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Articles by R.C.L. Costa
Total Records ( 7 ) for R.C.L. Costa
  A.K.S. Lobato , C.F. Oliveira Neto , R.C.L. Costa , B.G. Santos Filho , F.J.R. Cruz and H.D. Laughinghouse IV
  The aim of this experiment was to investigate the responses caused by progressive water stress and the necessary time for have biochemical and physiological changes of Vigna unguiculata (L.) Walp. cv: manteguinha during the vegetative phase. Leaf Relative Water Content (LRWC), Nitrate Reductase Activity (NRA), free proline, total soluble carbohydrates, free amino acids and total soluble proteins were quantified. The plants under the control treatment maintained stable variables; however, those under water stress suffered an increase of 97.3% in proline due to osmotic adjustment, increase of 78.4% in free amino acids, caused by the break down of proteins by protease enzymes, increase in total carbohydrates by 94.2% due to a decrease in the photosynthetic capacity and low synthesis of sucrose used for exporting this solute. There was a decrease in 25.7% of the leaf relative water content in virtue of low water availability in the soil, reduction of 43.8% in Nitrate Reductase Activity (NRA) due to the regulation of this enzyme being induced by its substratum and 47.3% of total proteins due to the paralyzation of protein and proteolytic protein degradation, being maximized the variations in the parameters evaluated according to the increase in the period the plants were exposed to water stress. Physiological changes can be carried out in only a few days. However, biochemical responses should be evaluated starting at 4 days under water restriction.
  A.K.S. Lobato , R.C.L. Costa , C.F. Oliveira Neto , B.G. Santos Filho , F.J.R. Cruz , J.M.N. Freitas and F.C. Cordeiro
  The aim of the experiment was to investigate and evaluate morphological changes provoked by the progressive water stress on Leaf Relative Water Content (LRWC), height of plant, number of leaves, shoot dry matter, root dry matter in plants of soybean cultivar sambaiba. The experimental design was at randomized entirely factorial, with 2 hydric conditions (stress and control) and 4 stress points (0, 2, 4 and 6 days). It were showed in the plants under water stress drop in LRWC of 81.5 until 60.9% due water deficiency in substrate, the number of leaves increase at both the treatments, it being showed after of 6 days the increase of 24.2 and 44.8% in the plants under stress and control, respectively. It was showed different behavior of the root dry matter in plants under water stress, with higher root matter until the 2 days and lower matter after of this point, when compared with control plants. The study with soybean cultivar sambaiba under progressive water stress reveal that occurred reduction in the parameters from the experiment beginning, however significant morphological changes in the number of leaves and root dry matter were showed only after 6 days of water restriction.
  R.C.L. Costa , A.K.S. Lobato , M.A.M. Neto , B.G. Santos Filho , W.J.M.S. Maia , C.F. Oliveira Neto , A.G.T. Barreto , R.S. Lemos and D.D.S. Gouvea
  The aim of this research is to describe the morpho-anatomy of Euterpe oleracea Mart. seed. The samples with 30 seeds (0, 10, 30 days after the beginning of the germination process), in which the seeds were placed in plastic boxes with sand as substrate and immediately introduced in germination chamber under 30 °C, being irrigated daily with distilled water. The morphological and anatomical observations of the seed were carried out in the times 0, 10 and 30 and 0 days of germination, respectively. This seed has ruminated endosperm, solid, besides being constituted by large cellular walls, with several pit primary fields. The testa is ruminated, constituted by fine cellular walls, divided in three layers (external, medium and internal), it being that the medium layer has vascular bundles. The embryo is conic, basal and axial linear, with two regions, being a proximal (hypocotyl-radicle axis) and other distal (cotyledon).
