Silicon as an attenuator of the toxic effects of aluminum in Schinus terebinthifolius plants.

Aluminum (Al) is highly toxic to plants, since it causes stress and inhibits plant growth. Silicon (Si) is known to mitigate the stress caused by Al in several plant species. Thus, the current study aims to investigate the soothing effects of Si on morphophysiological and photosynthetic variables, and the attributes associated with oxidative stress in Schinus terebinthifolius plants exposed to Al. Treatments have followed a completely randomized design, with three repetitions based on the following Al/Si combinations (in mM): Treatment 1: 0 Al + 0 Si; Treatment 2: 0 Al + 2.5 Si; Treatment 3: 1.85 Al + 0 Si; Treatment 4: 1.85 Al + 2.5 Si; Treatment 5: 3.71 Al + 0 Si; Treatment 6: 3.71 Al + 2.5 Si. Each sampling unit consisted of a tray with 15 plants, totaling forty-five per treatment. Shoot and root morphological variables, photosynthetic variables, photosynthetic pigments, hydrogen peroxide concentration, lipid peroxidation (MDA), guaiacol peroxidase (POD) and superoxide dismutase (SOD) enzymes, and non-enzymatic antioxidant such as Ascorbic acid (AsA) and non-protein thiol (NPSH) concentration were assessed. Root growth inhibition followed by changes in root morphological variables have negatively affected root and shoot biomass production in plants only subjected to Al. However, adding 2.5 mM Si to the treatment has mitigated the toxic effects caused by 1.85 mM of aluminum on S. terebinthifolius plants.

Silicon as an attenuator of drought stress in plants of Oryza sativa L. treated with dietholate / Silício como atenuador de estresse hídrico em plantas de Oryza sativa L. tratadas com dietholate

Abstract Silicon (Si) is an element that can improve the growth and development of rice plants in water-deficient environments because it is an enzymatic stimulant, signaling for production of antioxidant compounds. Therefore, the aim of this study was to examine the relationship between water deficiency and the effect of Si on two rice cultivars whose seeds were treated with dietholate. The experimental design was fully randomized with three replicates, and treatments were organized in a 3x2x2x4 factorial arrangement: three water soil conditions (50% and 100% of soil water retention capacity (WRC) and complete submergence in a water blade of 5.0 cm); two cultivars (IRGA 424 RI and Guri INTA CL); two sources of Si (sodium metasilicate and potassium metasilicate); and four rates of Si (0; 4.0; 8.0 and 16 g L-1). Chlorophyll a and b, leaf area and shoot and root dry weight increased at higher rates of Si under the three soil water regimes. There was an increase in superoxide dismutase and guaiacol peroxidase enzyme activity in the cultivars at higher rates of Si, reducing lipid peroxidation caused by water deficiency. Therefore, Si did indeed attenuate water deficiency stress in rice plants emerging from seeds treated with dietholate.

Resumo O silício (Si) é um elemento que pode proporcionar melhor crescimento e desenvolvimento às plantas de arroz cultivadas em ambientes com deficiência hídrica, por ser um estimulador enzimático, promovendo sinalização para produção de compostos antioxidantes. Assim, o objetivo deste trabalho foi estudar a relação entre deficiência hídrica e o efeito do Si em duas cultivares de arroz tratadas com dietholate. O delineamento experimental utilizado foi inteiramente casualizado, com três repetições e os tratamentos arranjados em esquema fatorial 3x2x2x4, sendo os fatores: três condições hídricas do solo (50%, 100% da capacidade de retenção de água no solo (CRA) e lâmina d'água de 5,0 cm), duas cultivares (IRGA 424 RI e Guri INTA CL), duas fontes de Si (metassilicato de sódio e metassilicato de potássio) e quatro doses de Si (0; 4,0; 8,0 e 16 g L-1). O índice de clorofila a e b, a área foliar e o teor de massa seca da parte aérea e raiz aumentaram com o aumento das doses de Si nas três condições hídricas do solo. Houve um aumento na atividade das enzimas superóxido dismutase e guaiacol peroxidase nas cultivares estudadas à medida que as doses de Si aumentaram, diminuindo a peroxidação de lipídios, causada pela restrição hídrica. Portanto, o Si atenua o estresse por déficit hídrico em plantas de arroz emergentes de sementes tratadas com dietholate.

