O uso de substâncias húmicas, aminoácidos e extrato de algas marinhas pode contribuir para o aumento da eficiência fotossintética e metabólica da cana, com reflexos na produtividade e qualidade industrial. Neste trabalho estudou-se o efeito da aplicação foliar de dois produtos comerciais contendo substâncias húmicas, aminoácidos e extrato de algas marinhas, sobre a eficiência nutricional, qualidade industrial e a produtividade de colmos da variedade de cana RB867515. O estudo foi conduzido em dois talhões de 10,0 hectares cada, sendo que um talhão recebeu a aplicação dos produtos e o outro não (testemunha). Os produtos comerciais nas doses de 4,0 litros e 5,0 Kg por hectare foram aplicados sobre a folhagem da rebrota sessenta dias após o corte da cana-planta, ocasião em que as plantas apresentavam altura média de cerca de 80 cm. Dez meses após a aplicação dos produtos foram colhidas dez amostras em cada talhão para avaliar a qualidade industrial e a produção de açúcares. A aplicação dos produtos não influenciou a eficiência nutricional e a qualidade industrial, mas aumentou substancialmente a produtividade de colmos, uma vez que a produtividade média do talhão testemunha foi de 126,8 kg ha-1, enquanto que a do talhão que recebeu a aplicação dos produtos foi de 166,3 kg ha-1.

The use of humic substances, amino acids and marine algae extract can help in increasing sugarcane photosynthetic and metabolic efficiency, with effects on productivity and industrial quality. In this study it was evaluated the effect of the foliar feeding of two commercial products containing humic substances, amino acids and marine algae extract, on the nutritional efficiency, industrial quality, and yield of RB867515 variety sugarcane. It was conducted in two 10.0 ha fields, with the products applied in one field and not in the other (control). The commercial products were applied in 4.0 l and 5.0 kg doses per hectare to re-growth foliage sixty days after cutting the cane-plant when the plants presented an average height of 80 cm. Ten months after applying the products, ten samples were collected from each field to assess the juice quality and sugar production. Applying the products did not influence nutritional efficiency and industrial quality, but did increase stem productivity, since the average for the control field was 126.8 kg ha-1, whereas for the field where the products were applied it was 166.3 kg ha-1.

La producción de caña de azúcar (Saccharum officinarum L.) está influenciada por varios factores abióticos desfavorables, como el estrés salino. La salinidad puede inducir el estrés oxidativo, que causa daño a las biomoléculas y a las estructuras celulares. Sin embargo, estos daños se puede evitar o minimizar por los sistemas de defensa enzimático y no enzimáticos de las plantas. El objetivo del estudio fue determinar el efecto de la prolina exógena en el contenido de Na+ e K+, y la actividad de la catalasa, ascorbato peroxidasa y peroxidasa en dos genotipos de caña de azúcar (RB931011 y RB872552) cultivados in vitro bajo estrés salino. Las plantas se cultivaron durante 20 días en presencia o ausencia de NaCl 100 mM y expuestos a prolina 20 mM durante un periodo de tiempo variable. Los datos fueron sometidos a ANOVA factorial (dos genotipos y cinco tratamientos), y las medias se compararon mediante la prueba de Tukey al 5 % de probabilidad. Bajo estrés salino, ambos genotipos mostraron reducción en la integridad de la membrana, disminución de las proteínas solubles totales y el mantenimiento o incremento en el contenido de prolina endógena. La prolina exógena reduce la acumulación de Na+ en proporción al período de exposición al aminoácido. En ambos genotipos, la actividad de las enzimas antioxidantes se incrementó con la adición de NaCl. En conclusión, el genotipo RB931011 mostró mayor acumulación de prolina y un mayor aumento de la actividad de la catalasa, ascorbato peroxidasa y peroxidasa, lo que indica una mejor tolerancia al estrés salino en comparación con el genotipo RB872552.

Sugarcane (Saccharum officinarum L.) production is influenced by various abiotic stresses, including salt stress. Salinity can induce oxidative stress, which in turn damages biomolecules and cellular structures. However, such damage can be avoided or minimized by the enzymatic and non-enzymatic defense systems of plants. The aim of the study was to determine the effect of exogenous proline on Na+ and K+ content and on the activity of catalase, ascorbate peroxidase and peroxidase in two sugarcane genotypes (RB931011 and RB872552) grown in vitro under salt stress. The plants were grown for 20 days with or without 100 mM NaCl and exposed to 20 mM proline for varying period of time. The data were subjected to ANOVA factorial (two genotypes and five treatments), and the mean values were compared by Tukey test at a 5 % probability. Under salinity stress, both genotypes exhibited membrane integrity reduction, reduced total soluble protein content and unaltered or increased endogenous proline content. Exogenous proline reduced Na+ accumulation in a manner proportional to the exposition period at the amino acid. In both genotypes, antioxidant enzymes activity increased with the addition of NaCl. In conclusion, RB931011 genotype showed higher proline accumulation and increased in activity of the antioxidant enzymes, indicating better salt stress tolerance than in RB872552 genotype.

