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| Registros recuperados: 360 | |
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| Panda,S.K.; Choudhury,S.. |
| The article presents an overview of the mechanism of chromium stress in plants. Chromium is known to be a toxic metal that can cause severe damage to plants and animals. Chromium-induced oxidative stress involves induction of lipid peroxidation in plants that causes severe damage to cell membranes. Oxidative stress induced by chromium initiates the degradation of photosynthetic pigments causing decline in growth. High chromium concentration can disturb the chloroplast ultrastructure thereby disturbing the photosynthetic process. Like copper and iron, chromium is also a redox metal and its redox behaviour exceeds that of other metals like Co, Fe, Zn, Ni, etc. The redox behaviour can thus be attributed to the direct involvement of chromium in inducing... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antioxidants; Chromium; Fenton reactions; Metallothioneins; Oxidative stress. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000100008 |
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| Redgwell,Robert; Fischer,Monica. |
| This review summarises recent advances in the chemistry, physiology and molecular properties of coffee carbohydrates with a particular focus on the cell wall polysaccharides. The results of detailed chemical studies have demonstrated novel structural features of both the galactomannans and the arabinogalactan polysaccharides of the green and roasted coffee bean. For the first time immunological probes based on monoclonal antibodies for specific polysaccharide epitopes were used to reveal the patterns of distribution of the galactomannans, arabinogalactans and pectic polysaccharides in the coffee bean cell wall. Finally, the results of physiological and molecular studies are presented which emphasise the growing awareness of the potential role the metabolic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea; Cell wall; Beverage quality; Seed. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000100012 |
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| Silva,Maria do Céu; Várzea,Victor; Guerra-Guimarães,Leonor; Azinheira,Helena Gil; Fernandez,Diana; Petitot,Anne-Sophie; Bertrand,Benoit; Lashermes,Philippe; Nicole,Michel. |
| Considerable success has been obtained in the use of classical breeding to control economically important plant diseases, such as the coffee leaf rust and the coffee berry disease (CBD). There is a strong consensus that growing genetically resistant varieties is the most appropriate cost effective means of managing plant diseases and is one of the key components of crop improvement. It has also been recognized that a better knowledge of both, the pathogens and the plant defence mechanisms will allow the development of novel approaches to enhance the durability of resistance. After a brief description of concepts in the field of plant disease resistance, we attempt to give a view of the research progress on coffee leaf rust and CBD concerned with the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea; Colletotrichum kahawae; Hemileia vastatrix; Coffee breeding; Resistance. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000100010 |
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| Eira,Mirian T. S.; Silva,E. A. Amaral da; De Castro,Renato D.; Dussert,Stéphane; Walters,Christina; Bewley,J. Derek; Hilhorst,Henk W. M.. |
| Considerable advances in our understanding of coffee seed physiology have been made in recent years. However, despite intense research efforts, there are many aspects that remain unclear. This paper gives an overview of the current understanding of the more important features concerning coffee seed physiology, and provides information on recent findings on seed development, germination, storage and longevity. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea; Coffee; Germination; Germplasm; Longevity; Seed development; Storage. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000100011 |
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| Yruela,Inmaculada. |
| Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network of metal trafficking pathways, different strategies have evolved in plants to appropriately regulate its homeostasis as a function of the environmental copper level. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Copper homeostasis; Copper transporters; Detoxification; Metalloproteins; Toxicity. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000100012 |
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| De Castro,Renato D.; Marraccini,Pierre. |
| In commercial coffee species (Coffea arabica and Coffea canephora), fruit development is a lengthy process, characterized by tissue changes and evolutions. For example, soon after fecundation and up to mid development, the fruit is mainly constituted of the pericarp and perisperm tissue. Thereafter, the perisperm gradually disappears and is progressively replaced by the endosperm (true seed). Initially present in a "liquid" state, the endosperm hardens as it ripens during the maturation phase, as a result of accumulation of storage proteins, sucrose and complex polysaccharides representing the main reserves of the seed. The last step of maturation is characterized by the dehydration of the endosperm and the color change of the pericarp. Important... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea spp; Bean development; Cell cycle; Endosperm; EST; Gene expression; Pericarp; Perisperm. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000100013 |
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| Thomas,André Luís; Sodek,Ladaslav. |
