Use of gibberellin in floriculture

This review aimed to show the use of gibberellin in floriculture. In this context, it should be noted that the benefit of the activity of the gibberellins has brought major advances in the field of physiology. Its use is one of the most important tools for the development of agriculture. Thus, the study concluded that the use of gibberellins has been increasingly used by producers and is also a vast important subject that may help in increasing the production of flowers if the farms are dedicated to this purpose.Keywords: Regulators plants, flowers, phenotypic characteristics, postharves

Nutritional composition and phenolic compounds and nitrate content in eatable vegetables obtained by conventional and certified organic grown culture

The aim of this work was to analyse some nutritional characteristics in eatable vegetables obtained by conventional and organic grown culture, focusing on vegetable parts that are generally rejected by consumers. Samples of Chinese cabbage (Brassica rapa (syn. B. campestris) spp. pekinensis)) and maize (Zea mays L.) had been analysed under raw conditions and after thermal treatment in order to test modifications in protein, lipids, carbohydrate, phenol, nitrate content and dry weight. According to our results, thermal treatment modified some characteristics. Even if for most parameters significant differences between foods obtained by the two cultivation procedures had not been observed, in organic samples a higher concentration of nitrate was found. Furthermore, domestic processing, such as cooking in boiling water, seems to have a dramatic effect on phenolic content on both kinds of food, and, as a consequence, on antioxidant activity

Can hydrogen peroxide and quercetin improve production of Eucalyptus grandis x Eucalyptus urophylla?

Vegetative propagation is considered the best choice for the rapid multiplication of plant species, however, rooting may still present difficulties. Substances, such as auxins, phenolic compounds and hydrogen peroxide, are recognized as able to improve this process. The aim of the present work was to determine if hydrogen peroxide in combination with quercetin or indole butyric acid, can modify some characteristics related to rooting and development in cuttings of Eucalyptus grandis x Eucalyptus urophylla. Cuttings were periodically evaluated at 30, 60 and 90 days according to the following criteria: height, diameter and survival percentage. After planting (90 days), a destructive evaluation was performed to determine rooting percentage, average size and number of roots. Polyamines content and polyamine oxidase activity, as biochemical markers of plant development, were determined. No statistically significant differences in height, diameter, survival and rooting percentage, root length and number of roots per cuttings were found. Treatments induced a decrease in putrescine levels and polyamine oxidase activity in roots. For absence of positive responses, the use of these substances as a treatment to improve cutting production is economically unviable.Keywords: Phenolic compounds, indole butyric acid, vegetative propagation, cuttings.African Journal of Biotechnology Vol 13(28) 2819-282

Effect of spermidine on ornamental bromeliad cultured in vitro

Plants of the ornamental bromeliad, Aechmea blanchetiana (Baker) L.B. Smith obtained from seeds germinated in vitro, were treated with spermidine (Spd) at various concentrations (0, 10, 50 and 250 \u3bcM) or in the presence of 1.07 mM \u3b1-naphthaleneacetic acid (NAA) + 22.20 mM 6-benzyladenine (BA) or 0 mM NAA + 0 mM 6-BA for shoot induction and 0, 1.07 and 5.37 mM of NAA for root induction. The number of shoots, fresh and dry weight of shoots on shoot induction and fresh and dry weight of shoots and roots on root induction, and activity of peroxidases were evaluated. Polyamine Spd was not effective on shooting induction, rooting, mass accumulation of fresh and dry weight and had no influence on the activity of the enzyme peroxidase, and had a deleterious effect on dry matter accumulation in the treatment for shooting induction. Spd improved the qualitative and quantitative responses of in vitro rhizogenesis of A. blanchetiana as compared to the free polyamine medium. Peroxidase activity was higher in leaves of plants subjected to shoot induction, with 6-BA+NAA. The exogenous spermidine did not have effect on peroxidase activity

Endogenous and exogenous polyamines in the organogenesis in Curcuma longa L.