Silicon as an attenuator of drought stress in plants of Oryza sativa L. treated with dietholate.

Silicon (Si) is an element that can improve the growth and development of rice plants in water-deficient environments because it is an enzymatic stimulant, signaling for production of antioxidant compounds. Therefore, the aim of this study was to examine the relationship between water deficiency and the effect of Si on two rice cultivars whose seeds were treated with dietholate. The experimental design was fully randomized with three replicates, and treatments were organized in a 3x2x2x4 factorial arrangement: three water soil conditions (50% and 100% of soil water retention capacity (WRC) and complete submergence in a water blade of 5.0 cm); two cultivars (IRGA 424 RI and Guri INTA CL); two sources of Si (sodium metasilicate and potassium metasilicate); and four rates of Si (0; 4.0; 8.0 and 16 g L-1). Chlorophyll a and b, leaf area and shoot and root dry weight increased at higher rates of Si under the three soil water regimes. There was an increase in superoxide dismutase and guaiacol peroxidase enzyme activity in the cultivars at higher rates of Si, reducing lipid peroxidation caused by water deficiency. Therefore, Si did indeed attenuate water deficiency stress in rice plants emerging from seeds treated with dietholate.

Silicon as an attenuator of drought stress in plants of Oryza sativa L. treated with dietholate

Abstract Silicon (Si) is an element that can improve the growth and development of rice plants in water-deficient environments because it is an enzymatic stimulant, signaling for production of antioxidant compounds. Therefore, the aim of this study was to examine the relationship between water deficiency and the effect of Si on two rice cultivars whose seeds were treated with dietholate. The experimental design was fully randomized with three replicates, and treatments were organized in a 3x2x2x4 factorial arrangement: three water soil conditions (50% and 100% of soil water retention capacity (WRC) and complete submergence in a water blade of 5.0 cm); two cultivars (IRGA 424 RI and Guri INTA CL); two sources of Si (sodium metasilicate and potassium metasilicate); and four rates of Si (0; 4.0; 8.0 and 16 g L-1). Chlorophyll a and b, leaf area and shoot and root dry weight increased at higher rates of Si under the three soil water regimes. There was an increase in superoxide dismutase and guaiacol peroxidase enzyme activity in the cultivars at higher rates of Si, reducing lipid peroxidation caused by water deficiency. Therefore, Si did indeed attenuate water deficiency stress in rice plants emerging from seeds treated with dietholate.

Resumo O silício (Si) é um elemento que pode proporcionar melhor crescimento e desenvolvimento às plantas de arroz cultivadas em ambientes com deficiência hídrica, por ser um estimulador enzimático, promovendo sinalização para produção de compostos antioxidantes. Assim, o objetivo deste trabalho foi estudar a relação entre deficiência hídrica e o efeito do Si em duas cultivares de arroz tratadas com dietholate. O delineamento experimental utilizado foi inteiramente casualizado, com três repetições e os tratamentos arranjados em esquema fatorial 3x2x2x4, sendo os fatores: três condições hídricas do solo (50%, 100% da capacidade de retenção de água no solo (CRA) e lâmina dágua de 5,0 cm), duas cultivares (IRGA 424 RI e Guri INTA CL), duas fontes de Si (metassilicato de sódio e metassilicato de potássio) e quatro doses de Si (0; 4,0; 8,0 e 16 g L-1). O índice de clorofila a e b, a área foliar e o teor de massa seca da parte aérea e raiz aumentaram com o aumento das doses de Si nas três condições hídricas do solo. Houve um aumento na atividade das enzimas superóxido dismutase e guaiacol peroxidase nas cultivares estudadas à medida que as doses de Si aumentaram, diminuindo a peroxidação de lipídios, causada pela restrição hídrica. Portanto, o Si atenua o estresse por déficit hídrico em plantas de arroz emergentes de sementes tratadas com dietholate.

