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Brazilian Journal of Plant Physiology, Volume: 23, Número: 1, Publicado: 2011
  • In memoriam to Alvim and Maestri Editorial

    Bressan-Smith, Ricardo; Façanha, Arnoldo Rocha
  • The master and the pupil: two close friends, two great plant physiologists Obituary

    Barros, Raimundo Santos
  • Purification and characterization of cytosolic and cell wall β-galactosidases from Vigna unguiculata stems Research Articles

    Sudério, Fabrício Bonfim; Barbosa, Gislainy Karla da Costa; Gomes-Filho, Enéas; Enéas-Filho, Joaquim

    Resumo em Inglês:

    Three β-galactosidase isoforms, β-gal I and β-gal II (cytosolic) and β-gal III (cell wall-associated), were isolated from stems of Vigna unguiculata (L.) Walp. cv. Pitiúba seedlings. Purification consisted of aμMonia sulfate fractionation followed by chromatography in DEAE-Sephadex and Lactosyl-Sepharose columns. The two cytosolic isoforms showed the same chromatography pattern, which differed from that of β-gal III. Electrophoresis revealed a single band of protein for β-gal II and β-gal III which also expressed β-galactosidase activity in gel. The apparent molecular mass of the β-gal I, II and III was 89, 146 and 124 kDa, respectively. The three isoforms revealed the same optimal pH (4.0) and the same optimal assay temperature (55ºC) for enzyme activity. The three isoforms were stable at temperatures up to 50ºC, and incubation with glucose and galactose expanded their thermal stability as well as inhibited their activities. Galactose was the most effective in promoting these effects and β-gal I and II were competitively inhibited by this sugar. Kinetic analysis using β-PNPG as substrate, revealed K M of 1.69, 1.76 and 1.43 for β-gal I, β-gal II and β-gal III, respectively. The β-gal I was able to hydrolyze all synthetic substrates tested, whereas β-gal II exhibited only β-fucosidase and α-arabinosidase activities, and β-gal III was limited to the α-galactosidase, β-fucosidase and α-arabinosidase activities. These results are consistent with three distinct β-galactosidases exhibiting quite similar kinetic features, but endowed with different functional specificities probably related to their specific roles in the plant cell physiology.
  • Inoculation with mycorrhizal fungi modifies proline metabolism and increases chromium tolerance in pepper plants (Capsicum annuum L.) Research Articles

    Ruscitti, Marcela; Arango, María; Ronco, Marta; Beltrano, José

    Resumo em Inglês:

    In general, heavy metals interfere with several physiological processes and reduce plant growth. Plants naturally establish symbiotic associations with soil microorganisms, such as mycorrhizal fungi. The aim of this research was to determine if inoculation with mycorrhizal fungi increases tolerance to Cr, evidenced by growth and biochemical parameters and the effect on roots membranes in Capsicum annum. Plants were either non-inoculated or inoculated with Glomus mosseae or Glomus intraradices, and grown in the presence of different concentration of Cr (K2Cr2O4) in soil. Pepper plants grown without Cr behaved as mycotrophic species. At the highest concentration (200 μM K2Cr2O4), Cr reduced root colonization by G. mosseae or G. intraradices (to 23 and 20% respectively). Moderate and high concentrations of Cr reduced all growth parameters. The interaction of inoculation and Cr increased leaf chlorophyll and proline content while reduced the leaf protein and root proline content. Carotenoid content was not affected by treatments. High Cr concentrations increased significantly electrolytes leakage in roots, either non-inoculated or inoculated plants. At the highest Cr concentration, inoculated plants had double the biomass of non-inoculated plants. Cr content in roots of inoculated plants was significantly higher than in non-inoculated plants. Chromium accumulation was low in leaves and showed no differences between treatments. Mycorrhization increased pepper plant tolerance to Cr in the soil, modifying proline metabolism to assure a more efficient response.
  • Effect of plant growth regulators on oil yield and biodiesel production of safflower (Carthamus tinctorius L.) Short Communication

    Ullah, Faizan; Bano, Asghari

    Resumo em Inglês:

    The aim of the present investigation was to determine the effect of plant growth regulators viz., kinetin, chlorocholine chloride (CCC) and salicylic acid (SA) on achene yield and oil quality of safflower (Carthamus tinctorius L.) cv. Thori pertaining to biodiesel production. The growth regulators were applied at 10-5M as foliar spray during flowering (140 days after sowing). Kinetin was highly effective in increasing achene yield, 100 achene weight and oil refractive index. Maximum achene oil content was found in CCC treatment. Kinetin and CCC significantly decreased oil acid value, free fatty acid content (% oleic acid) and specific gravity but increased oil pH. Kinetin was highly effective in increasing oleic acid (C18:1) but decreased the content of linoleic acid (C18:2). Oil extracted from achenes of CCC and Kinetin treated plants exhibited maximum (92%) conversion into methyl esters.
  • Physic nut plants present high mycorrhizal dependency under conditions of low phosphate availability Research Articles

