wild Solanum mauritianum plants, we evaluated the influence of plant structure (number of leaves and branches and height of plant) and microclimate (temperature, relative humidity, and light intensity) on the abundance and behavior of a single insect species, the monophagous tephritid fly Bactrocera cacuminata (Hering). Abundance and oviposition behavior were signficantly influenced by the host structure (density of foliage) and associated microclimate. Resting behavior of both sexes was influenced positively by foliage density, while temperature positively influenced the numbers of resting females. The number of ovipositing females was positively influenced by temperature and negatively by relative humidity. Feeding behavior was rare on the host plant, as was mating. The relatively low explanatory power of the measured variables suggests that, in addition to host plant architecture and associated microclimate, other cues (e.g., olfactory or visual) could affect visitation and use of the larval host plant by adult fruit flies. For 12 plants observed at dusk (the time of fly mating), mating pairs were observed on only one tree. Principal component analyses of the plant and microclimate factors associated with these plants revealed that the plant on which mating was observed had specific characteristics (intermediate light intensity, greater height, and greater quantity of fruit) that may have influenced its selection as a mating site.
Resumo:
Through media such as newspapers, letterbox flyers, corporate brochures and television we are regularly confronted with descriptions for conventional (bricks 'n' mortar style) services. These representations vary in the terminology utilised, the depth of the description, the aspects of the service that are characterised and their applicability to candidate service requestors. Existing service catalogues (such as the Yellow Pages) provide little relief for service requestors from the burdensome task of discovering, comparing and substituting services. Add to this environment the rapidly evolving area of web services with its associated surfeit of standards, and the result is a considerably fragmented approach to the description of services. It leaves the reality of the Semantic Web somewhat clouded. --------- Let's consider service description briefly, before discussing our concerns with existing approaches to description. The act of describing is performed prior to advertising. This simple fact provides an interesting paradox as services cannot be described exactly before advertisement. This doesn't mean they can't be described comprehensively. By "exactly", we are referring to the fact that context provided by a service requestor (and their service needs) will alter the description of the service that is presented to the discoverer. For example, a service provider who operates a cinema wants to describe the price of their service. Let's say the advertised price is $15. They also want to state that a pensioner discount and a student discount is available which provides a 50% discount. A customer (i.e. service requestor) uses the cinema web site to purchase tickets online. They find the movie of their choice at a time that suits. However, its not until some context is provided by the requestor that the exact price is determined. The requestor might state that they are a pensioner. The same is applicable for a service requestor who purchases multiple tickets perhaps on behalf of other people. The disconnect between when the service is described and when a requestor provides context introduces challenges to the description process. A service provider would be ill-advised to offer independent descriptions that represent all the permutations possible for a single service. The descriptive effort would be prohibitive.
Resumo:
Infection of plant cells by potyviruses induces the formation of cytoplasmic inclusions ranging in size from 200 to 1000 nm. To determine if the ability to form these ordered, insoluble structures is intrinsic to the potyviral cytoplasmic inclusion protein, we have expressed the cytoplasmic inclusion protein from Potato virus Y in tobacco under the control of the chrysanthemum ribulose-1,5-bisphosphate carboxylase small subunit promoter, a highly active, green tissue promoter. No cytoplasmic inclusions were observed in the leaves of transgenic tobacco using transmission electron microscopy, despite being able to clearly visualize these inclusions in Potato virus Y infected tobacco leaves under the same conditions. However, we did observe a wide range of tissue and sub-cellular abnormalities associated with the expression of the Potato virus Y cytoplasmic inclusion protein. These changes included the disruption of normal cell morphology and organization in leaves, mitochondrial and chloroplast internal reorganization, and the formation of atypical lipid accumulations. Despite these significant structural changes, however, transgenic tobacco plants were viable and the results are discussed in the context of potyviral cytoplasmic inclusion protein function.
Resumo:
Small and micro-enterprises play a significant part in most economies. However, in developing countries these enterprises have often been planned and implemented from a poverty alleviation perspective, rather than as entrepreneurial activities and growing businesses (Mead & Liedholm 1998, Toye 1993). This paper explores a model for sustainable support to micro-enterprises in a developing country context. Sustainability is critical if micro-enterprises are to grow. The traditional philanthropic model for funding micro-enterprises leaves local communities dependent on the priorities of donors which may not always be consistent with those of the community. Long term sustainability requires a move to a model that broadens the base of both economic and intellectual resources, that builds capacity as well as providing ‘start-up’ funding through mechanism such as micro-credit (Elkington & Hartigan 2008). Designing for sustainable enterprise development includes responding to the community’s priorities, investigating individual problems and solutions, encouraging agency and active involvement in goal setting, with on-going consultation and co-development of solutions. Recognising the importance of experimentation we have moved beyond existing forms to prototype new ways of working which provide continuity of financial and intellectual support for local initiatives. The paper reviews existing micro finance and microcredit practices and suggests a new approach to establish and support enterprises with financial and knowledge resources for sustainable business practices. Principles underlying such a program and the initial steps are described.
Resumo:
It is difficult to present a paradigm shift from resource efficient to ecologically sustainable design, when many students have not yet thought about what sustainability is, let alone what it implies for the design of the built environment ‘Positive Development’ requires students to think beyond green building to something that does not yet exist. The concept of ecologically positive development suggests a product, building, system or urban area that leaves the ecological base and public estate better off than if no development had occurred. For some years now, I have experimented with communicating this paradigm shift in design to students and professionals ‐ with mixed results. This paper discusses some of the challenges, failures and successes in shifting design studio work from environmentally‐sensitive to eco-positive. The framework underlying this exploration is action research. Conclusions about the success of the strategies used for overcoming perceptual barriers to new typologies of architecture are drawn from recent student feedback. The talk will show examples of student projects that attempt eco-positive development projects.