Produtividade de vinagreira, pimenta rosa e carobinha cultivadas em sucessão a mucuna preta e feijão de porco / Productivity of roselle, Brazilian peppertree, and carobinha grown in succession to black velvet bean and jack bean

RESUMO O uso de adubos verdes e/ou de plantas de cobertura é uma técnica que vem sendo difundida para o cultivo de espécies medicinais, por garantir a sustentabilidade do solo agrícola, ser flexível em seu uso e por melhorar a atividade biológica do solo. O objetivo do trabalho foi avaliar o uso de culturas de cobertura para incrementar a produção de massa de plantas de vinagreira, pimenta rosa e carobinha. Foram avaliadas duas espécies de leguminosas tropicais (mucuna preta e feijão de porco) como cobertura do solo e uma testemunha (sem cultura de cobertura) e três espécies medicinais (vinagreira, pimenta rosa e carobinha). O experimento foi arranjado em esquema de parcelas subdivididas, tendo nas parcelas as coberturas vegetais e nas subparcelas, as plantas medicinais. As plantas para a cobertura vegetal foram propagadas por semeadura direta no local de cultivo, enquanto as medicinais foram transplantadas diretamente entre a palhada da cobertura vegetal. A produção da mucuna preta foi de 8,37 t ha-1 de massa seca e do feijão de porco, de 14,37 t ha-1 de massa seca. O uso das culturas de cobertura contribuiu para uma maior biomassa microbiana do solo. As produções de massas frescas de folhas, caules e frutos de vinagreira e de frutos da pimenta rosa foram maiores quando cultivadas em sucessão às coberturas vegetais do solo, independente da espécie. As produções da carobinha foram semelhantes quando cultivadas em áreas com ou sem a cobertura. Visando à maior produtividade da vinagreira e pimenta rosa, são indicadas as culturas antecessoras feijão de porco e mucuna preta.

ABSTRACT The use of green manure and/or cover crops is a technique that has been widespread for the cultivation of medicinal species, since it ensures the sustainability of agricultural soil, is flexible in its use, and improves biological activity in the soil. The purpose of this study was to evaluate the use of cover crops to increase biomass production of roselle, Brazilian peppertree, and carobinha plants. Two species of tropical legumes (black velvet bean and jack bean) were evaluated as ground covers, and also assessed were one control plot (without cover crops) and three medicinal species (roselle, Brazilian peppertree, and carobinha). The experiment was arranged in a split-plot design, where the plots had cover crops and the subplots contained the medicinal plants. The plants for the cover crop were propagated by direct sowing in the growing site, while the medicinal ones were transplanted directly between the cover crop. The dry mass production of the velvet beans and jack beans were 8.37 t ha-1 and 14.37 t, respectively. The use of cover crops contributed to the increased microbial biomass of the soil. The production of dry mass of leaves, stems, and fruits of roselle and fruits of Brazilian peppertree were higher when grown in succession to the crop cover for the soil, regardless of the species. The production of carobinha was similar when grown in areas with or without the cover. To increase the yield of roselle and Brazilian peppertree, preceding crops of jack bean and black velvet bean are recommended.