| Flooding leads to hypoxia, a stress to which symbiotic N2 fixation is especially sensitive. The response of fully nodulated soybean plants to a 21-day period of flooding was studied by measurements of growth parameters and xylem transport of organic nitrogenous components to the shoot, in the presence and absence of NO3- and NH4+ in the medium. Flooding was found to seriously impair N2 fixation, irrespective of the N source, as indicated by strongly reduced xylem ureide levels. In the absence of a source of N, growth was strongly reduced during flooding while accumulation of N in the shoot was virtually abolished. Flooding in the presence of 5 mM NO3- or NH4+ led to the accumulation of total N in the shoot but only NO3- promoted increases in total dry... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glycine max; Anaerobiosis; Oxygen deficiency. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000300003 |
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| Silva,André Luiz Oliveira da; Barrocas,Paulo R.G.; Jacob,Silvana do Couto; Moreira,Josino Costa. |
| Anthropogenic activities have being contributing to the spread of toxic chemicals into the environment, including several toxic metals and metalloids, increasing the levels of human exposure to many of them. Contaminated food is an important route of human exposure and may represent a serious threat to human health. This mini review covers the health effects caused by toxic metals, especially Cd, Hg, Pb and As, the most relevant toxic elements from a human health point of view. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bioavailability; Contamination; Heavy metals; Metal toxicity. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000100007 |
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| Hameed,Asiya; Qadri,Tabasum N.; Mahmooduzzafar,; Siddiqi,T.O.; Iqbal,M.. |
| Cadmium and Mercury induced varying responses in Abelmoschus esculentus L. in relation to enzymes (ascorbate peroxidase (APX, 1.11.1.11), catalase (CAT, 1.11.1.6), glutathione reductase (GR, 1.6.4.2) and superoxide dismutase (SOD, 1.15.1.1) which are most related to the levels of Hg and Cd applied and concentrations of thiol groups already present or induced upon treatment. In the present investigation varying concentrations of CdCl2 and HgCl2 (0, 0.05, 0.10, 0.50, 1 and 2mM respectively) applied to plant in the soil shows a significant increase in ascorbate peroxidase, glutathione reductase and superoxide dismutase activities, and the respective metal accumulation. It reveals a mechanism for constant detoxification of H2O2 that have to be associated with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antioxidative enzymes; Metals detoxification; Reactive oxygen species. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202011000100007 |
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| Takahashi,Cassia A.; Ceccantini,Gregório C.T.; Mercier,Helenice. |
| The leaf is the main organ of the vegetative body of tank epiphytic bromeliads, which may be subdivided into apical and basal parts. Little is known about the existence of morphological, anatomical or physiological differences between these two leaf portions. The objective of this study was to verify the existence of a differential capacity to assimilate nitrogen from urea between basal and apical leaf portions of Vriesea gigantea, a tank epiphytic bromeliad. Plants were cultivated in vitro in the presence of 5 mM urea for 15 days. During this period, the activities of the enzymes glutamine synthetase (GS, EC 6.3.1.2) and NADH-dependent glutamate dehydrogenase (NADH-GDH, EC 1.4.1.2) were quantified, as well as the densities of trichomes and stomata found... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bromeliaceae; Glutamate dehydrogenase; Glutamine synthetase; Stomata; Trichome; Urea. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202007000200004 |
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| Aragão,Maria Erivalda Farias de; Guedes,Marjorie Moreira; Otoch,Maria de Lourdes Oliveira; Guedes,Maria Izabel Florindo; Melo,Dirce Fernandes de; Lima,Maria da Guia Silva. |
| Vita 3 and Vita 5 are two Vigna unguiculata cultivars that differ in their capacities for survival in saline environments; Vita 3 is more tolerant and Vita 5 more sensitive. Both cultivars were submitted to salt stress with 0.1 M NaCl. After 8 days, root and shoot growth from both cultivars was reduced but reduction was more pronounced in Vita 5. Furthermore, leaf area was also reduced in this cultivar. Chlorophyll content and chlorophyll fluorescence parameters were not affected by salt stress, but the specific activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in Vita 3 and increased in Vita 5. The use of immunological techniques also revealed that the Rubisco content from Vita 3 decreased while that of Vita 5 increased.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rubisco; Photosynthesis; Salt stress; Vigna unguiculata. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000200003 |
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| Vitória,Angela P.; Lage-Pinto,Frederico; Campaneli,Leonardo B.; Almeida,Marcelo G.; Souza,Cristina M. M.; Rezende,Carlos E.; Azevedo,Ricardo A.; Oliveira,Jurandi G.. |
| The ecophysiological adaptations of water hyacinth (metal hyperaccumulator) under adverse environmental conditions are not yet clearly elucidated. This work evaluated photosynthetic pigments and chlorophyll a fluorescence in water hyacinth plants sampled in different regions (upper, middle and lower) of Paraíba do Sul river (PSR) and Imbé river, Brazil. Additionally Mn, Fe, Zn, Cu, Cr, Pb and Ni were quantified on the shoots and roots. Roots were the preferential site of metal accumulation. Cromium was not detected in the shoots. Iron and Mn were the elements detected in higher concentrations in all samples. Zinc and Cu were detected in higher concentrations in roots of plants from middle and upper PSR, sites of higher anthropogenic activity. The highest... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pollution; Paraíba do Sul river; Energy dissipation; Photosynthetic pigments; Nonphotochemical quenchings. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202010000100006 |
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| Registros recuperados: 360 | |
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