Phosphorus sources in the growth and quality of arabica coffee seedlings produced in tubes / Fontes de fósforo no crescimento e qualidade de mudas de café arábica produzidas em tubetes

The objective of this study was to evaluate the growth and quality of arabica coffee seedlings produced in tubes under different sources of phosphorus (P). The experiment was conducted in a greenhouse in a randomized block design with ten treatments (control, Osmocote®, three doses of pelleted organomineral, three doses of mashed organomineral, MAP, coated MAP) and four replications, three plants per plot. The dose of organomineral, MAP, and MAP coated was based on the recommendation of P2O5for the formation of coffee seedlings.For Osmocote®, the manufacturer's recommendation was used depending on the amount, in dm³, of substrate. After 180 days of transplanting, the growth characteristics of the plants (leaf dry matter, stem, and roots) were evaluated, and the aerial part and root system ratio and Dickson's quality index were calculated, as well as regression equations were adjusted for the evaluated parameters. For the growth and quality of seedlings, it was observed that in fertilizations with pelleted and branched organomineral, coated MAP and Osmocote®, the highest averages were obtained for the contents of dry matter, height, diameter of the collection and quality indexes, when compared to the other sources of P2O5.The dose that provides the maximum growth and quality of coffee seedlings for the treatments with organomineral was calculated, this being equal to 6 g/dm³ of P2O5for bran and pelleted organomineral. According to the results, the sources that promoted the formation of a vigorous seedling, with an adequate supply of nutrients and a good quality standard are pelleted organonineral fertilization and MAP, reducing the risk of losses and consequently the need to discard the seedlings in the nursery.(AU)

O objetivo deste estudo foi avaliar o crescimento e a qualidade de mudas de café arábica produzidas em tubetes sob diferentes fontes de fósforo(P). O experimento foi conduzido em casa de vegetação em delineamento de blocos casualizados com dez tratamentos(controle, Osmocote®, três doses de organomineral peletizado, três doses de organomineral farelado, MAP, MAP revestido)e quatrorepetições, três plantas por parcela. A dose de organomineral, MAP e MAP revestidofoi baseada na recomendação de P2O5para a formação de mudas de café. Para Osmocote®, foi utilizada a recomendação do fabricante emfunção da quantidade, em dm³, de substrato. Após 180 dias do transplante, foram avaliadas as características de crescimento das plantas (matéria seca de folhas, caule e raízes), calculadas a razão parte aérea e sistema radicular e o índice de qualidade de Dickson, bem como ajustadas equações de regressão para os parâmetros avaliados. Para o crescimento e qualidade das mudas, observou-se que nas adubações com organomineral peletizado e farelado, MAP revestido e Osmocote®, as maiores médias para os teores de matéria seca, altura, diâmetro da coletae índices de qualidade, quando comparados as outras fontes de P2O5.Foi possível identificara dose que proporciona o máximo crescimento e qualidade de mudas de café para os tratamentos com organomineral, sendo esta igual a 6 g/dm³ de P2O5para o organomineral farelado e peletizado. De acordo com os resultados, as fontes que promoveram a formação de uma muda vigorosa, com aporte adequado de nutrientes e um bom padrão de qualidade são a adubação organomineral peletizada e MAP, reduzindo o risco de perdas e consequentemente a necessidade de descarte das mudas no viveiro.(AU)

Hormesis with glyphosate depends on coffee growth stage.

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application.

Cafeína: la droga intelectual que estimula al mundo / Caffeine intellectual drug that stimulates the world

La cafeína es la droga estimulante más aceptada socialmente y a su vez, la menos perjudicial. La cafeína es la droga más popular del mundo. Se ha visto que la promueven en Groenlandia, al pie de la capa de hielos eternos; en el extremo meridional de América del Sur, allí donde las aguas del Cabo de los Hornos azotan los roqueros costeños. La usan los nómadas del desierto del Sinaí y los remotos aldeanos del Tíbet y de la China. En la ex Unión Soviética se consumían cada año centenares de millones de litros que la contienen. La encontramos en grandes cartelones por toda América del Norte, de uno a otro océano, si caminamos por las calles de cualquier ciudad europea, no podemos escapar de su aromática presencia. Es la cafeína, que se encuentra en el café, el té, el mate, el cacao, el guaraná, y en un amplio espectro de bebidas con base de cola. La cafeína, es una sustancia presente en numerosos elementos de la dieta diaria, existen opiniones encontradas con respecto a su uso, ya que muchos de sus efectos son valiosos para la vida diaria. Pero también puede producir efectos nocivos si se la usa en dosis excesivas, como ôdependenciaö aunque con un síndrome de abstinencia mucho más, benigno que en otro caso. Sus síntomas son dolor de cabeza, irritabilidad y somnolencia. En general, las personas recurren a la cafeína para poder obtener estimulación, ya que disminuye el cansancio y la fatiga. Se comporta como un estimulante del sistema nervioso central, ayudando a la memoria, facilitando la asociación de ideas y mejorando la percepción sensoria, la cafeína en su justa medida permite incrementar la atención y facilita el proceso bioquímico que se desarrolla durante la formación de la memoria en el cerebro. La cafeína se encuentra en semillas como el café, el cacao, la guaraná, o en hojas como el té y la yerba mate.(AU)