Adubação fosfatada associada à cama de frango e sua influência na produtividade e no teor de flavonoides da Marcela (Achyrocline satureioides (Lam. ) DC. ) em duas épocas de colheita / Total biomass and flavonoid contents of Achyrocline satureioides in response to phosphate fertilizer and broiler litter at two successive harvests

RESUMO: Objetivou-se com este trabalho avaliar a produção de massa e o teor de flavonoides de plantas de marcela cultivadas com fósforo e cama de frango e colhidas em duas épocas. Estudou-se a combinação de doses de P2O5 (0, 100, 200 e 300 kg ha-1) na forma de superfosfato triplo, com e sem cama de frango (10 t ha-1), arranjados como fatorial 4x2, no delineamento blocos casualizados, com quatro repetições. Foram feitas duas colheitas das plantas, consideradas como parcelas subdivididas no tempo. A propagação foi indireta, com semeio em bandejas e transplante ao campo. As plantas foram colhidas aos 195 e 223 dias após o transplantio - DAT. A altura máxima das plantas foi de 1,14 m com uso da cama de frango e de 0,97 m sem cama, aos 195 dias após o transplantio. A produção máxima de massa fresca de parte aérea das plantas foi de 30,31 t ha-1 na colheita aos 223 DAT, enquanto a de massa seca foi de 11,38 t ha-1, ambas com o uso de 300 kg ha-1 de P2O5.A massa fresca de inflorescências foi maior (4,08 t ha-1) com adição de cama de frango ao solo e menor (3,49 t ha-1) sem cama de frango; em resposta às doses de fósforo, cresceram linearmente, sendo a máxima de 4,65 t ha-1 com uso de 300 kg ha-1 de P2O5, independente da época de colheita. A massa seca de inflorescências foi máxima de 2,38 t ha-1 com o uso de 300 kg ha-1 P2O5 na colheita aos 223 DAT. A maior produção de massa seca e o maior teor de flavonoides das inflorescências foram obtidos com o cultivo das plantas de marcela em solo com cama de frango (10 t ha-1) e com P2O5 (300 kg ha-1) na colheita aos 223 dias após o transplantio.

ABSTRACT: The aim of this experiment was to evaluate the biomass yield and flavonoid contents of Achyrocline satureioides grown under different levels of phosphate fertilizer in association with broiler litter, during two successive harvests. Four levels of P2O5 (0, 100, 200 and 300 kg ha-1), as triple superphosphate, and two levels of broiler litter (0 and 10 t ha-1) were arranged as a 4x2 factorial design in randomized blocks with four replications. Two harvests of plants, considered as split-plot, were made. Seeds were sown in polystyrene trays then transplanted to the experimental field and harvested at 195 and 223 days after transplanting (DAT). The maximum heights of the plants were 1.14 m under the addition of broiler litter and 0.97 m without it, at 195 days after transplanting. The highest yields of total fresh weight (30.31 ton ha-1) and dry weight (11.38 ton ha-1) were obtained at 223 DAT, both with the concentration of 300 kg ha-1 P2O5. The fresh weight of the inflorescences was greater under the addition of broiler litter (4.08 ton ha-1) than without it (3.49 ton ha-1). The plants grew linearly in response to the use of phosphate, and the maximum yield was 4.65 ton ha-1 under the concentration of 300 kg ha-1 P2O5, regardless of the harvest season. The dry weight of the inflorescences reached maximum yield (2.38 ton ha-1) at 223 DAT, in response to the use of 300 kg ha-1 P2O5. The highest yield of dry weight and the highest contents of flavonoids from the inflorescences were obtained when A. satureioides was grown under the concentration of P2O5 (300 kg ha-1) with the addition of broiler litter (10 ton ha-1) and harvested at 223 DAT.

Influence of poultry litter and plant density on the production and chemical composition of the essential oil of Schinus terebinthifolius Raddi fruits / Influência da cama-de-frango e densidade de plantas na produção e composição química do óleo essencial de frutos de Schinus terebinthifolius Raddi

