Nitrogen fertilization of fall panicum cultivars (Panicum dichotomiflorum Michx.): biochemical and agronomical aspects

Information on improved fall panicum cultivars and agronomical pratices is scarce because of the relatively small importance of this crop in Brazil. The present study aimed to evaluate levels of nitrogen sidedressing on plant development and biochemical characteristics of two fall panicum cultivars. The experiment was set up under plastic tunnel conditions in Botucatu, São Paulo, Brazil, with plants growing inside asbestos-cement boxes. The experimental design was a randomized block setup and treatments consisted of six levels of nitrogen fertilization (0, 40, 80, 120, 160, and 200 mg L-1) applied at the onset of tillering on two fall panicum cultivars (AL Mogi and AL Tibagi). The application of increasing levels of nitrogen to fall panicum plants increased chlorophyll content, total amino acids, plant dry matter nitrogen content, plant height, tillering and grain yield, and decreased plant dry matter sugar content. The cultivars had similar performances in relation to the evaluated variables, as a response to nitrogen sidedressing.São escassas as informações sobre cultivares melhoradas e técnicas culturais adequadas à cultura do painço. Este experimento objetivou avaliar o efeito da aplicação de níveis de nitrogênio (N) em cobertura no desenvolvimento e nos atributos bioquímicos de duas cultivares de painço. Para tanto, instalou-se um experimento em Botucatu (SP), em caixas de cimento amianto, mantidas em túnel plástico. O delineamento experimental foi em blocos casualizados, em esquema fatorial 2x6, com dois cultivares de painço (AL Mogi e AL Tibagi) e seis níveis de adubação nitrogenada (0, 40, 80, 120, 160 e 200 mg L-1), aplicada em cobertura, no início do perfilhamento. Os dois cultivares utilizados tiveram comportamento semelhante em relação às variáveis avaliadas, em resposta à aplicação de N em cobertura. A aplicação de doses de N na cultura do painço proporcionou incrementos nos teores relativos de clorofila, aminoácidos totais, nitrogênio total e altura das plantas, e redução dos teores de açúcares na matéria seca, até o intervalo entre 120 e 160 mg de N L-1. O perfilhamento e produção de grãos tiveram aumento linear com a aplicação de N. A adubação nitrogenada não afetou a produção de matéria seca

Organic versus conventional fertilization effects on sweet basil (Ocimum basilicum L.) growth in a greenhouse system

Ocimum basilicum L. (sweet basil) is an essential oil producing crop used in culinary and fragrance applications. The objective of this controlled environment study was to evaluate the effects of organic and conventional fertilization (applied at two nitrogen rates, 150 and 250 kg N/ha) on plant growth, essential oil yield and chemical profile, and tissue nutrient accumulation in sweet basil. Overall, basil plants fertilized with organic fertilizer at a rate of 150 kg N/ha accumulated greater concentrations of potassium (K) and manganese (Mn). The highest fresh weight was obtained from the plants grown with conventional fertilizer at a rate of 250 kg N/ha. Treatments did not affect the oil content in dried biomass (0.23–0.36% range), oil yields (11.4–20.7 mg/pot), nor the concentration of eucalyptol, (−)-linalool, bornyl acetate, eugenol, α-trans-bergamotene, germacrene D, ɤ-cadinene and epi-α-cadinol in basil oil. The results from this study demonstrated that organic or conventional fertilizer can alter fresh or dry weight, and nutrient absorption without modifying essential oil composition.Keywords: Essential oil, (-)-Linalool, Eugenol, Nutrients, Nitroge

Dry matter production of common bean with different magnesium levels in nutrient solution

