Claudia Petry

Porosidade e retenção de água em um argissolo sob manejos convencional e direto submetido a compressões unidimensionais

To date, little is known about the dynamics of water and air in porous spaces of soils exposed to mechanical stresses, mainly when the pressure is located on the pre-consolidation line. This study aimed to quantify the changes in the porous spaces of an Acrisol under two tillage systems, submitted to increasing one-dimensional compression, emphasizing the bulk density and water retention at two water potential levels. Undisturbed soil samples were collected under conventional tillage (CT) and no-till (NT), with three replications, from the Ap surface horizon (0-0.075 m) of an Red-Yellow Dystrophic Acrisol at the Universidade Federal de Santa Maria in Rio Grande do Sul State. The sample water content was standardized at -32 kPa in a Richards membrane-plate extractor and the samples were submitted to one-dimensional pressures of 0, 50, 100, and 200 kPa in an open-drained oedometric cell. After the trial, clods were pushed by hand and were submitted in four replications to two water potential levels (-1.600 and -100 kPa) in a Richards membrane (cell). Sample volumes as well as gravimetric water contents were determined by weighing in kerosene after oven-drying at 105 °C. ANOVA was performed as well as regression analysis, whenever necessary. The response of soil bulk density to the increasing pressure was a linear function for SPD and a square function for SPD. In both management systems the water content was exponentially related with the stress levels. Variation in water retention can be explained by 85 % by the one-dimensional compression, which was positive for CT and negative for NT. At a water potential of -100 kPa the changes in bulk density and gravimetric water content were relevant in both management systems. It was concluded thatthe soil under CT is more sensitive to mechanical stress than that under NT, as demonstrated in the magnitude of reduction of porous space and air proportion contained within.

Response to water deficit of Ipomoea cairica (L.) Sweet

Green spaces require frequent watering, increasing the pressure on water resources. The use of native plants in landscaping reduces the risks of biological contamination, contributing to preservation of Brazilian biodiversity and provides the value of sustainability in urban green areas. Of these native plants, a restricted number are native lianas which are adapted to Brazilian climate and available on the market. In this regard, the selection and recommending of native plants which are efficient in use of water for planting in urban areas constitute an effective strategy for conservation of water resources. Thus, the purpose of this study was to evaluate the growth and development of I. cairica plants submitted to water deficit. For a period of 100 days after transplanting, plants of this species were grown with watered at pot capacity except for 30 days (from the 30th to the 60th day) when four water deficits (25, 50, 75 and 100% pot capacity) were applied. During all regimes of water deficiency applied, there was a 100% survival rate. After reestablishment of water regime the species recovered its growth, even that was submitted to the 25% of pot capacity. It testify that I. cairica is resistant to low water availability.

Charcacterization of the anatomy of leaves and inflorescenses of the Lavender species (Lamiaceae) used as medicine in Brazil.

Plants of the genus Lavandula denominated communly as lavenders are aromatic originated in Europe, especially from the Mediterranean area and belonging to the Lamiceae group. There is little information about the anatomy of plants of this gender, so we prioritized to identify the anatomical characters of Lavandula angustifolia Mill and Lavandula dentata L. to assist their own identification. For the historical analysis it was performed the middle part of young leaves and inflorescences in full bloom, from transverse sections made freehand with the help of razor and Styrofoam and the help of optical microscope and common digital camera (Olympus SP – 800UZ). It was also performed paradermical scraping with freehand from the abaxial surface of leaves and inflorescences and macerated dried material analysis of these organs. We sought to identify and classify the trichomes, the anatomical characteristics of leaves and inflorescences (flowers and bracts), and the powder of these agencies to compare the results obtained. In the anatomical characters examined, both from fresh material as the macerated material, there were similarities between the two species and morphology of epidermal cells, cuticle, stomata types, and heterogeneous dorsiventral mesophyll, and glandular trichomes in the leaves. L. dentata presents two larger secondary vessels conductors in the middle part of the leaves, while in angustifolia L. these vessels are all identical and with smaller gauges.

