https://ri.ufs.br/jspui/handle/riufs/2152 2026-07-11T02:08:53Z https://ri.ufs.br/jspui/handle/riufs/25414 Título: O escurecimento e a cicatrização em inhame (Dioscorea spp.) minimamente processado é modulado pela região do tubérculo, aplicação de ácido ascórbico e temperatura de conservação Autor(es): Corrêa, Cristina Bani Abstract: Mechanical damage caused by peeling and cutting affects the biochemical and physiological processes of yam, triggering enzymatic oxidation and inducing rapid defense responses, such as the formation of structural barriers at the wound site. This study aims to investigate, in an integrated manner, the physiological, biochemical, and structural responses of minimally processed yam (Dioscorea cayenensis), evaluating the effects of tuber region, storage temperature, and ascorbic acid application on enzymatic browning and wound healing. Slices from the apical (AP), medial (ME), and distal (DI) regions were subjected to minimal processing, treated or not with ascorbic acid (1% w/v), and stored at 5 °C (browning) and at 5 and 20 °C (lignification). Quality and physicochemical parameters, phenolic metabolism, enzymatic activities (PPO, SOD, CAT, POD, and PAL), and lignin deposition were evaluated. Visual quality progressively declined during storage, with more pronounced losses in the apical region. ascorbic acid delayed browning and extended the acceptability of the medial and distal regions. Browning dynamics were modulated by polyphenol oxidase (PPO) activity, superoxide dismutase (SOD), and phenolic content, indicating that when enzymatic protection becomes insufficient, phenolic compounds act as non-enzymatic antioxidants. Chromatographic analysis revealed selective accumulation of hydroxycinnamic acids and flavonoids, indicating activation of the phenylpropanoid pathway in response to post-processing stress. The wound healing process was strongly influenced by temperature. At 5 °C, an antioxidant response predominated, with no detectable lignin deposition. In contrast, at 20 °C, increased activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD) were observed, along with lignin deposition, characterizing a structural response. Overall, the results demonstrate that the quality of minimally processed yam is determined by the interaction between tuber region, storage temperature, and ascorbic acid application, highlighting the multifactorial nature of oxidative stress regulation in minimally processed yam. 2026-02-26T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25411 Título: Atividade antimicrobiana e antibiofilme de óleos essenciais de Lippia gracilis e seus compostos majoritários sobre fitopatógenos do gênero Xanthomonas spp. resistentes ao cobre Autor(es): Gois, Larissa de Souza Abstract: The genus Xanthomonas is formed by gram-negative phytobacteria that produce biofilms and that cause diseases in plants of economic importance. Prominent diseases include black rot of crucifers, water belly of melon, gummosis of sugar cane, bacterial leaf streak of corn, and bacterioses of cassava and plum. Due to the need for new alternatives for treatment of these diseases, essential oils (EOs) have been studied, which are plant secondary metabolites that have different biological activities, such as antibacterial activity. The objective of this study was to evaluate the antimicrobial and antibiofilm activity of EOs from seven accessions of Lippia gracilis Schauer (LGRA-106, 107, 108, 109, 110, 201, and 202) obtained through the hydrodistillation technique and their major compounds thymol and carvacrol, as well as evaluate copper resistance in five species of phytobacteria of the genus Xanthomonas: Xanthomonas campestris pv. melonis, Xanthomonas axonopodis pv. manihotis, Xanthomonas campestris pv. pruni, Xanthomonas axonopodis pv. vasculorum, and Xanthomonas campestris pv. campestris. Using spectrophotometric techniques, Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), antibiofilm activity, cell viability, plasma membrane permeabilization, and resistance to sulfate and copper oxide were evaluated; and the biofilm was morphologically examined under microscopy in vitro. scanning electronics. The in vivo study was carried out in an agricultural greenhouse. The effect of the EO from the LGRA107 accession (previously selected for its greater bacteriostatic and bactericidal activity against X. campestris pv. campestris) and the effect of copper oxide were examined on two varieties of kale plants (Georgia and Ramoso Santana) inoculated with Xanthomonas campestris pv. campestris regarding the following variables: number of leaves, biomass, and incidence and severity of disease. The in vitro experiments were performed in duplicate with three replications. For the in vivo experiment, a completely randomized design was used in a 2 × 3 factorial arrangement, constituted by two inoculation methods (injected and sprayed) and three substances (two concentrations of EO from the LGRA-107 accession – 250 and 500 µg mL-1 , and a copper oxide concentration – 2000 µg mL-1 ). A control of 1% DMSO was also used. For analysis of disease severity and incidence, a scoring scale from 0 to 5 was used, and evaluations were carried out over a period of 15 days. The concentration of 1000 µg mL-1 of EOs from LGRA accessions and the major compounds thymol and carvacrol at concentrations between 250 and 500 µg.mL-1 , respectively, demonstrated bacteriostatic and bactericidal activity and led to an increase in cell plasma membrane permeability bacterial. The EOs of all accessions, as well as the major compounds and copper oxide, showed antibiofilm activity for the five phytobacteria. However, this activity was not observed for copper sulfate. As the result of the in vivo experiment, kale, when exposed to copper oxide, obtained higher values of fresh biomass, and broccoli kale had higher leaf numbers. The results of this study showed that the essential oils of the accessions LGRA-109, LGRA-201, and LGRA-107 had greater antimicrobial activity and are promising for control of phytobacteria of the genus Xanthomonas spp. 2022-07-29T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25370 Título: Prospecção, conservação, caracterização genética, química, morfoagronômica e sazonalidade em germoplasma de Croton blanchetianus Baill Autor(es): Costa, Rosemeire Santos Abstract: Croton blanchetianus Baill. is a medicinal and aromatic species native to the Caatinga biome, widely distributed in the Brazilian Northeast. It is notable for its high bioactive and apicultural potential, and it is listed by the Ministry of Environment as a priority species for the region due to its potential economic importance. Nevertheless, its natural occurrence area is frequently reduced, primarily due to anthropogenic interventions. In view of the imminent threats to the species’ genetic variability, the Federal University of Sergipe (UFS) studied natural populations and subsequently established a collection of C. blanchetianus in its Active Germplasm Bank (AGB) for Medicinal and Aromatic Plants at UFS. This initiative allows the development of strategies for conservation and sustainable use of the species. The present research aims to evaluate the genetic and chemical diversity of natural populations of C. blanchetianus from municipalities in the state of Sergipe, as well as to establish a collection, characterize the accessions morpho-agronomically, chemically, and seasonally, and assess the antioxidant activity of the accessions conserved in the AGB. In the first article, the genetic diversity and structure of six natural populations of C. blanchetianus from different municipalities in the state were evaluated, using ISSR markers. Low genetic variability among populations (6%) was observed, and it was not possible to differentiate genotypes according to their geographic origin. In the second article, the chemical diversity of the essential oil from 70 genotypes of C. blanchetianus, collected from six natural populations in Sergipe, was evaluated. The major compounds found were α-pinene (1.60–13.37%), limonene (0.30–17.54%), β-phellandrene (4.38–16.04%), 1,8-cineole (0.16–13.56%), (E)-caryophyllene (0.31–13.14%), germacrene D (0.33–10.60%), bicyclogermacrene (5.06–27.47%), and spathulenol (4.34–29.83%), highlighting the broad chemical diversity of the species. In the third article, the morphoagronomic and chemical diversity of 26 C. blanchetianus accessions was characterized and analyzed. High variability among accessions was observed for all evaluated morpho-agronomic descriptors, particularly plant height (87.00–236.50 cm), crown diameter (48.75–131.00 cm), leaf area (74.50–176.37 cm²), dry mass (83.17–333.00 g/plant), and essential oil content (0.60– 1.60%). Chemically, the accessions were mostly comprised of α-pinene (3.90–12.02%), limonene (0.88–10.72%), β-phellandrene (1.30–17.51%), 1,8-cineole (0.36–11.57%), (E)- caryophyllene (1.82–12.48%), germacrene D (0.38–10.12%), bicyclogermacrene (8.37– 29.13%), and spathulenol (5.57–28.04%). In the fourth article, the chemical profile of the essential oil from leaves and fruits of five accessions of C. blanchetianus was analyzed, revealing quantitative