  R.C.L. Costa , A.K.S. Lobato , C.F. Oliveira Neto , P.S.P. Maia , G.A.R. Alves and H.D. Laughinghouse
  The aim of this study was to evaluate and compare the effects of water stress on biochemical and physiological parameters of Vigna unguiculata (L.) Walp. (Sempre verde and Pitiuba), as well as reveal the cultivar that better adapts under water stress. The experimental design was randomized entirely in factorial, with 2 cultivars (Sempre verde and Pitiuba), combined with 2 water conditions (stress and control). Tenors of proline, free amino acids, total soluble carbohydrates and total soluble proteins were quantified and the nitrate reductase activity was measured. The plants submitted to stress suffered an increase in the amounts of proline, since this solute is an osmotic adjuster. There was an increase in the amounts of amino acids due to an increase in the protease enzyme activity and an increase in the total carbohydrate levels, caused by the increase of starch. A decrease in the amounts of total protein caused by the decrease in their synthesis and a fall in nitrate reduction activity caused by the low nitrate influx were reported. These responses were seen in both cultivars. The Pitiuba cultivar presented responses that show better osmotic adjustment in these conditions, revealing a greater adaptability of this cultivar in conditions of hydric stress.
  A.K.S. Lobato , R.C.L. Costa , M.A.M. Neto , C.F. Oliveira Neto , B.G. Santos Filho , G.A.R. Alves , K.C. Costa , L.I. Silva , T.V. Conrado and M.P. Maleia
  The aim of the study was to investigate the consequences provoked by the water deficit on nitrogen compounds in Capsicum annuum L. (cv. Vermelho Gigante) plants. The experimental design used was entirely randomized, with 2 water regimes (control and stress), as well as it was composed by 5 repetitions. The free ammonium levels suffered significant interference, as well as the control and stress treatments presented 25.9 and 20.1 μmol NH4+/g/DM, respectively. The proline level was significantly increased at 121.8%, when compared with control plants. The glycinebetaine level in stress plants presented significant increase at 39.8%. The total soluble proteins were in control and stress treatments were 5.72 and 3.89 mg/g/DM, respectively. The study revealed that the water deficit of 6 days was sufficient to provoke changes in all the nitrogen compounds evaluated, in which the reduction in amount of free ammonium is due to lower nitrogen influx and decrease of the total soluble proteins is promoted by the protease enzyme action. However, the proline and glycinebetaine levels in stress plants were showed accumulations, due to process of plant osmotic adjustment.
  A.K.S. Lobato , L.M. Luz , R.C.L. Costa , B.G. Santos Filho , A.C.S. Meirelles , C.F. Oliveira Neto , H.D. Laughinghouse , M.A.M. Neto , G.A.R. Alves , M.J.S. Lopes and H.K.B. Neves
  The aim of this study was to investigate responses promoted by external application of silicon on nitrogen components in Capsicum annuum L. plants submitted to water deficiency. The experimental design was completely randomized, with 4 treatments (0, 0.25, 1.00 and 1.75 μM Si). Leaf relative water content suffered significant changes, with values of 51.9, 66.1, 68.9 and 74.4% in 0, 0.25, 1.00 and 1.75 μM Si treatments, respectively. In total soluble proteins under concentrations of 0, 0.25, 1.00 and 1.75 μM Si were obtained values of 3.8, 4.8, 5.5 and 4.9 mg g DM-1, respectively. This study suggests that exogenous silicon alleviates negative effects promoted by water deficiency on leaf relative water content, stomatal conductance, total soluble proteins, total soluble amino acids and glycinebetaine. Furthermore, the nitrate reductase activity were observed significant benefits only at the concentration of 0.25 μM Si+, however in free ammonium was no obtained improvement after silicon application. Proline level was maximized at concentrations of 1.00 and 1.75 μM Si.
  M.A.M. Neto , A.C. Conceicao , A.S. Mendes , R.C.L. Costa and A.K.S. Lobato
  The aim of this study was to determine if the crystals of the calcium oxalate present in the Euterpe oleracea embryo has function of calcium reserve during the germination process and if the accumulation is dependent of fruit production. In the experiment 1 the design was entirely randomized, with 3 evaluation periods (September, November and December). In the experiment 2 the design was entirely randomized, with 3 treatments (without cultivation, MS-CaCl2 after 30 cultivation days and MS + CaCl2 after 30 cultivation days). The results not confirm the function of calcium reserve of the raphides in Euterpe oleracea embryos, however was determined that the calcium oxalate crystals of the embryo are monohydrated and that the production and accumulation is dependent of the season, in which the accumulation is higher in the period of smaller fruit production.
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