Com o objetivo de avaliar a influência dos níveis de Mg sobre a produção de matéria seca de feijoeiro (Phaseolus vulgaris L. cv. Carioca), empregou-se a solução nutritiva no 2 de Hoagland & Arnon, modificada pela variação da concentração desse mineral, obtendo-se os níveis de 2,4; 24,3; 48,6; 72,9 e 97,2 ppm de Mg. O experimento foi realizado em blocos ao acaso, com três repetições, em esquema fatorial, com cinco níveis de Mg e cinco colheitas, realizadas a intervalos de 14 dias. Os resultados, avaliados em relação aos observados nas plantas submetidas a tratamento com 48,6 ppm de Mg, demonstraram que plantas nutridas com nível de Mg acima desse, não apresentaram alterações pronunciadas, enquanto foram marcantes os aumentos do peso de matéria seca do caule, folhas e total da planta, com a utilização de 2,4 ppm de Mg. Tais resultados sugerem que, para o Phaseolus vulgaris cv. Carioca o nível de 2,4 ppm de Mg seria o ideal quando são considerados os pesos da matéria seca dos órgãos estudados.The effect of Mg levels in nutrient solution upon root, stem, leaf, fruit and total dry matter production of common bean (Phaseolus vulgaris L. cv. Carioca) was studied. Bean plants were grown in Hoagland & Arnon n. 2 solution modified to obtain 2.4, 24.3, 48.6, 72.9 and 97.2 ppm of Mg. The experimental design was a split-plot factorial replicated three times with five Mg levels and five samplings which were done fortnightly. Results were compared with those observed in plants submitted to a nutrient solution with 48.6 ppm of Mg concentration, considered the ideal Mg content. Only a mild prejudicial effect was observed with Mg excessive levels. Stem, leaves and total dry matter were higher when 2.4 ppm were used, suggesting this level as the concentration chosen for the culture of common bean

Magnesium, calcium and potassium in seeds and cotyledons of common bean and its translocation to the young plants

O presente estudo objetivou avaliar os teores de magnésio, cálcio e potássio em sementes e cotilédones do feijoeiro (Phaseolus vulgaris L. cv. Carioca) e a transferência desses minerais dos cotilédones para a planta. Para tanto, plantas de feijão foram cultivadas durante a fase de existência dos cotilédones e irrigadas com água desmineralizada. Foram realizadas três colheitas dos cotilédones das plantas jovens, escolhidas ao acaso de dez repetições, antes da ocorrência de senescência e queda, aos 8, 12 e 15 dias após a germinação das sementes. Em cada colheita, determinaram-se as matérias fresca e seca dos cotilédones e teores de magnésio, cálcio e potássio. Esses parâmetros também foram avaliados em sementes retiradas do mesmo lote. Os resultados demonstraram que o potássio existe nas sementes e cotilédones em maior teor, seguido, em ordem decrescente, pelo magnésio e cálcio. Na 1a colheita dos cotilédones, realizada oito dias após a germinação, 59% de magnésio, 78% de cálcio e 71% de potássio já tinham sido transferidos para as plantas. Na última colheita, realizada 15 dias após germinação, essas porcentagens eram de 73%, 82% e 91%, respectivamente. Desta forma, o mineral menos transferido foi o magnésio, e o mais translocado, o potássio.Magnesium, calcium and potassium concentration in the seeds and cotyledons of Phaseolus vulgaris L. cv. Carioca and its translocation from the cotyledons to the plant were evaluated. For such an evaluation plants were cultivated during the cotyledons phase and were irrigated with deionized water. Three samplings of cotyledons completely randomized were done and replicated ten times, before its senescence and fall, at 8, 12 and 15 days after the germination of the seeds. Fresh and dry matter of the cotyledons and its magnesium, calcium and potassium content were determinated in every sample. These parameters were also determined in the seeds from the same lot. Potassium concentration was higher than magnesium in both seeds and cotyledons. Calcium presented the lesser concentration both in seeds and cotyledons. These minerals were translocated from the seeds and cotyledons to the young plants. Eight days after germination 59% of the magnesium, 78% of the calcium and 71% of the potassium were translocated to the plants. Fifteen days after germination these percentages were respectivaley 73%, 82% and 91%. Thus, magnesium was the less and potassium was the most translocated mineral at the end of the study

Avaliação de substratos na emergência de plântulas de araticum-de-terra-fria (Annona emarginata (Schltdl.) H. Rainer)