El objetivo de este trabajo fue inducir la embriogénesis somática directa en segmentos de hojas jóvenes en la variedad de caña de azúcar RB872552, e investigar la correlación de este evento morfogénico con el estrés oxidativo. Se utilizaron dos protocolos de inducción de embriogénesis somática, previamente descritos para caña de azúcar, con distintas suplementaciones en el medio de cultivo y en las condiciones de incubación. Para la conversión de embriones en plantas se utilizó el medio MS sin fitoreguladores. Se realizaron además análisis histológicas y de actividad enzimática antioxidante en tejidos embriogénicos y no embriogénicos. La formación de embriones somáticos ocurrió en 81 % de los explantes, con la combinación de los reguladores de crecimiento 2,4-D (ácido 2,4-diclorofenoxiacético) y BAP (6-bencilaminopurina) e incubación bajo un fotoperiodo de 16 h. Respecto a las enzimas antioxidantes, se observó un incremento en la actividad de peroxidasa y en el contenido de proteínas solubles en los tejidos embriogénicos, mientras que la polifenoloxidasa y la catalasa presentaron valores más bajos de actividad en estos tejidos, en comparación con los no embriogénicos. Se podría inferir que el estrés oxidativo juega un papel importante en la inducción de la embriogénesis somática en caña de azúcar.

The objective of this work was to induce direct somatic embryogenesis from segments of immature leaves of the RB872552 variety of sugarcane and to correlate this morphogenic event with oxidative stress. Two previously described protocols were utilized for the induction of somatic embryogenesis in sugarcane with different supplementations of the culture medium and different incubation conditions. For the conversion of embryos into plants was used MS medium without phytoregulators. Histological analyses and activity of antioxidant enzymes were also conducted for the embryogenic and non-embryogenic tissues. The formation of somatic embryos was obtained in 81 % of the explants with the combination of regulators 2,4-D (2,4-dichlorophenoxyacetic acid)and BAP (6-benzylaminopurine) when incubated under 16 h photoperiod. With regards to the antioxidant enzymes, there was increased activity of peroxidase and an increase in the soluble protein content in embryogenic tissues, whereas lower activities of polyphenol oxidase and catalase appeared in these tissues compared to nonembryogenic tissues. It could be inferred that oxidative stress plays an important role in the induction of somatic embryogenesis in sugarcane.

O experimento foi realizado com o objetivo de avaliar o efeito da redução da PB e da suplementação de rações com aminoácidos industriais sobre o desempenho de poedeiras. Duzentas e setenta poedeiras Lohmann LSL com 26 semanas de idade foram alojadas em densidade de 562 cm²/ave e distribuídas em delineamento inteiramente ao acaso. Foram avaliados os seguintes tratamentos: T1 = dieta controle (DC) com 16,5% PB, 0,80% de lisina (L) e 0,70% de metionina+cistina (MC); T2 = 15,25% PB, 0,73% de L e 0,64% de MC; T3= 14%PB, 0,66% de L e 0,58% de MC; T4 = 15,25% PB com 0,80% de L e 0,64% de MC; T5 = 14% PB com 0,80% de L e 0,58% de MC; T6 = 15,25% PB com 0,73% de L e 0,70% de MC; T7 = 14% PB com 0,66% de L e 0,70 de MC; T8 = 15,25% PB com 0,80% de L e 0,70 de MC; e T9 = 14% PB com 0,80% de L e 0,70% de MC. Cada tratamento foi constituído de cinco repetições de seis aves. As rações continham 2.800 kcal de EM. As suplementações aminoacídicas com 15,25 e 14,00% PB foram realizadas para proporcionar níveis de L, MC ou L+MC semelhantes aos da dieta controle. As aves foram alimentadas com 110 g de ração/dia, receberam água à vontade e foram submetidas a um programa de luz de 17 horas por dia. As características de desempenho foram avaliadas em quatro períodos de 28 dias. A redução da proteína da ração de 16,5 para 14% não alterou o desempenho das aves, mas a suplementação com lisina nas dietas com baixo teor de proteína diminuiu a produção e a massa de ovos e as conversões por massa e por dúzia de ovos em relação à dieta controle.

The effect of decreasing dietary CP and supplementation of lysine and methionine+cystine on the performance of 270 laying hens Lohmann LSL strain was evaluated in this trial. The birds averaging 26 weeks of age were allotted to a stocking rate of 562 cm²/bird as a completely randomized design with five replicate of six birds. The treatments were as follows: T1 = control diet (CD) with 16.5% CP, 0.80% of lysine (L) and 0.70% of methionine+cystine (MC); T2 = 15.25% CP, 0.73% of L and 0.64% of MC; T3 = 14%CP, 0.66% of L and 0.58% of MC; T4 = 15,25% CP with 0.80% of L and 0.64% of MC; T5 = 14% CP with 0.80% of L and 0.58% of MC; T6 = 15,25% CP with 0.73% of L and 0.70% of MC; T7 = 14% CP with 0.66% of L and 0.70 of MC; T8 = 15,25% CP with 0.80% of L and 0.70% of MC and, T9 = 14% CP with 0.80% of L and 0.70% of MC. The diets contained 2,800 kcal of ME. Diets were suppplemented with amino acids at 15.25 and 14.0% of crude protein to show levels of Lys, MC or L+MC similar to control. The birds were fed 110 g of diet/day and water ad libitum and were submitted at a program of light of 17 hours. The variables were evaluated during four periods of 28 days. The decreasing dietary CP from 16.5 to 14% did not affect bird performance, whereas the lysine supplementation of lower protein diet decreased egg production and egg mass and feed:egg mass ratio and feed:egg dozen ratio in relation to control.