The aim of this study was to evaluate the production and chemical composition of the essential oil of Brazilian pepper fruits grown in single and double rows using different doses of semi decomposed poultry litter in two evaluation times. The experiment was carried out at the Federal University of Grande Dourados, in the city of Dourados, state o- Mato Grosso do Sul, Brazil, from October 2009 to November 2010. Brazilian pepper plants were grown in single and double rows in soil with incorporated poultry litter at the doses of 0, 5, 10, 15 and 20 t ha-1. Treatments were arranged as a 2 x 5 factorial experiment in a randomized block design with four replications. Fruits were harvested 180 and 390 days after transplant (DAT). There was a significant interaction for fresh weight of fruits and weight of 50 fruits, being the values higher at 180 DAT in the double rows with increasing poultry litter doses. Fruits harvested 390 DAT showed higher diameter compared with those harvested 180 DAT. The number of fruits per bunch was significantly influenced by the doses of poultry litter, presenting a linear increase with increasing doses. The essential oil of the Brazilian pepper fruits obtained by hydrodistillation and analyzed by Gas chromatography - mass spectrometry exhibited predominance of monoterpenes, highlighting α-pinene (20.14%) as the major constituent. The chemical composition of the essential oil was not influenced by the number of plant rows in the plot or by the doses of poultry litter in any evaluation time. Therefore, the cultivation of Brazilian pepper plants is recommended in double rows, with 13.59 t ha-1 of incorporated poultry litter in the soi, and with harvest of 180 DAT for higher fruit production.

O objetivo deste estudo foi avaliar a produção e composição química do óleo essencial de frutos de pimenta-rosa cultivados em fileira simples e dupla com diferentes doses de cama-de-frango semidecomposta em duas épocas de avaliação. O experimento foi realizado na Universidade Federal da Grande Dourados, em Dourados/MS, de outubro de 2009 a novembro de 2010. Plantas de pimenta-rosa foram cultivadas em fileira simples e dupla, em solo com cama-de-frango incorporada nas doses de 0, 5, 10, 15 e 20 t ha-1. Os tratamentos foram arranjados em fatorial 2 x 5, em delineamento de blocos ao acaso com quatro repetições. Os frutos foram colhidos aos 180 e 390 dias após o transplante (DAT). Houve interação significativa para peso fresco de frutos e peso de 50 frutos, sendo os valores maiores aos 180 DAT nas plantas cultivadas em fileira dupla, relacionado com o aumento das doses de cama-de-frango. Os frutos colhidos aos 390 DAT apresentaram maior diâmetro comparado com aqueles coletados aos 180 DAT. O número de frutos por cacho foi influenciado significativamente pelas doses de cama-de-frango, tendo aumento linear em função do aumento das doses. O óleo essencial dos frutos de pimenta-rosa obtido por hidrodestilação e analisado por cromatografia gasosa-espectrometria de massas exibiu predominância de monoterpenos, apresentando como principal constituinte o α-pineno (20,14%). A composição química do óleo essencial não foi influenciada pelo número de fileiras de plantas na parcela, nem pelas doses de cama-de-frango, em nenhuma das épocas de avaliação. Portanto, para maior produção de frutos recomenda-se o cultivo de plantas de pimenta-rosa em fileira dupla e 13.59 t ha-1 de cama-de-frango incorporada ao solo com colheita aos 180 DAT.

Consórcio de manjericão (Ocimum basilicum L. ) e alface sob dois arranjos de plantas / Intercrop of basil (Ocimum basilicum L. ) and lettuce under two plant arrangements

