3 resultados para cerrados

em Universidade Federal de Uberlândia


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Savannah is the second biome in biodiversity in Brazil, presenting great vegetation endemism. Dipteryx alata Vog. (Fabaceae), native from this biome, is an economically important species, with an incipient market due to the lack of commercial plantations. This highlights the need to develop and provide the basis for the domestication of this species. Thus, this study determined the best conditions for in vitro establishment, multiplication, elongation and rooting of stem tips of D. alata plantlets grown vitro. Two culture media (MS and WPM) were evaluated in different salt concentrations (25, 50, 75 and 100%) for plantlet establishment. Four concentrations of 6– Benzylaminopurine (BAP) (0, 1, 2, 3 and 4 mg L-1) amended with 0.25 mg L-1 naphthalene-acetic acid (NAA) were studied for multiplication. Simultaneous elongation and rooting were studied with four concentrations of NAA (0, 1, 2, 3 and 4 mg L-1) together with 0.5 mg L-1 IBA. The variables analyzed were: shoot length (CPA), root length (CP), fresh matter (MF), dry matter (MSC), stem diameter (DC) and number of leaves (NF), 120 days after inoculation, with the exception of number of shoots, which was evaluated in the multiplication stage only. The medium MS at the original salt concentration (100%) was effective for the in vitro establishment of E. alata, resulting in greater root length (27.65 cm) and number of leaves per plantlet (26.0). The concentration of 4 mg L-1 BAP was the best one for multiplication; however, greater concentrations can boost multiplication. The effect of NAA and IBA were noticeable on in vitro elongation and rooting, with best CPA (3.14 cm) and CR (15.84 cm). Therefore, it is possible to state that the medium MS increases the success probability of in vitro establishment of stem tips of Dipteryx alata. NAA concentrations below 3 mg L-1 were favorable for in vitro development of the species, with essential characteristics for acclimatization success|.

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The average cities inserted in the areas of the Brazilian Cerrado are restructuring in the rural and urban areas in recent decades as a result of agricultural investments. Representative of this process, we chose Rio Verde due to two processes: to develop socioeconomically depending on agricultural production restructuring Cerrado after 1970 and offer average city features regional centrality and intra-urban contradictions. So we have as the problem situation the fact of Rio Verde be inserted in an agricultural region, where the restructured field creates cooperation with the agricultural industry and the tertiary sector, structuring a regional agribusiness success. However, let us doubts about the effects of the restructuring process in socio-economic and environmental terms, in relation to the field and the city. Therefore, the aim of this thesis is to contribute to the discussion about the medium- sized Cerrado cities whose functions are linked to agribusiness, and understand the logic and the effects of the restructuring process in rural and urban areas, having Rio Verde – GO as the reference for studying. Regarding the methodological practice research, it is a qualitative research, developed based on three pillars: theoretical, documentary and field. We conclude the thesis stating that the modern field, the result of agricultural production restructuring, fomented an economy specialized in agribusiness, which led to the enrichment of the field, the formation of agro-industrial complex and the formation of an average city, specializing in agribusiness, whose centrality exceeds its micro-region. In terms of effects, we conclude that process agricultural production restructuring, generated positive impacts for the insertion of Savannahs in the national economy, and to the cities inserted in the modern field. On the other hand, country and city inserted in agricultural regions, masked under the agribusiness speech, perverse effects of socioeconomic and environmental order, is an inviting system to invest and exclusionary, when there is nothing to offer. Thus, the problems are choked on site, leaving only the speech of wealth to be disclosed in the national order.

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Light varies widely in both time and space in forest formation of “Bioma Cerrado”. Cybistax antisyphilitica occurs in areas typical of this biome, such as cerrado sensu stricto, “cerradões”, and altered areas. The aim of this study was to understand the morphological and physiological responses of C. antisyphilitica to alterations in light intensity. Juvenile plants (5 month of age) were taken to a fragment of semideciduous forest in Uberlândia-MG, and were divided into three treatments: 50 were maintained under the canopy (UC) 20 were kept in small gap (SG) and 20 were maintained under in full sun (FS). The daily courses of chlorophyll a fluorescence were made at the beginning, middle and end of dry season in 2015. At the end of the experiment measurements of chlorophyll content, gas exchange and growth were made. The plants showed dynamic photoinhibition as exhibited by reductions on Fv/Fm close to midday at the end of the dry season. Regarding the effective quantum yield (ΔF/Fm'), plants under FS showed reduced values that coincided with the higher values of electron transport rates (ETR). Plants under FS showed higher values of net CO2 assimilation rates, stomatal conductance, transpiration rates, water use efficiency and chlorophyll content compared to plants under UC. The stem diameter, dry mass of leaves and stem, total dry mass and relative growth rate were higher in plants under FS than plants under UC. On the other hand, plants under UC showed superior values of height, specific leaf area and leaf area ratio. Our results indicate that C. antisyphilitica has plasticity to survive in the contrasting light environments of the semideciduous forests, but this species was able to growth better under full sun conditions.