Artigos - Periódicos Diversos
URI permanente desta seçãohttps://sbicafe.ufv.br/handle/123456789/14736
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Item Partitioning of nitrate reductase activity in Coffea arabica L. and its relation to carbon assimilation under different irradiance regimes(Brazilian Journal of Plant Physiology, 2007-03-26) Carelli, Maria Luiza C.; Fahl, Joel I.The distribution of in vivo nitrate reductase (EC 1.6.6.1) activity (NRA) between leaves and roots was studied in young coffee plants (Coffea arabica L.) grown in pots with watered sand in a glasshouse and irrigated with nutrient solution. The influence of irradiance regimes on the partitioning of NRA, and its relation with CO2 assimilation, was also evaluated in plants grown under approximately 20, 50 and 100% of full sunlight. Time-course of nitrate accumulation in nitrogen-starved plants showed a similar pattern in leaves and roots after supplying 15 mmol L-1 nitrate, indicating efficient ability of the roots to export nitrate to the shoot. At the same time, NRA was rapidly induced in both tissues. In shoots, NRA partitioning was synchronized among the various leaf pairs. The initial increase in NRA, as each leaf pair emerged, coincided with the optimum NRA values of the next older leaf pair. However, the average shoot NRA remained relatively constant for each sampling date. During the first 23 weeks of vegetative growth, the mean NRA was 32% higher in leaves than in roots. The irradiance regimes influenced the partitioning of NRA between leaves and roots. The NRA leaf /root ratio was 0.72, 1.21 and 1.05, respectively, for plants grown under 20%, 50% and 100% of full sunlight. Leaf NRA was positively correlated with CO2 assimilation, in response to irradiance regimes. Under favorable CO2 assimilation conditions, higher NRA was observed in leaves than in roots, and the contrary trend occurred under limiting CO2 assimilation conditions. Under moderate irradiance regime the leaves were the main site of nitrate reduction, contributing with 70% of the whole plant nitrate assimilation.Item Alterations in leaf anatomy and physiology caused by the red mite (Oligonychus ilicis) in plants of Coffea arabica(Brazilian Journal of Plant Physiology, 2007-06-15) Fahl, Joel I.; Queiroz-Voltan, Rachel B.; Carelli, Maria Luiza C.; Schiavinato, Marlene A.; Prado, Ana K. S.; Souza, Júlio C.Three degrees of red mite infestation (Oligonychus ilicis McGregor) (Acari: Tetranychidae) were evaluated with regard to leaf anatomy, photosynthetic gas exchange and leaf ethylene production, in a commercial crop of approximately 12-year-old trees of Coffea arabica 'Catuaí Vermelho'. As a complementary study, foliar anatomy was also evaluated in a recuperated crop of C. arabica 'Mundo Novo' that had presented a high degree of red mite infestation during the dry period of the prior growing season. The red mite-infested leaves were bronze-coloured, with intensity proportional to the degree of internal damage. On feeding, the red mite introduces its stylet in the adaxial epidermis and, as a result, chloroplasts are destroyed in the feeding area. The number of chlorophyll-free cells in the palisade parenchyma was proportional to the intensity of attack by red mites. The cells of the spongy parenchyma, localized below the feeding areas of the mites, did not show any alterations, having intact chloroplasts, with the exception of some leaves that suffered from intense attack. Net photosynthesis rate declined, but only in leaves under intense red mite attack, due to destruction of chloroplasts in the attacked cells. Nevertheless, transpiration and stomatal conductance were unaffected by red mite. The concentrations of ethylene produced by the leaves were similar regardless of three levels of attack, suggesting that red mite infestation does not lead to leaf abscission. In addition, anatomical studies of 'Mundo Novo' leaves of plants that visually recovered from red mite attack showed that, even with scars present, they continued attached on the plant.Item Ecophysiology of coffee growth and production(Brazilian Journal of Plant Physiology, 2007-12) DaMatta, Fábio M.; Ronchi, Cláudio P.; Maestri, Moacyr; Barros, Raimundo S.After oil, coffee is the most valuable traded commodity worldwide. In this review we highlighted some aspects of coffee growth and development in addition to focusing our attention on recent advances on the (eco)physiology of production in both Coffea arabica and C. canephora, which together account for 99% of the world coffee bean production. This review is organized into sections dealing with (i) climatic factors and environmental requirements, (ii) root and shoot growth, (iii) blossoming synchronisation, fruiting and cup quality, (iv) competition between vegetative and reproductive growth and branch die-back, (v) photosynthesis and crop yield, (vi) physiological components of crop yield, (vii) shading and agroforestry systems, and (viii) high-density plantings.Item Autonomy and network modulation of photosynthesis and water relations of Coffea arabica in the field(Brazilian Journal