Choosing a substrate is the determinant factor for the seedling producer; thus, the aim of this study was to evaluate the effect of different types of substrates on the emergence of araticum-de-terra-fria (Annona emarginata (Schltdl.) H. Rainer) seedlings. The experiment was carried out in a greenhouse and the experimental design was in randomized blocks, with three treatments and five replicates of 72 seeds per plot. The treatments consisted of the following substrates: coconut fiber, vermiculite and Plantmax® Citrus. The number of emerged seedlings was weekly counted for 105 days. Data regarding seedling height were obtained, and the emergence velocity index and mean time, besides total emergence percentage and that over time were calculated. Results from total mean emergence percentage, seedling height, emergence velocity index (EVI), and mean emergence time (MET) were subjected to analysis of variance and means were compared by the Tukey's test at 5% significance. The curves concerning the emergence percentage over time were fit by the logistic growth equation for each treatment and the means of each parameter (A, B, C) were compared by the Duncan's test at 5% significance. The substrates vermiculite led to the highest values of emergence percentage differing from the PlantMax® Citrus, but not of the coconut fiber, however the vermiculite promoted seedling height in a shorter time; therefore, this substrate is recommended for the initial development of araticum-de-terra-fria (Annona emarginata (Schltdl.) H. Rainer) seedlings.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

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http://dx.doi.org/10.5007/2175-7925.2008v21n3p45Este trabalho objetivou avaliar os efeitos da mistura GA3 + AIB + cinetina no desenvolvimento de plântulas de Passifl ora alata Curtis empregando-se análise de crescimento. O experimento foi instalado em casa de vegetação, em blocos casualizados, com seis tratamentos, cinco épocas de colheita e quatro repetições. Os tratamentos consistiram na aplicação foliar de giberelina (GA3), auxina (AIB) e citocinina (cinetina) nas concentrações de 0, 25, 50, 75, 100, 125mL.L-1, realizadas aos 48, 55, 62, 69 e 76 dias após a emergência  das plântulas. A primeira avaliação foi realizada aos 55 dias após a emergência e as demais a intervalos de sete dias. Foram determinadas: área foliar e massa da matéria seca de lâminas foliares e total das plântulas para realização da análise de crescimento, a partir da qual, calculou-se: razão de área foliar (RAF), área foliar específica (AFE), taxa assimilatória líquida (TAL) e taxa de crescimento relativo (TCR). Com o uso do programa ANACRES para avaliar a análise de crescimento foi possível verifi car que o produto influenciou na produtividade vegetal.Effect of plant growth regulators on indices of growth analysis for sweet passion fruit seedlings (Passifl ora alata Curtis). The objective of this work was to investigate the effects of GA3 + IBA + cinetina on the growth of Passifl ora alata Curtis plants through growth analysis. The experiment was carried out by completely randomized block design, with six treatments and four replications. The plant growth regulators,gibberellin (GA3), auxin (IBA) and cytokinin (kinetin), were applied to leaves at concentrations of 0 (control), 25, 50, 75, 100, 125mL.L-1. The applications were performed at 48, 55, 52, 69, and 76 days after the emergence of the plants and the growths were evaluated fi ve times at 7-day intervals. The fi rst evaluations were accomplished 55 days after plant emergence. The leaf area ratio (RAF), specifi c leaf area (AFE), liquid assimilation rate (TCA), and relative growth rate (TCR) were analyzed. The following data were also analyzed for P. alataCurtis plants: leaf area, leaf lamina dry mass and total leaves dry mass. The growth analysis, which employed the ANACRES computer program, indicated that the growth regulators increased plant productivity

Effect of plant growth regulators on indices of growth analysis for sweet passion fruit seedlings (Passiflora alata Curtis)

The objective of this work was to investigate the effects of GA3 + IBA + cinetina on the growth of Passiflora alata Curtis plants through growth analysis. The experiment was carried out by completely randomized block design, with six treatments and four replications. The plant growth regulators, gibberellin (GA3), auxin (IBA) and cytokinin (kinetin), were applied to leaves at concentrations of 0 (control), 25, 50, 75, 100, 125mL.L-1. The applications were performed at 48, 55, 52, 69, and 76 days after the emergence of the plants and the growths were evaluated five times at 7-day intervals. The first evaluations were accomplished 55 days after plant emergence. The leaf area ratio (RAF), specific leaf area (AFE), liquid assimilation rate (TCA), and relative growth rate (TCR) were analyzed. The following data were also analyzed for P. alata Curtis plants: leaf area, leaf lamina dry mass and total leaves dry mass. The growth analysis, which employed the ANACRES computer program, indicated that the growth regulators increased plant productivity