    Balota, Elcio Liborio; Machineski, Oswaldo; Viviane Truber, Priscila; Scherer, Alexandra; Souza, Fabio Suano de

    Resumo em Português:

    O pinhão manso (Jatropha curcas L.) é uma planta perene que pode ser encontrada naturalmente em regiões tropicais e subtropicais do Brasil. Seus frutos apresentam 28% de óleo com base no peso seco. Apesar de o pinhão manso apresentar alta adaptabilidade às diversas condições do solo como baixa fertilidade, a correção da acidez do solo e a adição de fertilizantes são fundamentais para a alta produtividade das plantas. Por isto é essencial avaliar o comportamento do pinhão manso em diferentes níveis de P e sua resposta a inoculação dos fungos micorrízicos arbusculares (FMA). O objetivo do trabalho foi o de avaliar o efeito dos fungos micorrízicos arbusculares em mudas de pinhão manso em diferentes doses de P no solo. Foi conduzido um experimento em casa de vegetação, com tratamentos de fungos micorrízicos (Controle, Gigaspora margarita e Glomus clarum) e de adição de P (0, 25, 50, 100, 200 e 400 mg kg solo-1). Houve efeito benéfico significativo dos fungos micorrízicos arbusculares no desenvolvimento vegetativo como: peso da matéria seca da parte aérea e das raízes, altura, diâmetro do caule, número de folhas, área foliar, área foliar por folha e índice de qualidade Dickson, principalmente nas doses menores de P. A relação raiz:parte aérea e relação da área foliar foram influenciadas pela micorrização e pelos teores de P no solo. O pinhão manso apresentou alta dependência micorrízica até a dose de 50 mg kg-1 de P.

    Resumo em Inglês:

    The physic nut (Jatropha curcas L.) is a perennial tree that occurs naturally in the tropical and subtropical regions of Brazil. Fruits of physic nut present an oil content of 28% on a dry weight basis. Although the plant has adapted to diverse soil conditions such as low fertility, the correction of soil acidity and the addition of fertilizer are essential for highly productive plants. Thus, the response of the physic nut to different soil phosphorus levels (P) and arbuscular mycorrhizal fungi (AMF) inoculation must be characterized. Hence, the objective of the present study was to evaluate the response of physic nut seedlings to arbuscular mycorrhizal fungi (AMF) inoculation at different levels of soil P. Experiment was carried out in a greenhouse encompassing AMF treatments (inoculation with Gigaspora margarita or Glomus clarum, and the non inoculated controls), and phosphorus treatments (0, 25, 50, 100, 200 and 400 mg kg-1 added to soil). At low soil P levels, arbuscular mycorrhizal fungi inoculation had a significant positive effect on plant growth, shoot and root dry matter content, plant height, number of leaves, total leaf area, leaf area per leaf and the Dickson quality index. The root:shoot ratio and the leaf area ratio were also affected by mycorrhizal inoculation and the level of P addition. Physic nut plants exhibited high mycorrhizal dependency at soil P additions up to 50 mg kg-1.
  • Differential activation of the enzymatic antioxidant system of Abelmoschus esculentus L. under CdCl2 and HgCl2 exposure Research Articles

    Hameed, Asiya; Qadri, Tabasum N.; Mahmooduzzafar,; Siddiqi, T.O.; Iqbal, M.

    Resumo em Inglês:

    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 adaptations and ultimate survival of this plant species during stress conditions. A reduction of catalase activities was observed on exposure to these metals, which is supposedly due to the inhibition of enzyme synthesis. Root length, shoot length, number of leaves showed an enhancement with 0.05 mM CdCl2 dose then a gradual decline with the increase in concentrations. The results indicate that A. esculentus is tolerant to high concentrations of these metals, a property related to a differential activation of its enzymatic antioxidant system, and also reveal that this species has a higher capacity of Cd absorption.
  • Latex fluids are endowed with insect repellent activity not specifically related to their proteins or volatile substances Research Articles

    Ramos, Márcio V.; Araújo, Eliane S.; Oliveira, Raquel S. B.; Teixeira, Fabiano M.; Pereira, Danielle A.; Cavalheiro, Mariana G.; Souza, Diego P.; Oliveira, Jefferson S.; Freitas, Cleverson D. T. de

    Resumo em Inglês:

    Latex is an endogenous milky fluid synthesized and accumulated under pressure in a network of laticifer cells. In this study, latices from five plant species were examined for deterrent effect on oviposition of two Coleoptera (Bruchidae) pests. The latex from Euphorbia tirucalli, Calotropis procera and Plumeria rubrae exhibited deterrent activity on oviposition of both Callosobruchus maculatusand Zabrotis subfasciatus beetles. The latex from Cryptostegia grandiflora and Himathantus drasticus were less effective to C. maculatus and Z. subfasciatus oviposition, respectively. Eggs laid on latex-treated seeds were not affected.The emergence and the mean time of development and weight of larvae grown in treated seeds were similar to the controls. The deterrent activity of C. procera and P. rubra was dose and time-dependent for Z. subfasciatus rather than to C. maculatus. The deterrent effect was completely eliminated if the whole latices were fractionated in protein fractions, rubber and small metabolites. Exposing insects to crude latices did not alter ovipostion on untreated seeds. These RESULTSsuggest that latices possess deterrent activity on insect oviposition mediated by a repellent effect, but that proteins and volatile substances are probably not involved. The repellent-like activity can be considered as a defensive role played by these fluids that relies on the combined action of their components.
  • Synergistic response of auxin and ethylene on physiology of Jatropha curcas L. Research Articles

    Joshi, Gargi; Shukla, Arvind; Shukla, Alok

    Resumo em Inglês:

    Jatropha curcas L. is a versatile crop since all its plant material is brought to use either as energy source, industrial or medicinal purpose. Several studies are ongoing in different parts of the world to optimize, enhance and exploit the growth, fruiting cycle and different developmental stages of the plant so that the economic yield of the plants can be utilized to the fullest limits. Foliar application of plant growth regulators such as ethrel (an ethylene releasing compound), indole acetic acid (IAA) and naphthalene acetic acid (NAA) at 50, 100 and 150 ppm, was found to influence different morpho-physiological characters in Jatropha curcas L, such as plant height, collar diameter, tree spread, flower initiation, number of inflorescence per plant, number of male and female flowers per inflorescence, and the ratio of male: female flowers per inflorescence. Moreover, the leaves chlorophyll content, Fv/Fm value, nitrate reductase activity and proline content were also affected by synergistic response of auxin and ethylene. As higher the plant growth regulators concentration higher was the synergic effect on the Jatropha curcas L physiology.
  • An outlook on ion signaling and ionome of mycorrhizal symbiosis Mini Review

    Ramos, Alessandro C.; Façanha, Arnoldo R.; Palma, Livia M.; Okorokov, Lev A.; Cruz, Zilma M.A.; Silva, Ary G.; Siqueira, Arthur F.; Bertolazi, Amanda A.; Canton, Gabriela C.; Melo, Juliana; Santos, Wolmen O.; Schimitberger, Vanusa M. B.; Okorokova-Façanha, Anna L.

    Resumo em Português:

    A interação que se desenvolve há mais de 450 milhões de anos, entre a maioria das plantas terrestres e os fungos micorrízicos é uma das mais antigas, conspícuas e ecologicamente importantes simbioses na Terra. Os eventos iniciais na evolução da simbiose micorrízica parecem ter envolvido mudanças genéticas recíprocas nas plantas ancestrais e nos fungos de vida livre. novos dados sobre o mecanismo de ação de moléculas sinalizadoras específicas destas interações, e de como estas influenciam e são influenciadas pelos fluxos de íons nas membranas e oscilações iônicas citoplasmáticas estão ampliando nossa compreensão das bases moleculares do processo de micorrização. esta revisão destaca tópicos sobre o estudo do ionoma e da comunicação iônica da simbiose micorrízica enfocando os sinais envolvidos no desenvolvimento da simbiose. Uma visão geral da simbiose será apresentada refletindo a integração dos dados disponíveis com novas perspectivas para as pesquisa no campo.

    Resumo em Inglês:

    The 450-million-year-old interaction between the majority of land plants and mycorrhizal fungi is one of the most ancient, abundant, and ecologically important symbiosis on earth. The early events in the evolution of mycorrhizal symbioses seem to have involved reciprocal genetic changes in ancestral plants and free-living fungi. new data on the mechanism of action of specific signaling molecules and how it influence and is influenced by the membrane ions fluxes and cytoplasm ion oscillations which integrate the symbiotic ionome are improving our understanding of the molecular bases of the mycorrhization process. This mini-review will highlight topics regarding what is known about the ionome and ionic communication in the arbuscular mycorrhizal symbiosis focusing on the signals involved in the development of symbioses. Here we present an overview integrating the available data with the prospects of the research in the field.
Brazilian Journal of Plant Physiology Centro de Ciências e Tecnologias Agropecuárias, , Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF, 28013-602 - Campos dos Goytacazes, RJ - Brazil, Fax: (+55)-22-2739-7116 - Campos dos Goytacazes - RJ - Brazil
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