of Plant Physiology, 2008-08-07) Camargo-Bortolin, Lívia H.G. de; Prado, Carlos H.B. A.; Souza, Gustavo M.; Novaes, PaulaThe degree of connection between leaf gas exchange and leaf water potential, and the autonomy of these variables in relation to meteorological conditions were determined in three cultivars of Coffea arabica during clear and cloudy days. High values of vapor pressure deficit, air temperature and photosynthetic photon flux density resulted in low leaf autonomy during a clear day, irrespective the degree of connection among leaf physiological variables. Tight synchronization between physiological and meteorological variables was considered one important cause of net photosynthesis (P N) decreasing during a clear day. In contrast, diurnal P N was around three times higher on a cloudy day, when all cultivars presented high autonomy. Principal component analyses corroborated autonomy results revealing unambiguous opposition between leaf physiological and meteorological vectors, besides less leaf physiological variability throughout the clear day. Despite these general responses during clear and cloudy days, there were significant differences among studied cultivars. Leaf autonomy was an important reference to evaluate C. arabica under environmental stress and should be taken into account when selecting cultivars under field conditions.Item Seed storage proteins in coffee(Sociedade Brasileira de Fisiologia Vegetal, 2001) BAÚ, SANDRA M. T.; MAZZAFERA, PAULO; SANTORO, LUIZ G.It has been reported that Coffea arabica seeds contain as the main reserve protein, a legumin-like protein, constituted of two subunits, alpha and beta, of approximately 35 and 20 kDa. In this work the seed proteins of several coffee species and varieties were investigated by SDS-PAGE and gel filtration. No differences were observed in the electrophoretic profiles among varieties of C. arabica, however, marked differences were observed among species, or even among individuals of some species. In general, the molecular weight of the subunits alpha and beta accounted for a monomer of 48 to 62 kDa. However, native molecular weight obtained by gel filtration showed that for most of the species there is association of 6 of such proteins, in a hexamer. The most marked difference was observed for C. canephora and C. racemosa. The former clearly showing isoforms of the subunits, and the later showing absence of the beta subunit. The influence of proteases in this observations is discussed.Item Effects of fruiting on the growth of Arabica coffee trees as related to carbohydrate and nitrogen status and to nitrate reductase activity(Sociedade Brasileira de Fisiologia Vegetal, 2001) AMARAL, JOSÉ A.T.; MATTA, FÁBIO M. DA; RENA, ALEMAR B.Active vegetative and reproductive growth in field-grown trees of Coffea arabica L. in Viçosa (20º45’S, 650 m altitude), south-eastern Brazil, occur concurrently. The overall patterns of branch growth and leaf area gain were to a certain extent altered by fruit removal, with growth rates being remarkably greater in de-fruited trees. The content of N-NO3 was not affected by fruiting, whilst that of amino-N was greater in de-fruited than fruiting trees most of the time, but the differences were not large enough to have significantly contributed to the increased growth rates in de-fruited trees. Leaf nitrate reductase activity was greater in plants bearing fruit than in non-bearing ones most of the time; activity was roughly inversely associated with growth. Although the roots contained much more nitrate than the leaves, the root nitrate reductase activity was much lower and not affected by fruiting. Much of the restrictive effects of fruiting on vegetative growth appeared to be associated to starch exhaustion, in addition to the outstanding effect of supra-optimum temperatures per se.Item Biological activities of the fermentation extract of the endophytic fungus Alternaria alternata isolated from Coffea arabica L.(Universidade de São Paulo, Faculdade de Ciências Farmacêuticas, 2009-12) Fernandes, Maurette dos Reis Vieira; Silva, Tales Alexandre Costa e; Pfenning, Ludwig Heinrich; Costa-Neto, Cláudio Miguel da; Heinrich, Tassiela Andréa; Alencar, Severino Matias de; Lima, Marisa Aparecida de; Ikegaki, MasaharuA total of 22 endophytic fungi isolated from coffee (Coffea arabica L.) were cultivated in vitro and their crude extracts tested. The screening was carried out using the agar diffusion method against Staphylococcus aureus, Escherichia coli and Candida albicans. The most effective isolate was Alternaria alternata, and subsequently, its extract was assayed. The total phenolic content was 3.44 μg GAE/mg of the crude extract. For the antibacterial and antifungal activity assays, minimum inhibitory concentrations (MIC) and minimum bactericidal and fungicidal concentrations (MBC and MFC) were determined. The ranges of MIC values were 50-100 μg/mL for S. aureus and 400-800 μg/mL for E. coli. The extract did not show activity in the tested concentrations for C. albicans. The fungal crude extract was assayed for antioxidant activities. Its ability to