Ocimum basilicum L. (Lamiaceae) é comercialmente utilizada como aromatizante ou condimento preparado com suas folhas verdes e aromáticas, que podem ser usadas frescas ou secas. O objetivo deste trabalho foi avaliar a produção de biomassa de manjericão sob duas ou três fileiras no canteiro, consorciado ou não com alface. O manjericão e a alface foram alocados no campo em experimento conjunto, sendo constituídos cinco tratamentos da seguinte forma: duas fileiras solteiras de manjericão (M2) espaçadas de 0,50 m; três fileiras solteiras de manjericão espaçadas de 0,33 m (M3); quatro fileiras solteiras de alface espaçadas de 0,25 m (A4); duas fileiras solteiras de manjericão consorciadas com quatro fileiras de alface (M2A4) e três fileiras de manjericão consorciada com quatro fileiras de alface (M3A4). O delineamento utilizado foi em blocos casualizados, com oito repetições. As plantas de alface foram colhidas aos 48 dias após o transplantio e as de manjericão, em duas épocas, aos 96 e 113 dias após o transplantio (DAT). O consórcio não influenciou as áreas foliares nem as produções de folhas ou inflorescências do manjericão nem de cabeças comerciais ou não-comerciais da alface. No entanto, quanto ao arranjo de plantas, na segunda época de colheita, as plantas de manjericão cultivadas sob duas fileiras tiveram maior área foliar (2.076,99 cm² planta-1) e maior massa fresca de folhas (5.012,53 kg ha-1). Considerando-se que os valores da Razão de Área Equivalente - RAE na primeira e segunda colheita do manjericão foram maiores que 1,0, conclui-se que o consórcio manjericão com alface é viável. Recomenda-se o arranjo de três fileiras de manjericão alternadas com quatro fileiras de alface, e colheita aos 96 DAT, por ter tido RAE de 2,01.

Ocimum basilicum L. (Lamiaceae) is used commercially as flavoring or seasoning that was prepared with its green and aromatic leaves, which can be used fresh or dried. The aim of this work was to evaluate yield of biomass of basil under two or three rows per plot, intercropped or not with lettuce. Basil and lettuce were planted at field in joined experiment, which established five treatments: two rows of basil in monocrop system (M2) spaced 0.50 m; three rows of basil in monocrop system spaced 0.33 m (M3); four rows of lettuce in monocrop system spaced 0.25 m (A4); two rows of basil in monocrop system and intercropped with four rows of lettuce (M2A4) and three rows of basil intercropped with four rows of lettuce (M3A4). Used design was randomized blocks with eight replications. Lettuce plants were harvested on 48 days after transplanting and basil plants were harvested in two dates, on 96 and on 113 days after transplanting (DAT). Intercrop did not influence on foliar area neither on yields of leaves of inflorescences of basil neither on commercial or non-commercial lettuce heads. Although, regarding plant arrangement, on second harvest date, basil plants that were cultivated under two rows had the greatest foliar area (2,076.99 cm² plant-1) and the greatest fresh masses of leaves (5,012.53 kg ha-1). Considering that the values of Equivalent Area Ration in the first and the second harvest of basil were higher than 1.0. It was concluded that to intercrop basil with lettuce is viable. It is recommended the arrangement of three rows of basil alternated with four rows of lettuce, with harvested at 96 DAT, because it had EAR of 2.01.

Cadmium-induced oxidative stress in two potato cultivars.

A hydroponic experiment was carried out to characterize the oxidative stress responses of two potato cultivars (Solanum tuberosum L. cvs. Asterix and Macaca) to cadmium (Cd). Plantlets were exposed to four Cd levels (0, 50, 100, 150 and 200 microM) for 7 days. Cd concentration was increased in both roots and shoot. Number of sprouts and roots was not decreased, whereas Cd treatment affected the number of nodal segments. Chlorophyll content and ALA-D activity were decreased in both cultivars, whereas carotenoids content was decreased only in Macaca. Cd caused lipid peroxidation in roots and shoot of both cultivars. Protein oxidation was only verified at the highest Cd level. H(2)O(2) content was increased in roots and shoot of Asterix, and apparently, a compensatory response between roots and shoot of Macaca was observed. SOD activity was inhibited in roots of Asterix at all Cd treatments, whereas in Macaca it was only increased at two highest Cd levels. Shoot SOD activity increased in Asterix and decreased in Macaca. Root CAT activity in Asterix decreased at 100 and 150 microM, whereas in Macaca it decreased only at 50 microM. Shoot CAT activity was decreased in Macaca. Root AsA content in Macaca was not affected, whereas in shoot it was reduced at 100 microM and increased at 200 microM. Cd caused increase in NPSH content in roots and shoot. Our results suggest that Cd induces oxidative stress in both potato cultivars and that of the two cultivars, Asterix showed greater sensitivity to Cd levels.