and qualitative differences between plant organs. Leaves had a predominance of sesquiterpenes (37.34–62.03%), whereas fruits had higher levels of monoterpenes (23.97–61.03%). The exclusive presence of myrtenyl acetate in fruit essential oil indicates its potential as a chemical marker. In the fifth article, the seasonal influence (three harvest periods) on agronomic variables, chemical composition, and antioxidant activity of essential oil from 26 accessions of C. blanchetianus was evaluated. Accessions CBL-403 and CBL-503 showed the highest oil content (1.93%), while CBL-503 (17.41 g/plant) and CBL507 (17.38 g/plant) exhibited the highest essential oil yields. Sesquiterpenes predominated in harvests 1 and 2 (59.02% and 62.01%, respectively), while monoterpenes increased in harvest 3 (40.01%). A high antioxidant potential was observed in accession CBL-301 (DPPH: 66.24%; ABTS: 92.51%). These results indicate that C. blanchetianus exhibits exploitable genetic, morpho-agronomic, and chemical variability, and that its essential oils show seasonal plasticity and antioxidant activity. 2026-02-24T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25369 Título: Fenotipagem por Vant e aprendizado de máquina para predição da produtividade de milho em ambientes contrastantes de nitrogênio em região semiárida Autor(es): Santos, Barbara Nascimento Abstract: High-throughput phenotyping has contributed substantially to advances in agriculture and plant breeding programs. By using unmanned aerial vehicles (UAVs), its application has enabled the rapid acquisition of phenotypic data with high reliability and spatial resolution, promoting its adoption across diverse agricultural contexts. Despite these advances, several methodological limitations remain insufficiently explored, particularly when this approach is applied under conditions of environmental stress and high spectral homogeneity. This study aims to evaluate the accuracy of four predictive models, using regression and machine learning approaches to estimate the grain yield of maize half-sib progenies grown under contrasting nitrogen conditions, based on multispectral images obtained by UAV. The experiments were conducted during the 2024 growing season in two experimental areas located in the municipalities of Nossa Senhora da Glória and Graccho Cardoso, Sergipe, Brazil. A randomized block design with split plots and three replications was adopted, in which nitrogen levels (high and low) were assigned to the main plots and the half-sib progenies to the subplots. Multispectral drone images were acquired during three flights at heights of 60 and 80m throughout the crop cycle, corresponding to different phenological stages. Fourteen multispectral vegetation indices associated with canopy structure, chlorophyll content, and plant nutritional status were calculated. Four predictive approaches were evaluated: a classical linear model, a penalized regression model (LASSO), and two decision tree-based algorithms, Conditional Forest (Cforest) and Gradient Boosting Machine (GBM). Model performance was evaluated using the root mean square error (RMSE) and the mean absolute error (MAE), in addition to diagnostic analyses of the linear model assumptions and assessments of variable importance and SHAP values for the GBM and Cforest models. In both experimental areas and nitrogen conditions, the Cforest and GBM models consistently showed higher predictive accuracy than the linear approaches. Overall, images acquired at 60m resulted in superior model performance, highlighting the importance of higher spatial resolution for increased sensitivity to physiological variability within the canopy. Analyses of variable importance and SHAP values indicated that predictive contributions were concentrated in a limited subset of vegetation indices, particularly those sensitive to canopy structure and chlorophyll content. Furthermore, distinct predictive responses were observed among genotypes, depending on the modeling approach and environmental conditions. These results suggest that the acquisition and processing of spectral data can be optimized by prioritizing specific vegetation indices and strategically selected phenological stages. For predicting maize grain yield, the combined use of the Cforest and GBM models with vegetation indices such as TCARI, MCARI, and MSAVI2 is recommended. To increase the robustness and generalizability of these findings, future studies should evaluate the performance of such indices across a broader range of nitrogen levels, genotypes, and edaphoclimatic conditions. 2026-01-26T00:00:00Z