scavenge DPPH radicals and antioxidant activity by β-carotene/linoleic acid system oxidation was not significant. In addition, antitumor activity was studied using the MTT assay. At a dilution of 400 μg/mL, the extract displayed a cytotoxic activity of approximately 50% towards HeLa cells in vitro. The results indicate that endophytic fungi could be a promising source of bioactive compounds and warrant further study.Item Influence of air temperature on proteinase activity and beverage quality in Coffea arabica(Sociedade Botânica de São Paulo, 2012) Abreu, Hellen Marília Couto de; Nobile, Paula Macedo; Shimizu, Milton Massao; Yamamoto, Paula Yuri; Silva, Emerson Alves; Colombo, Carlos Augusto; Mazzafera, PauloFruits were collected from trees of Coffea arabica cv. Obatã grown at Mococa and Adamantina in São Paulo State, Brazil, which are regions with marked differences in air temperature that produce coffee with distinct qualities. Mococa is a cooler location that produces high-quality coffee, whereas coffee from Adamantina is of lower quality. The amino acid and protein contents, amino acid profile, and proteinase activity and type in endosperm protein extracts were analysed. Proteinase genes were identified, and their expression was assayed. All results indicate that temperature plays a role in controlling proteinase activity in coffee endosperm. Proteinase activity was higher in the endosperm of immature fruits from Adamantina, which was correlated with higher amino acid content, changes in the amino acid profile, and increased gene expression. Cysteine proteinases were the main class of proteinases in the protein extracts. These data suggest that temperature plays an important role in coffee quality by altering nitrogen compound composition.Item Incidence and distribution of filamentous fungi during fermentation, drying and storage of coffee (Coffea arabica L.) beans(Sociedade Brasileira de Microbiologia, 2008-10-02) Silva, Cristina Ferreira; Batista, Luis Roberto; Schwan, Rosane FreitasThe objective of this work was to isolate and characterize filamentous fungi present in different stages of harvest, fermentation, drying and storage of coffee beans processed by natural method. The cherries were hand-picked and then placed on a cement drying platform where they remained until reached 11% of humidity. Microbial counts were found in all samples during fermentation and drying of the coffee beans. Counts of fungi in the coffee cherries collected from the tree (time 0) were around 1.5 x 10³ CFU/g. This number increased slowly during the fermentation and drying reaching values of 2 x 10(5) CFU/g within 22 days of processing. Two hundred and sixty three isolates of filamentous fungi were identified. The distribution of species during fermentation and drying was very varied while there was a predominance of Aspergillus species during storage period. The genera found were Pestalotia (4), Paecelomyces (4), Cladosporium (26), Fusarium (34), Penicillium (81) and Aspergillus (112) and comprised 38 different species.Item Ochratoxigenic fungi associated with green coffee beans (Coffea arabica L.) in conventional and organic cultivation in Brazil(Sociedade Brasileira de Microbiologia, 2013-10-09) Rezende, Elisângela de Fátima; Borges, Josiane Gonçalves; Cirillo, Marcelo Ângelo; Prado, Guilherme; Paiva, Leandro Carlos; Batista, Luís RobertoThe genera Aspergillus comprises species that produce mycotoxins such as aflatoxins, ochratoxins and patulin. These are cosmopolitan species, natural contaminants of agricultural products. In coffee grains, the most important Aspergillus species in terms of the risk of presenting mycotoxins belong to the genera Aspergillus Section Circumdati and Section Nigri. The purpose of this study was to assess the occurrence of isolated ochratoxigenic fungi of coffee grains from organic and conventional cultivation from the South of Minas Gerais, Brazil, as well as to evaluate which farming system presents higher contamination risk by ochratoxin A (OTA) produced by fungi. Thirty samples of coffee grains (Coffea arabica L.) were analysed, being 20 of them of conventional coffee grains and 10 of them organic. The microbiological analysis was done with the Direct Plating Technique in a Dichloran Rose Bengal Chloramphenicol Agar (DRBC) media. The identification was done based on the macro and micro morphological characteristics and on the toxigenic potential with the Plug Agar technique. From the 30 samples analysed, 480 filamentous fungi of the genera Aspergillus of the Circumdati and Nigri Sections were isolated. The ochratoxigenic species identified were: Aspergillus auricoumus, A. ochraceus, A. ostianus, A. niger and A. niger Aggregate. The most frequent species which produces ochratoxin A among the isolated ones was A. ochraceus, corresponding to 89.55%. There was no significant difference regarding the presence of ochratoxigenic A. ochreceus between the conventional and organic cultivation systems, which suggests that the contamination risk is similar for both cultivation systems.
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