The present work evaluated the development of different Curcuma longa L. explants (leaves basis, root tips and ancillary buds from rhizome) stimulated by exogenous polyamines, combined with naphtalen-acetic acid (NAA) or with 6-benzyl-aminopurine (BAP), to produce callus and its subsequent differentiation. The explants, isolated from field plants, were previously subjected to a basic cleaning method and were inoculated onto Murashige and Skoog culture medium (MS) [Murashige, T.S., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiologia Plantarum 15, 473\u2013497] supplemented with NAA (2.0 mg L-1 ). Buds were subjected to different treatments, with or without 5.0 and 10.0 mmol L-1 exogenous polyamines (mixture of putrescine:spermine:spermidine, 1:1:1) combined with NAA. The calluses obtained were transferred into the same medium, supplemented with the mixture of polyamines combined with BAP, in order to induce plant differentiation. For C. longa, buds were the most efficient explants for callus induction (p < 0.05). The application of exogenous polyamines (5.0 and 10.0 mmol L-1 ) produced the most developed callus, with numerous roots. The medium supplemented with 10 mmol L-1 polyamine mixture, combined with BAP, induced good regeneration, producing vigorous plants and excellent shoot formation.Polyamines addition promoted the formation of callus, roots and leaves, representing an important factor in the determination of indirect organogenesis in C. longa L., and putrescine content may be considered a valuable marker of the differentiation process in this specie, as well as the enzyme peroxidase

Conserva\ue7\ue3o p\uf3s-colheita de manga tommy atkins com 1-metilciclopropeno

The present study had the objective of evaluating the post-harvest conservation of 'Tommy Atkins' mangoes, treated with different concentrations of 1-MCP, stored under refrigeration. The treatments were several concentrations of 1-MCP, 0, 100, 300 and 600 nL L-1, for 12 hours in isolated chambers at temperature of 25\ub0C. After opening the chambers, fruits were stored at temperatures of 25\ub0 C, 75\ub15% of RH and 10\ub0 C, 70\ub1 5% of RH for 28 days. The experimental design was a completely randomized in a factorial 4 x 6 x 2. Four repetitions were used per treatment, with five fruits per plot. The analyzed variables were the loss of mass, the firmness, the vitamin C, the total and reducer sugars and the carotenoids contents. Under the conditions in which the experiment was carried out, it can be concluded that: post-harvest applications of 1-MCP on 'Tommy Atkins' mangoes were effective in reducing the physiological metabolism of fruits maturation; 1-MCP and refrigeration associated were effective in keeping fruits stored for 28 days after harvesting; the 1-MCP concentration of 600 nL L-1 was considered the most efficient in reducing the ripening of fruits at 10\ub0C and 25\ub0C

Kinetic role of a histidine residue in the T1 copper site of the laccase from Rigidoporus lignosus

Laccases (benzendiol:oxygen oxidoreductases; EC 1.10.3.2) catalyze the oxidation of a broad range of substrates, such as polyphenols, dyes and pollutants, and thus these enzymes are widely applied in industrial, biotechnological and environmental fields. In order to improve their biotechnological applications, a deep knowledge of structural factors involved in controlling their activity, in various experimental conditions and on different substrates, is required. In the present study, a laccase from the mushroom Rigidoporus lignosus was kinetically characterized. In particular, the stability, the effects of pH, ionic strength and fluoride ion concentration on the kinetic parameters were investigated, using three di-hydroxy-benzene isomers (1,2-dihydroxy-benzene, 1,3-dihydroxy-benzene and 1,4-dihydroxy-benzene) as substrates. The catalytic constant values of the laccase showed a bell-shaped pH profile, with the same optimum pH and pKa values for all tested substrates. This behavior appears to be due to the presence of an ionizable residue in the enzyme active site. To identify this residue, the enzyme was derivatized with diethyl-pyrocarbonate to modify accessible histidine residues, which, according to structural data, are present in the active site of this enzyme. The kinetic behavior of the derivatized laccase was compared with that of the native enzyme and the derivatized residues were identified by mass spectrometry. Mass spectrometry and kinetic results suggest the main role of His-457 in the control of the catalytic activity of laccase from R. lignosus