Acta Scientiarum Agronomy
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/11111
Navegar
5 resultados
Resultados da Pesquisa
Item Drying of arabica coffee and its effect on the gene expression and activity of enzymes linked to seed physiological quality(Editora da Universidade Estadual de Maringá - EDUEM, 2023) Carvalho, Mayara Holanda de; Rosa, Sttela Dellyzete Veiga Franco da; Coelho, Stefânia Viias Boas; Guimarães, Cristiane Carvalho; Martins, Rayana de Sá; Clemente, Aline da Consolação Sampaio; Paiva, Luciano VilelaThe reduced longevity of coffee seeds has been attributed to their sensitivity to desiccation. Studies related to gene expression and enzyme activity in coffee seeds under drying are important for understanding the effects of drying on their physiological quality. The aim of this study was to investigate the molecular aspects of seeds under different drying methods and associate them with physiological quality. Coffee seeds with different water contents were dried both slowly and rapidly. Enzymatic activity was analysed, as well as the expression of genes that encode the enzymes superoxide dismutase, catalase, peroxiredoxins, isocitrate lyase, and endo-ß-mannanase. There was a significant effect of drying speed and final water content on enzyme activity and on the expression of the different genes analysed. In seeds under rapid drying, there was greater expression of the genes that encode the enzymes catalase and endo-ßmannanase. Greater expression of the 1 CYS PRX and SOD genes and greater activity of the ICL isoenzymes were found in seeds with superior physiological quality, but greater activity of the endo-β-mannanase and CAT enzymes occurred in seeds with lower physiological quality.Item Proposed diagrammatic scale to assess heat injury in coffee seedling canopy(Editora da Universidade Estadual de Maringá - EDUEM, 2023-04-28) Resende, Laís Sousa; Pozza, Edson Ampélio; Pereira, Renata Cristina Martins; Botrel, Élberis Pereira; Roteli, Karolaine de Cássia; Oliveira, Júlia MarquesA diagrammatic scale with five levels (0, 0.1 - 2.0, 2.0 - 6.0, 6.0 - 10, and 10 - 14) was developed and evaluated to measure the symptoms of heat injury in a coffee seedling canopy. The scale was constructed to increase assessment efficiency and align the estimations more closely with the actual values. Two assessments with the diagrammatic scale and one without were conducted with an interval of seven days. The evaluators using the proposed scale presented estimates with better levels of precision, accuracy, reproducibility, and repeatability than those using a conventional method. The proposed diagrammatic scale was shown to provide a reliable estimate for assessing the symptoms of heat injury on the canopy of in Coffea arabica L. seedlings. Therefore, it is possible to standardize heat injury evaluation methods using this diagrammatic scale, allowing for data comparisons with different cultivars.Item Leaf area index and radiation extinction coefficient of a coffee canopy under variable drip irrigation levels(Editora da Universidade Estadual de Maringá - EDUEM, 2019) Costa, Jéfferson de Oliveira; Coelho, Rubens Duarte; Barros, Timóteo Herculino da Silva; Fraga Junior, Eusímio Felisbino; Fernandes, André Luís TeixeiraThe leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.Item Microclimate in coffee plantation grown under grevillea trees shading(Editora da Universidade Estadual de Maringá - EDUEM, 2011-04) Pezzopane, José Ricardo Macedo; Souza, Paulo Sérgio de; Rolim, Glauco de Souza; Gallo, Paulo BollerMeasurements of solar global radiation, wind speed, temperature and relative humidity of air were made in a coffee plantation (Coffea Arabica L. variety Icatu Vermelho- IAC 4045), grown under conditions of shading levels caused by grevillea trees (Grevillea robusta) in Mococa-SP region (21o 28’ S, 47o 01’ W, altitude 665m), between January and December 2005, aiming to show the effects of shading crop system on the microclimate. The results showed that there was a reduction of about 26% of solar global radiation in the shaded systems, with a monthly variation of 24-30%. It has been highlighted some differences in the transmittance of global radiation in the shaded coffee trees due to the spatial variation of grevillea canopy. There was a reduction of about 35% in the five days-averaged wind speed in the shaded system that also presented reduced maximum air temperature and a reduction in the vapor pressure deficit during day-light period, especially in the point sampled near to the grevillea trees.Item Water use efficiency by coffee arabica after glyphosate application(Editora da Universidade Estadual de Maringá - EDUEM, 2014-07) Carvalho, Felipe Paolinelli de; França, André Cabral; Souza, Bruna Pereira de; Fialho, Cíntia Maria Teixeira; Santos, José Barbosa dos; Silva, Antonio Alberto daMany coffee growers apply glyphosate in directed applications, but some phytotoxicity has been noted. It is believed some herbicides can exert a direct or indirect negative effect on photosynthesis by reducing the metabolic rate in a way that can affect the water use efficiency. The objective of this study was to investigate the variables related to water use among coffee cultivars subjected to the application of glyphosate and the effects of each dose. The experiment was conducted in a greenhouse using three varieties of coffee (Coffea arabica), Acaiá (MG-6851), Catucaí Amarelo (2SL) and Topázio (MG-1190), and three doses of glyphosate (0.0, 115.2 and 460.8 g acid equivalent ha-1 ), in a factorial 3 x 3 design. At 15 days after application, a reduction in stomatal conductance was observed, and smaller transpiration rate and water use efficiency were found in the fourth leaf at 15 days after application. There was a decrease in the transpiration rate at 45 DAA, with the Acaiá cultivar showing reductions with 115.2 g ha-1 . There was transitory reduction in water use efficiency with glyphosate application, but can affect the growth and production. The Acaiá cultivar showed the highest tolerance to glyphosate because the water use efficiency after herbicide application.