Rakocevic M.,Embrapa Agriculture Informatics |
Rakocevic M.,University of Campinas |
Ferrandes R.,Embrapa Agriculture Informatics |
Marchiori P.E.R.,Agronomic Institute |
Ribeiro R.V.,University of Campinas
Proceedings - 2016 IEEE International Conference on Functional-Structural Plant Growth Modeling, Simulation, Visualization and Applications, FSPMA 2016 | Year: 2016
Climate forecasts suggest that [CO2] in the atmosphere will continue to increase, stimulated by anthropogenic actions. Artificial facilities are available to study the physiological responses of plants to high air [CO2], such as Free-Air-CO2-Enrichment (FACE) systems. The structural and ecophysiological responses to elevated air [CO2] in tree species are contradictory, due to species-dependent responses and relatively short-term experiments. After long-term cultivation (four years) under elevated air [CO2], we studied structural and photosynthetic acclimation of Arabica coffee trees (Coffea Arabica L.), with significant changes in leaf area along the vertical profile, number of metamers, leaf and whole-plant photosynthesis. We evaluated the responses of plant leaf area, total number of metamers, leaf and whole-plant photosynthesis along the plant vertical profile to elevated air [CO2], trying to reveal the acclimation of both plant structure and photosynthesis and its relevance for overall photoassimilate production during the reduced growth period. Coffee plants were grown under two [CO2] conditions since transplantation of coffee seedlings to the field: Actual (∼390 μL CO2 L-1) and elevated (actual + ∼200 μL CO2 L-1). Plants were codified following the VPlants methodology and computational modules of CoffePlant3D software, to obtain coffee mock-ups. The plants were separated in three 50 cm-thick layers in vertical profile. Leaf photosynthetic light response curves were determined under actual and elevated air [CO2]. Under elevated air [CO2]: 1) the tree leaf area was strongly reduced and this was associated with the occurrence of coffee leaf rust disease, significantly diminishing the area of the lowest and the upper plant layers; 2) leaf photosynthesis presented decreases in light compensation point and increases in the light-saturated photosynthetic rate; 3) the leaf scale photosynthesis was increased about three to four folds in the middle and upper plant layers and slightly in the lowest plant layer; and 4) the negative impact of leaf area reduction was mitigated by high whole-plant photosynthesis during the dry tropical winter conditions. The possible response pattern of Arabica coffee plants growth under the complex scenarios of long term elevated air [CO2] integrated structural and functional modifications and mitigated the negative impacts of leaf loss and winter water deficit through the leaf and whole-plant photosynthesis. So, after four years under FACE conditions, Arabica coffee trees are still responsive to elevated air [CO2] at leaf or plant scales. © 2016 IEEE.
Vargas V.P.,Agronomic Institute |
Cantarella H.,Agronomic Institute |
Martins A.A.,Agronomic Institute |
Soares J.R.,Agronomic Institute |
And 2 more authors.
Sugar Tech | Year: 2014
Sugarcane crop residues from green cane harvests may affect the greenhouse gas fluxes from the soils. Therefore, it is important to understand how changes in soil moisture covered with cane trash alter the N2O and CO2 emission. The aim of this study was to evaluate N2O and CO2 emission from repacked soil columns incubated with (16 Mg ha-1) or without crop residues and N fertilizer (0 or 2.1 g N m-2), and as a function of four soil moisture levels (25, 50, 75 and 100 % of water holding capacity). For gas samplings, the columns were closed with a lid and four gas samples were taken in 20 min. The N2O fluxes increased linearly (p < 0.01) with increasing soil moisture regardless of the residue application on soil. However in the columns with trash the moisture effect, on N2O emission rates, was two-fold greater. Every 10 % increase in moisture in relation to the holding capacity resulted in losses equivalent to 790 and 1,640 μg N m-2 for the 0 and 16 Mg ha-1 crop residue rates, respectively. In conditions of low moisture (25 and 50 %), the crop residue did not increase emissions compared to the bare soil. The CO2 emission also was linearly stimulated with increasing soil moisture, regardless of crop residue application. However, the CO2 emission rate was higher with the residue. Our study indicates that the effects of crop residue on greenhouse gas emissions are exacerbated in periods with high soil moisture. © 2013 Society for Sugar Research & Promotion.
Siqueira M.V.B.M.,University of Sao Paulo |
Pinheiro T.T.,University of Sao Paulo |
Borges A.,University of Sao Paulo |
Valle T.L.,Agronomic Institute |
And 2 more authors.
