Recomendacoes tecnicas sobre gergelim; regiao Centro-Sul do Brasil. EMBRAPA. Centro Nacional de Pesquisa do Algodao (Campina Grande, PB). DESEMPENHO AGRONÔMICO DE GENÓTIPOS DE GERGELIM (Sesamum indicum L.) SOB Pesquisadora, Doutora, EMBRAPA, CNPA, Campina Grande. O trabalho foi realizado em dezembro de , na Embrapa Algodão, de onde foram retirados discos foliares de gergelim para serem mensurados os índices.
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Physiological, biochemical and productive changes in sesame genotypes subjected to different rates of water replenishment. The sesame crop has stood out due to the high nutritional content of its seeds, in addition to being able to be cultivated in the tropical and subtropical regions such as Northeast Brazil.
Thus, it is necessary to identify the physiological, biochemical and productive changes related to the tolerance to stress. Objective of this study was to evaluate the physiological, biochemical and productive aspects of sesame genotypes as a function of different rates of water replenishment.
Data corresponding to the following variables were collected: The genotypes did not differ statistically and there were differences in the variables between the water replacement rates.
Nevertheless, in these regions, irrigation can be used to supplement rainfall, which leads to improvement in the growth, development and yield of crops.
According to Bernardo et al. Additionally, these authors highlight that cultivation success depends embrapx supplemental irrigation during the critical period of the crop. Sesame Sesamum indicum L. The sesame crop is resistant to drought and can produce with mm of water well distributed along the cycle Bernardo et al.
In the last years, many studies have been carried out using sesame, usually involving spacing, plant density and irrigation Pinto et al. However, no studies were found on the determination of physiological and biochemical variables in genotypes of sesame under different water depths. In this context, this study aimed to evaluate the physiological, biochemical and productive behavior of sesame genotypes as gergepim function of different rates of water replacement.
Non destructive analysis of photosynthetic pigments in leaves of Sesamum indicum (L.)
The region has mean rainfall of mm, mean gegelim temperature of Along the experimental period, temperature, relative humidity, wind speed and rainfall data Table 1 were collected at the Embrapa Cotton Meteorological Station, in Barbalha-CE. The experiment was conducted in a clayey soil, sampled until cm deep and classified as clay loam Fluvic Neosol RYwhose textural and physical characterizations were performed at the Irrigation and Salinity Laboratory of the Academic Unit of Agricultural Engineering of the Federal University of Campina Grande.
For soil chemical characterization, according to the methodology of Carmo et al. The experimental embrapz comprised four embra;a, and the two central rows were used for evaluations. Tillage in the experimental area consisted in one plowing and four cross harrowing procedures, using a leveling harrow.
Irrigation management was performed using the water depth principle, based on the replacement of reference evapotranspiration ETo for two consecutive days.
Processo de elaboração de extrudados não expandidos (pellets) de milho e sementes de gergelim.
Irrigation depth Li and irrigation time Ti were calculated according to Mantovani et al. The sesame genotypes used were white and creamcolored, all developed by the Embarpa Agricultural Research Corporation Getgelim Cotton. Their main characteristics include: All evaluations, except of production, were carried out at 90 days after emergence DAE. Total leaf area cm 2 was determined by measuring the length and width of leaflets and using the equation proposed by Silva et al.
Leaf relative water mebrapa was measured according to Smart amp; Bingham Cell membrane integrity evaluation, based on electrolyte leakage, was expressed as percentage of conductivity in relation to the total conductivity.
Chlorophylls ab and total, and carotenoids were extracted using the solvent dimethyl sulfoxide Hiscox amp; Israelstam, At 50 DAE, leaf samples were collected to emvrapa enzymatic activity: At 95 DAE, harvest was done manually by cutting the whole plant at soil level.
Then, plants were air-dried for seven days to facilitate the removal of seeds from the capsules. Yield was estimated based on the production obtained in the evaluation area of the experimental plot.
Oil content in the seeds was quantified by nuclear magnetic resonance NMRbased on non-destructive tests, in which embrapw value found results from the magnetic field scanning of the sample Oxford Instruments, Data of the response variables were subjected to the analysis of gergelij by F test Fisher at 0. Quantitative factors irrigation depth were subjected to polynomial regression analyses, selecting the model of highest significance in the F test Ferreira, Analyses were carried out using the statistical programs Sisvar 5.
Table emrbapa shows the analysis of variance summary for the growth physiological, biochemical and production variables. For the interaction irrigation depth x genotypes, there was no significance. Maximum points of LA Increased water replacement in the soil resulted in decreases of This behavior demonstrates sesame sensitivity to both deficit and excess of water in the soil.
Similar response was found by Silva et al. These results corroborate the hypothesis that sesame is sensitive to water stress. Plant water relationships have been widely investigated under water deficit conditions, and leaf water content is accepted as an indicator of plant water conditions. In the sesame genotypes evaluated here, the maximum estimated relative water content RWC The reductions in RWC observed here were lower than those reported by Pinto et al.