ABSTRACT : Caffeine is a stimulant drug more socially acceptable and in turn, the less damaging. Caffeine is the worlds most popular drug. It has been promoting it in Greenland, at the foot of the permafrost layer, at the southern tip of South America, where the waters of Cape Horn hit coastal rockers. The used by nomads in the Sinai desert and remote village in Tibet and China. In the former Soviet Union were consumed each year hundreds of millions of liters that contain it. It is found in large billboards throughout North America, from one ocean to the other, if we walk through the streets of any European city, we cannot escape its aromatic presence. Is caffeine, found in coffee, tea, mate, cocoa, guarana, and a broad spectrum of cola-based drinks. Caffeine is a substance found in many elements of the daily diet, there are conflicting opinions regarding its use, as many of its effects are valuable life skills. But it can also have harmful effects if used in excessive doses, as "dependency" but with a lot more withdrawal, otherwise benign. Symptoms include headache, irritability and drowsiness. In general, people turn to caffeine stimulation to obtain, since it reduces tiredness and fatigue. It behaves like a central nervous system stimulant, helping memory, facilitate the association of ideas and improving sensory perception, caffeine in perspective can increase attention and facilitates the biochemical process that develops during memory formation in the brain. Caffeine is found in seeds such as coffee, cocoa, guarana, or leaves as tea and yerba mate.(AU)

A role for ferritin in the antioxidant system in coffee cell cultures.

Iron (Fe) is an essential nutrient for plants, but it can generate oxidative stress at high concentrations. In this study, Coffea arabica L. cell suspension cultures were exposed to excess Fe (60 and 240 µM) to investigate changes in the gene expression of ferritin and antioxidant enzymes. Iron content accumulated during cell growth, and Western blot analysis showed an increase of ferritin in cells treated with Fe. The expression of two ferritin genes retrieved from the Brazilian coffee EST database was studied. CaFER1, but not CaFER2, transcripts were induced by Fe exposure. Phylogenetic analysis revealed that CaFER1 is not similar to CaFER2 or to any ferritin that has been characterised in detail. The increase in ferritin gene expression was accompanied by an increase in the activity of antioxidant enzymes. Superoxide dismutase, guaiacol peroxidase, catalase, and glutathione reductase activities increased in cells grown in the presence of excess Fe, especially at 60 µM, while the activity of glutathione S-transferase decreased. These data suggest that Fe induces oxidative stress in coffee cell suspension cultures and that ferritin participates in the antioxidant system to protect cells against oxidative damage. Thus, cellular Fe concentrations must be finely regulated to avoid cellular damage most likely caused by increased oxidative stress induced by Fe. However, transcriptional analyses indicate that ferritin genes are differentially controlled, as only CaFER1 expression was responsive to Fe treatment.

Efeito de fungicidas triazóis sobre o controle da cercosporiose em mudas de cafeeiro / Effectiveness of triazole fungicides for the control of brown eye spot on coffee seedlings

Fungicidas do grupo dos triazóis e suas misturas com inseticidas são convencionalmente empregados para o controle da ferrugem e do bicho mineiro na cultura do cafeeiro. Neste estudo avaliou-se o efeito desses produtos sobre o controle da cercosporiose, causada por Cercospora coffeicola, outra importante doença do cafeeiro. Três experimentos foram realizados em casa de vegetação com mudas de cafeeiro da cultivar Mundo Novo IAC 501, sendo os produtos aplicados na parte aérea e no substrato. Os produtos aplicados na parte aérea foram: epoxiconazol, epoxiconazol + piraclostrobina, tetraconazol, ciproconazol, oxicloreto de cobre, azoxistrobina e carbendazim e no substrato: ciproconazol + tiametoxam, triadimenol + dissulfotom e triadimenol. Testemunhas sem tratamento químico também foram incluídas nos três experimentos. As mudas foram inoculadas com suspensões preparadas com cinco isolados de C. coffeicola (3-4 conídios/mL). A incidência e a severidade da doença foram avaliadas de 20 até 56 dias após as inoculações. Com exceção do oxicloreto de cobre, todos os demais tratamentos foram eficientes no controle da cercosporiose. Os triazóis, com exceção do tetraconazol, apresentaram sintomas reversíveis de fitotoxicidade. Os produtos: ciproconazol + tiametoxam, epoxiconazol + piraclostrobina e carbendazim tiveram os maiores efeitos residuais, e mantiveram o controle da doença por até 56 dias após sua aplica ção. Os triazóis utilizados para o controle da ferrugem também são eficientes para o controle da cercosporiose do cafeeiro.