Biochemical Genetics | Year: 2010
Using nine microsatellite loci, we investigated genetic structure and diversity in 83 Brazilian cassava accessions, including several landraces, in the Cerrado biome in Mato Grosso do Sul, Brazil. All nine loci were polymorphic, averaging 6.00 alleles per locus. Treating each of seven municipalities as a cassava group or population, they averaged 3.5 alleles per locus, with 97% polymorphic loci, high values for observed heterozygosity (0.32) and gene diversity (0.56). Total genetic variability was high (0.668), and most of this genetic variability was concentrated within municipalities (0.577). Cluster and structure analyses divided accessions into two major clusters or populations (K = 2). Also, a significant genetic versus geographic correlation was found (r = 0.4567; P < 0.0260). Migratory routes in the Cerrado are considered main contributors to the region's high cassava diversity and spatial genetic structure, amplifying interactions between traditional farmers and the evolutionary dynamics of this crop. © 2010 Springer Science+Business Media, LLC.
Resende E.C.O.,Agronomic Institute |
Martins P.F.,University of Sao Paulo |
de Azevedo R.A.,University of Sao Paulo |
Jacomino A.P.,University of Sao Paulo |
Bron I.U.,Agronomic Institute
Brazilian Journal of Plant Physiology | Year: 2012
'Golden' papayas at maturity stage 1 (15% yellow skin) were chosen to study selected oxidative processes, the activity of antioxidant enzymes and lipid peroxidation in storage at 22°C, during the ripening of the fruit. An increase in ethylene production was observed on the second day of storage and it was followed by an increase in respiration. An increased activity of catalase, glutathione reductase and ascorbate peroxidase was observed concurrently or soon after this increase in ethylene production and respiration. The increased activity of these enzymes near the peaks of ethylene production and respiration is related to the production of oxidants accompanying the onset of ripening. On the fourth day of storage, there was an increased lipid peroxidation and decreased activities of catalase, glutathione reductase and superoxide dismutase. Lipid peroxidation induces the increase of antioxidant enzymes, which can be verified by further increases in the activities of catalase, glutathione reductase, superoxide dismutase and ascorbate peroxidase. Unlike the other antioxidant enzymes, the ascorbate peroxidase activity in the pulp increased continuously during ripening, suggesting its important role in combating reactive oxygen species during papaya ripening. With regard to physical-chemical characteristics, the soluble solids did not vary significantly, the acidity and ascorbic acid contents increased, and hue angle and firmness decreased during storage. The results revealed that there was variation in the activity of antioxidant enzymes, with peaks of lipid peroxidation during the ripening of 'Golden' papaya. These results provide a basis for future research, especially with regard to the relationships among the climacteric stage, the activation of antioxidant enzymes and the role of ascorbate peroxidase in papaya ripening.
PubMed | Paulista University, Agronomic Institute and São Paulo State University
Type: Journal Article | Journal: PloS one | Year: 2016
The present study aimed to evaluate the effect of seasonal and diurnal events on the chemical profile of the essential oil obtained from the leaves of Copaifera langsdorffii Desf. This study was performed in a Brazilian savanna named Cerrado. We identified the best harvesting period for obtaining the highest amount of compounds used for commercial and industrial purposes. The chemical profile of the essential oils was evaluated by GC-FID and GC-MS, and the results were assessed through multivariate analyses. The data showed that the time of day and seasonal variations affect the quality of the essential oil obtained. Leaves harvested at the end of the day (5:00 pm) in the dry season resulted in richer essential oils with higher amounts of non-oxygenated sesquiterpenes. To the best of our knowledge, environmental conditions induce metabolic responses in the leaves of C. langsdorffii, which changes the patterns of sesquiterpene production. Therefore, these factors need to be considered to obtain better concentrations of bioactive compounds for pharmacological studies.
Fernandes K.F.M.,Agronomic Institute |
Berton R.S.,Agronomic Institute |
Coscione A.R.,Agronomic Institute
Plant, Soil and Environment | Year: 2014
The addition of essential elements to human health by mineral fertilization is considered a promising strategy for biofortification. A greenhouse experiment was carried out where amounts equivalent to 0.0; 0.5; 1.0 and 2.0 kg/ha of selenium (Se), as sodium selenite, were added to two soils with contrasting textures to evaluate the increase in Se concentration on the edible parts of rice (grain) and radish (roots) plants. Two extractors (KCl and KH2PO4) were also evaluated in their efficiency in predicting available Se to the two species. Total Se concentration in plants increased significantly with the amounts of Se added to both soils showing that selenite can be used for biofortification of these crops. Selenium availability was higher on sandy soil than on sandy clay soil. Se extraction with KCl presented better performance than KH2PO4 in predicting Se phytoavailability for rice and radish.
