https://repositorio.ufu.br/handle/123456789/18960 Tue, 07 Apr 2026 12:42:35 GMT 2026-04-07T12:42:35Z https://repositorio.ufu.br/handle/123456789/47773 Title: Regeneração natural em fragmentos de cerrado sensu stricto: padrões ecológicos e aspectos silviculturais de Eugenia involucrata como uma espécie-alvo Abstract: The cerrado sensu stricto, formerly the most extensive phytophysiognomy of the Cerrado biome, has undergone intense conversion to agriculture and livestock production, resulting in fragmentation and varying levels of environmental disturbance. In this context, the present study aimed to characterize the structural patterns of the woody community, evaluete the natural regeneration potential in three fragments (F1, F2, and F3), analyze the regenerative status of Eugenia involucrata and investigate the initial growth and morphophysiological traits of its seedlings under nursery and experimental conditions. Natural regeneration was sampled in two plot classes: tem plots of 10 × 10 m (Class I) and tem plots of 2 × 2 m (Class II), arranged along transects perpendicular to the drainage line. For each species, density, frequency, and the Total Natural Regeneration index (RNT) were calculated, with RNT also determined separately for E. involucrata. A total of 501 regenerating individuals were recorded in F1, 321 in F2, and 153 in F3. The most conserved fragment (F1) exhibited greater species richness and density, with Fabaceae, Myrtaceae, and Malpighiaceae being the most prominent. In F2, Fabaceae, Myrtaceae, Chrysobalanaceae, and Connaraceae were most representative in Class I, while in F3, Fabaceae, Anacardiaceae, Annonaceae, Chrysobalanaceae, and Myrtaceae predominated across both classes. Species such as Miconia albicans, E. involucrata, Matayba guianensis, and Connarus suberosus showed the highest RNT values, indicating strong natural regeneration potential under contrasting environmental conditions. The occurrence of exclusive species across fragments highlighted environmental heterogeneity and differing responses to disturbance. E. involucrata accounted for 113 individuals across the three fragments, with significant differences in density and consistently high RNT values, confirming its robust regenerative performance. Early development of the species in the nursery was examined through two experiments. Experiment I (Matrix) used seeds from three mother trees originating from two fragments, resulting in three treatments (M1, M2, and M3). Height, stem diameter, leaf number, fresh and dry biomass of shoots and roots, MSPA/MSR ratio, Dickson Quality Index (DQI), leaf area, mesophyll structure, stomatal conductance, and chlorophyll content were evaluated at 180 and 300 days. Significant differences among treatments indicated variation in seedling vigor, likely associated with genetic or environmental differences among matrices. In Experiment II (Sun and Shade), seedlings were subjected to full sunlight or shading for 30 days. Only chlorophyll content differed significantly between treatments, although all seedlings exhibited similar growth patterns and high survival rates, highlighting the species’ marked physiological plasticity in response to light availability. Overall, the results demonstrate that E. involucrata possesses high plasticity and strong natural regeneration capacity, reinforcing its suitability for ecological restoration programs in degraded cerrado sensu stricto areas. Thu, 26 Aug 2021 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/47773 2021-08-26T00:00:00Z https://repositorio.ufu.br/handle/123456789/47766 Title: Estratégias de defesa contra a megafauna extinta em fitofisionomias do Cerrado brasileiro Abstract: This study investigates the influence of the extinct South American megafauna on plant anti- herbivory defenses across different vegetation types of the Cerrado biome. We hypothesized that the nature and prevalence of defensive strategies are determined by the interaction between resource availability, particularly soil fertility, and historical herbivory pressures exerted by megafauna. To test this, we compiled functional trait data for woody species of the South American tropical flora from published literature, including leaf size, wood density, specific leaf area, leaf nitrogen, spinescence, and latescence. These data were combined with indicator species lists for savanna, dystrophic “cerradão” forest, mesotrophic “cerradão” forest, deciduous forest, semideciduous forest, and evergreen forest, and analyzed in relation to environmental conditions. Statistical analyses included Principal Component Analysis (PCA) of environmental variables across vegetation types and Bayesian hierarchical regression models for plant defensive traits. Our results show that Cerrado plant defenses arise from the interaction between current environmental conditions and the evolutionary legacy of herbivory. In fertile soils, such as those of deciduous forests, physical defenses predominate, characterized by reduced leaves and high spine density, protecting nutrient-rich tissues from large herbivores. In savannas, low leaf nutritional quality functions as the main defense mechanism, without reliance on small leaves or high spinescence. Dystrophic “cerradão” forest exhibited increased latex production and dense leaves, indicating chemical and structural defenses against smaller herbivores. These findings confirm that plant defenses in the Cerrado are heterogeneous and shaped by its mosaic of vegetation types: fertile environments favor physical defenses protecting nutritious leaves, whereas nutrient-poor environments promote chemical and structural strategies adapted to herbivory by smaller fauna. Overall, this study highlights the combined role of historical and contemporary factors in shaping plant defensive traits in the Cerrado. Fri, 29 Aug 2025 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/47766 2025-08-29T00:00:00Z https://repositorio.ufu.br/handle/123456789/47750 Title: O papel do cotilédone