The increase in embdapa leakage as soil water content decreased can be attributed to a consequence of the limitation in photosynthesis imposed by the water deficit, which results in disruption of membrane integrity, triggered by the overproduction of reactive oxygen species ROS. High contents of these compounds can reduce the activity of enzymes, cause peroxidation of lipids, oxidation of rmbrapa and, in the most advanced stage, kill the cell Gergflim et al.
For electrolyte leakage ELthe data of the sesame genotypes fitted to a decreasing linear model and maximum estimated value Water deficit is closely related to the loss of pigments and, consequently, to vergelim reduction in the photosynthetic and productive capacity of plants.
Hence, analysis of photosynthetic pigments is essential to evaluate the health and integrity of internal cell apparatus during photosynthesis Taiz amp; Zeiger, ; Rigon et al.
Recomendacoes tecnicas sobre gergelim; regiao Centro-Sul do Brasil.
In the sesame plants evaluated, chlorophyll contents ab and total fitted to a quadratic polynomial model Figure 3A, B and C and their maximum estimated values Chlorophyll is one of the main factors related to plant photosynthetic efficiency and, ebmrapa, to growth and adaptability to different environments and conditions caused by the various types of stress.
Gergelmi bconsidered as accessory pigment, is a biochemical compound present in the chloroplasts that help light absorption.
Its production is directly associated with chlorophyll a production Silva et al. Such behavior may indicate that sesame plants are more susceptible to the stress caused by excess of water than the one caused by its absence, corroborating the claim of Arriel et al. For the content emgrapa carotenoids, maximum estimated value Determining the content of carotenoids in plants subjected to some sort of stress is very important, due to their role in the dissipation of the energy intercepted.
These pigments act as photoprotectors, deactivating singlet and triplet oxygen by absorbing the energy present in these compounds during their formation, which prevents oxidative damages to plant cells Engel amp; Poggiani, ; Taiz amp; Zeiger, embrpaa Brito et al. In embraapa context, it can be inferred that plants with lower contents of this pigment would be more subject to damages caused by the excess of light to the photosystem.
Recomendacoes tecnicas sobre gergelim; regiao Centro-Sul do Brasil.
Nevertheless, reduction in carotenoids combined with low content of chlorophyll a in the leaves of plants subjected to both absence and excess of water may contribute to increasing the injuries to the photosynthetic mechanism, leading to limitations in growth, development and production.
Plants protect their cells and subcellular compartments from cytotoxic effects caused by ROS by using antioxidant enzymes, such as catalase and peroxidase. In natural environment, antioxidative responses to abiotic variations are induced by similar mechanisms, which result in adaptations to drier or more humid periods, to days with higher or lower light incidence, as well as to high and low temperatures, since these factors lead to the increase in ROS contents and, consequently, stimulate likewise antioxidant activity Sharma et al.
According to Sharma et al. Maximum estimated activity Such reduction in the activity of the enzymes in plants subjected to water stress conditions may be an indication of non-adaptation to the stressful environment, with effect on crop yield.
Maximum yields found with intermediate water depths may be directly associated with the improvements observed in physiological and biochemical processes, such as the water content in the leaves. In addition, yield reduction is directly related to the water stress conditions, because plants use the stomatal closure mechanism to protect themselves from water losses through transpiration, leading to a reduction in the photosynthetic rate Taiz amp; Zeiger, Oil content in the seeds increased with the increment in water replacement until the estimated water depth of Nonetheless, increment in water depth above Sesamol, with its antioxidant properties, promotes high chemical stability in the oil, preventing rancidification.
In this context, sesame oil content becomes one of the most important variables to evaluate the gedgelim of the crop from the agronomic geegelim of view. Sesame genotypes did not differ statistically and there were differences in the variables between the water replenishment rates. To the Brazilian Agricultural Research Corporation Embrapa Cotton for providing the structure needed to conduct this study. In special, to Dr. O produtor pergunta, a Embrapa responde. Non-destructive analysis of photosynthetic pigments in cotton plants.
Activation of systemic disease resistance in pea by an avirulent bacterium or a benzothiadiazole, but not by a fungal leaf spot pathogen. Revista Brasileira de Fisiologia Vegetal, v. Biochemical and developmental characterization of multiple forms of Catalase in tobacco leaves.
A method for the extraction of chlorophyll from leaf tissue without maceration. Canadian Journal of Botany, v. Crescimento e produtividade da cultura do gergelim Sesamum indicum L. Reactive oxygen species, oxidative damage, and antioxidative defense mechanism in plants under stressful conditions. Journal of Botany, v. Revista de Oleaginosas e Fibrosas, v.
Rapid estimates of relative water content. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Services on Demand Journal. ABSTRACT The sesame crop has stood out due to the high nutritional content of its seeds, in addition to being able to be cultivated in the tropical and subtropical regions such as Northeast Brazil. Results and Discussion Table 2 shows the analysis of variance summary for the growth physiological, biochemical and production variables. Depth L 3 Conclusions Sesame genotypes did not differ statistically and there were differences in the variables between the water replenishment rates.
Literature Cited Arriel, N. May 04, ; Accepted: How to cite this article.