Montanari R.,State University of Mato Grosso do Sul |
Souza G.S.A.,State University of Mato Grosso do Sul |
Pereira G.T.,São Paulo State University |
Marques Jr. J.,São Paulo State University |
And 2 more authors.
Precision Agriculture | Year: 2012
Spatial sampling designs used to characterize the spatial variability of soil attributes are crucial for science studies. Sample planning for the interpolation of a regionalized variable may use several criteria, which could be best selected from an estimated semivariogram from a previously established grid. The objective of this study was to optimize the procedure for scaled semivariogram use to plan soil sampling in sugarcane fields in the Alfisol and Oxisol regions of Jaboticabal Town in São Paulo State, Brazil. A scaled semivariogram for several soil chemical attributes was estimated from the data obtained from two grids positioned on a sugarcane field area, sampled at a depth of 0.0-0.5 m. The research showed that regular grids with uniform intervals did not express the real spatial variability of the soil attributes of Oxisols and Alfisols in the study area. The calculated final sampling density based on the scaled parameters of the semivariogram was one sample for each 2 ha in Area 1 (convex landscape) and one sample for each 1 ha in Area 2 (linear landscape), as indicated by SANOS 0.1 software. The combined use of the simulation programs and scaled semivariograms can be used to define sampling points. These results may help in soil fertility mapping and thereby improve nutrient management in sugarcane crops. © 2012 Springer Science+Business Media, LLC.
Lima T.C.,Federal University of Sergipe |
da Silva T.K.M.,Federal University of Sergipe |
Silva F.L.,Federal University of Paraiba |
Barbosa-Filho J.M.,Federal University of Paraiba |
And 4 more authors.
Chemosphere | Year: 2014
The aim of this study was to evaluate the larvicidal activity of Mentha x villosa essential oil (MVEO) and its major constituent, rotundifolone, against larvae of Aedes aegypti. Additionally, a set of 15 analogues of the rotundifolone were evaluated to identify the molecular characteristics which contribute to the larvicidal effect. The results from the present study showed that the MVEO exhibited outstanding toxic effects against Ae. aegypti larvae (LC50=45.0ppm). Rotundifolone exhibited reasonable larvicidal activity (LC50=62.5ppm). With respect to comparative study of rotundifolone and its analogues, all tested compounds were less potent than rotundifolone, except (-)-limonene. In general, replacement of C-C double bonds by epoxides groups decreases the larvicidal potency. The presence of α,β-unsaturated carbonyls contributes to the larvicidal toxicity. The addition of hydroxyl groups in the chemical structure resulted in less potent compounds. Furthermore, the enantioselectivity seems to play an important role for the larvicidal toxicity. © 2013 Elsevier Ltd.
PubMed | Federal University of Sergipe, Agronomic Institute and Federal University of Paraiba
Type: | Journal: Chemosphere | Year: 2014
The aim of this study was to evaluate the larvicidal activity of Mentha x villosa essential oil (MVEO) and its major constituent, rotundifolone, against larvae of Aedes aegypti. Additionally, a set of 15 analogues of the rotundifolone were evaluated to identify the molecular characteristics which contribute to the larvicidal effect. The results from the present study showed that the MVEO exhibited outstanding toxic effects against Ae. aegypti larvae (LC50=45.0ppm). Rotundifolone exhibited reasonable larvicidal activity (LC50=62.5ppm). With respect to comparative study of rotundifolone and its analogues, all tested compounds were less potent than rotundifolone, except (-)-limonene. In general, replacement of C-C double bonds by epoxides groups decreases the larvicidal potency. The presence of ,-unsaturated carbonyls contributes to the larvicidal toxicity. The addition of hydroxyl groups in the chemical structure resulted in less potent compounds. Furthermore, the enantioselectivity seems to play an important role for the larvicidal toxicity.
PubMed | Wageningen University, Federal University of Ceará, Agronomic Institute and University of Campinas
Type: | Journal: Journal of plant physiology | Year: 2016
Spraying sucrose inhibits photosynthesis by impairing Rubisco activity and stomatal conductance (g