Cobertura de solo e produção de porongo sob diferentes configurações de cultivo

In small farms, the traditional cropping system on slope and shallow soils is often common, resulting in soil and water degradation and low productivity. The study aimed to investigate different configuration of cultivations (density and times of sown) of Lagenaria siceraria (Mol.) Standl. species (bottlegourd), intending to promote faster soil mulching, to increase productivity and to obtain better quality of marketable fruits. Three experiments in completely randomized design with four replicates were installed at 15/09/07, 06/10/07 and 27/10/07 in the northern Rio Grande do Sul in a Red Latosol under conventional tillage system (SPC). The sown was made on holes with 2.5x2.5 and 5.0x5.0m spacing, considered traditional, and with 1,600 and 400 holes ha-1 density, respectively. It was evaluated the crop cycle, the number and length of main stems 60 days after emergence (DAE), the soil mulching at 0, 30, 60, 90 and, 150DAE and, quality and fruit productivity. A joint analysis of data from experiments showed that the plants sown on 27/10/07, in both spacing, showed lower cycle (150 days), fruit size and productivity, but under 1,600 holes ha-1 (2.5x2.5m of sown spacing), there was at 30DAE a faster soil mulching (93.7%) than in other sown times. In the same holes density, at any time of sown, it was shown that 2.5x2.5m spacing, reaches the faster soil mulching and higher yield of fruits than those under traditional sown density.

Contribuição de constituintes de solo à capacidade de troca de cátions obtida por diferentes métodos de extração

The cation exchange capacity (CEC) is a physicochemical property dependent on mineral and organic soil constituents. Despite the use of different procedures and extractors the CEC is normally expressed considering only the pH control or not of the extracted solution. This study aims to discuss the significance of the contribution of organic carbon and clay to the CEC of an Acrisol, using different determination methods. For this purpose, 75 samples of an abruptic Red-Yellow Acrisol from the Universidade Federal de Santa Maria campus were used, representing five layers and five land use and management systems, in triplicate. The CECE was estimated by cobalt hexamine trichloride (CECE Cohex) and by the sum of cations Al3+ , Ca2+, Mg2+, and K+ (CECE SB+AlKCl), the first three extracted by KCl and the last by Mehlich-1; the CEC7 was estimated by ammonium acetate (CEC7 Metson) and the sum of bases Ca2+ , Mg2+and K+ and H+Al was estimated by the SMP index (CEC7 SB+H+AlSMP). The CEC values obtained with the different methods are correlated, with coefficients of determination over 0.93. The CEC7 Metson values are subestimated when compared with those by CEC7 (SB+H+AlSMP). The contribution of clay and organic carbon to CEC7 was, respectively, 23 and 399 cmolc kg-1 for CEC7 (SB+H+AlSMP) and 19 and 256 cmolc kg-1 for CEC7 Metson. The contribution of the soil constituents depends on the extracting cation and the performance of the extraction methods employed.

Composição centesimal e perfil dos ácidos graxos de sementes de porongo

The fruit of bottlegourd are used for the manufacture of gourd, utensils and handicrafts. Seeds and fruits of bottlegourd are discarded during the manufacturing in producing regions. Thus, this study aimed to evaluate the composition and profile of fatty acids in the seeds of bottle gourd with a view to using the seeds as raw material and food. Seeds of bottle gourd, whose plants were seeded in different growing seasons, were collected in an experiment in the city of Rondinha - RS, in 2008. After drying, it was separated and the ratio of peel and seed kernels. The almonds were subjected to assessment of lipid content, ash, crude protein, crude fiber and carbohydrates. The fatty acid composition of lipids present in the almonds was determined by gas chromatography. The seeds had high carbohydrate content (33.0%), lipids (37.6%) and protein (25.2%), but were not affected by seeding date. However, plants seeded later (on October 27th ) had shorter cycle (time between seeding and senescence of plants, 149 days) and almond had a higher relative proportion of fatty unsaturated acids (79.5%). The predominant fatty acids in decreasing order were linoleic acid (C18: 2, omega-6), palmitic acid (C16: 0), oleic (C18: 1, omega-9) and stearic acid (C18: 0). The results of centesimal composition and profile of fatty acids suggest a nutritional potential that needs to be better studied with a view to exploiting the bottle gourd seeds.