Triazole fungicides and their mixtures with insecticides are usually employed for the control of coffee rust and leaf miner in coffee crops. In this study these chemicals were evaluated for the control of brown eye spot, caused by Cercospora coffeicola, another important disease of this crop. Three experiments were carried out in a greenhouse with coffee seedlings of the cultivar Mundo Novo IAC 501. The fungicides epoxiconazole, epoxiconazole + pyraclostrobin, tetraconazole, ciproconazole, copper oxychloride, azoxystrobin and carbendazim were applied to the leaves of coffee seedlings, and ciproconazole + tiametoxam, triadimenol + dissulfotom, and triadimenol were applied to the seedlings substrate. Controls were also included in all experiments. The seedlings were inoculated with suspensions prepared with a mixture of five C. coffeicola isolates (3-4 conidia/mL). The incidence and severity of the disease were evaluated 20 to 56 days after the inoculations. With the exception of copper oxychloride, all products were efficient for the control of brown eye spot. The triazoles, with the exception of tetraconazole, showed reversible phytotoxic effects. Ciproconazole + tiametoxam, epoxiconazole + pyraclostrobin and carbendazim had the highest residual effects and maintained small levels of the disease until 56 days after their application. The triazoles used for the control of coffee rust are also effective for the control of brown eye spot.

Photosynthesis and photoprotection in coffee leaves is affected by nitrogen and light availabilities in winter conditions.

Coffee is native to shady environments but often grows better and produces higher yields without shade, though at the expense of high fertilization inputs, particularly nitrogen (N). Potted plants were grown under full sunlight and shade (50%) conditions and were fertilized with nutrient solutions containing either 0 or 23 mM N. Measurements were made in southeastern Brazil during winter conditions, when relatively low night temperatures and high diurnal insolation are common. Overall, the net carbon assimilation rate was quite low, which was associated with diffusive, rather than biochemical, constraints. N deficiency led to decreases in the concentrations of chlorophylls (Chl) and total carotenoids as well as in the Chl/N ratio. These conditions also led to qualitative changes in the carotenoid composition, e.g., increased antheraxanthin (A) and zeaxanthin (Z) pools on a Chl basis, particularly at high light, which was linked to increased thermal dissipation of absorbed light. The variable-to-maximum fluorescence ratio at predawn decreased with increasing A+Z pools and decreased linearly with decreasing N. We showed that this ratio was inadequate for assessing photoinhibition under N limitation. Expressed per unit mass, the activities of superoxide dismutase and glutathione reductase were not altered with the treatments. In contrast, ascorbate peroxidase activity was lower in low N plants, particularly under shade, whereas catalase activity was lower in shaded plants than in sun-grown plants, regardless of the N level. Glutamine synthetase activity was greater in sun-grown plants than in shaded individuals at a given N level and decreased with decreasing N application. Our results suggest that the photoprotective and antioxidant capacity per amount of photons absorbed was up-regulated by a low N supply; nevertheless, this capacity, regardless of the light conditions, was not enough to prevent oxidative damage, as judged from the increases in the H(2)O(2) and malondialdehyde concentrations and electrolyte leakage. We demonstrated that N fertilization could adequately protect the coffee plants against photodamage independently of the anticipated positive effects of N on the photosynthetic capacity.

Changes in some characteristics between the wild and Al-tolerant coffee (Coffea arabica L.) cell line.

An aluminium (Al)-tolerant cell line (LAMt) of coffee (Coffea arabica L.) was obtained from a cell suspension culture and biochemically and molecularly characterized in an MS medium at half ionic strength and low pH. LAMt grew 30% more than the control line (susceptible to Al) in the presence of different concentrations of Al, showed a lower free Al concentration in the medium and had higher phospholipase C specific activity (80%). Membrane integrity of the LAMt was 50% greater than the control line when both were incubated in the presence of different Al concentrations (measured by Evans Blue uptake). Finally, the use of microsatellite primers revealed no difference in the DNA pattern of both cell lines.

[Establisment of a genetic transformation method of coffee (Coffea arabica cv. Catimor) and incorporation of bar gene for ammonium glufosinate resistance]. / Establecimiento de un metodo para la transformacion genetica de cafe (Coffea arabica cv. Catimor) e incorporacion del gen bar que confiere resistencia al herbicida "glufosinato de amonio".

In order to establish a successful method of genetic transformation in Coffea arabica cv. Catimor, different conditions of generation and electroporation were evaluated on different plant tissues. Cell suspension system was improved using one hormone only (BA), obtaining high yields of primary and secondary somatic embryo production. For selection of viable and potentially transformed cells, MTT (1%) method and ammonium glufosinate concentration (1 mg/L in leaf, callus and embryos; and 5 mg/L in cells) were established. Different conditions were evaluated to electroporate different explants (embryogenic callus, vitroplants leaves, globular and torpedo embryos). The highest gus gene expression percentage by explant were found on enzymatic treated tissues at 375 V/cm in callus, and at 625 V/cm in leaves and embryos. Torpedo embryos cultured on liquid medium were the only type of tissue that could regenerate into plants, where secondary somatic embryos were obtained. Those embryos were positive to the gus gene histochemical test and to the gus and bar genes amplification on a PCR reaction.