no estabelecimento de plântulas: estudo de caso Ricinus communis L. (Euphorbiaceae) Abstract: The period of seedling establishment is a susceptible phase in the life cycle of plants, due to high mortality rates in this stage. The morphology of the cotyledons indicates what function it will have in the seedling. Cotyledons positioned above the ground by the elongation of the hypocotyl give rise to an epigeal seedling. These cotyledons can be thin with leaf-like morphology. Seedling phanerocotylar epigeal foliaceous (PEF) rapidly expand their cotyledons favouring photosynthetic activity. Premature loss of photosynthetic cotyledons can lead to increased mortality in the seedling phase. The objective of the present work is to experimentally 6 study the function of the photosynthetic cotyledon in the establishment of seedlings, using as a model Ricinus communis, a PEF seedling. It is intended to evaluate how different degrees of cotyledon removal will influence the growth and photosynthetic performance in R. communis seedlings. Ricinus communis seeds, collected near the Umuarama campus of the Federal University of Uberlândia, underwent pre-germination treatments to accelerate the germination process. The seeds were sown in 2 L pots with a mixture of soil, sand and substrate in the condition of 2: 1: 1. After seedling emergence, the cotyledons were removed forming four treatments with 20 repetitions each: 100% (control: intact seedlings), 50% (seedlings with total removal of just one cotyledon), 25% (seedlings with total removal of a cotyledon, plus 50% of the second cotyledon) and seedlings with total removal of the cotyledon area. Measurements of chlorophyll a fluorescence and Falker chlorophyll index were performed on the remaining cotyledons on the 1st, 3rd, 8th, 14th and 25th days after removing the cotyledons (DAR) and the measurements of leaf gas exchange were carried out on the 7th DAR. To analyse the growth of seedlings on the treatments applied, height, stem diameter, leaf area, dry mass, and relative growth rate were measured. In three moments of the experiment, cotyledons were collected for analysis of the structure of the cotyledon mesophyll. The values of the electron transport rate (ETR) in the treatments of 50% and 25% of the cotyledon area were higher than those of the control. Likewise, photosynthesis was superior in seedlings with 50% of the cotyledon area in relation to intact seedlings. The Falker chlorophyll indexes remained close until the 14th DAR, however the treatment with 25% of the cotyledon area exceeded to the other treatments. The loss of part of the cotyledons had a negative impact on seedling growth. Both, biomass accumulation as well as the relative growth rate decreased as the removal of cotyledons was more intense. Although it is possible to identify physiological compensation in seedlings with the removal of cotyledons, the smaller area of cotyledons present in the seedlings was not enough to balance the growth of the manipulated seedlings in relation to the control seedlings. 7 The results show the dependence of photosynthetic activity of cotyledons during initial establishment in seedlings of Ricinus communis. Mon, 17 Feb 2020 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/47750 2020-02-17T00:00:00Z https://repositorio.ufu.br/handle/123456789/47728 Title: Estudos sobre estratégias adaptativas e traços funcionais no Cerrado lato sensu Abstract: The Cerrado lato sensu, the second largest biome in South America, is recognized as one of the world’s biodiversity hotspots, harboring high species richness and a mosaic of physiognomies ranging from open grasslands to dense forest formations (RIBEIRO; WALTER, 2008, p. 151). As Klink and Machado (2005, p. 708) state, “the Brazilian Cerrado harbors about 5% of global biodiversity, representing a natural heritage of global relevance.” According to Rodrigues et al. (2009, p. 4): The Cerrado is one of the most threatened ecosystems in the world due to agricultural expansion, habitat fragmentation, and biodiversity loss. The urgency to understand its ecological dynamics is proportional to the intensity of anthropogenic pressures it has been facing. In this context, this dissertation aims to analyze, from the perspective of functional ecology, the adaptive strategies and functional traits that confer resilience to plant species in the Cerrado lato sensu in response to natural environmental filters and anthropogenic pressures. Violle et al. (2007, p. 883) define functional traits as “morphological, physiological, or phenological attributes that directly influence species’ performance in response to environmental conditions.” The research consisted of a systematic literature review based on the PRISMA protocol (MOHER et al., 2009, p. 2), covering publications between 2000 and 2025. The review included studies addressing morphological traits (height, specific leaf area, wood density, underground7 structures), physiological traits (photosynthetic rates, stomatal conductance, water use), and phenological traits (flowering, fruiting, leaf senescence), in relation to environmental factors such as fire, acidic soils, water seasonality, and anthropogenic degradation. The results show that species from different physiognomies share adaptive traits such as low specific leaf area (SLA), deep roots, the presence of xylopodia, thick bark, and conservative resource-use strategies (GRANT et al., 2014, p. 355). These attributes reflect the action of environmental filters such as nutrient-poor soils and recurrent fire, which select highly adapted species (SILVA et al., 2013, p. 220). It is concluded that the functional approach applied to the Cerrado lato sensu not only enhances the understanding of its ecological mechanisms but also represents a strategic tool to support conservation, management, and ecological restoration policies (MARTINS et al., 2020, p. 5). Thu, 31 Jul 2025 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/47728 2025-07-31T00:00:00Z