The objective of the research was to evaluate responses of nitrogen compounds in relation to the relative water content in noni plant (Morinda citrifolia L.) submitted to water deficit in an interval of 10 days. The experiment was conducted on a greenhouse of the Universidade Federal Rural da Amazônia, Capitão Poço/PA Campus. We used a completely randomized design with two water treatments (control, water deficit) with 16 repetitions. Analysis of variance was applied to the results and compared the means by Tukey test at 5% significance level. The relative water content decreased in plants under water stress. This lack of water provided significant reductions in nitrate concentrations in the roots of 0,74 to 0,13 µmoles of NO 3-/ g.DM and leaves of 0,42 to 0,07 µmoles of NO 3-/ g DM for control and under water deficit plants, respectively. Water deficit also promoted decrease in nitrate reductase activity in leaves and roots, which did not occur with the free ammonium concentrations where they obtained an increase in the roots of 13,7 to 18,5 mmol of NH 4 + / Kg DM and the leaves 4.3 to 8.6 mmol of NH 4 + / Kg DM for the control plants and water deficit, respectively. The total soluble amino acid and proline concentrations increased in roots and leaves. In the case of total soluble protein concentration decreased both roots and leaves. The water stress promoted changes in biochemical parameters in leaves and roots of noni.
A Floresta Nacional de Caxiuanã, localizada no Estado do Pará, ocupa uma área de 324.060 ha, próxima da baía de Caxiuanã, entre os rios Xingu e Amazonas e compreende aproximadamente 70% do município de Portel e 30% do município de Melgaço. O fluxo de energia foi obtido pelo sistema “Eddy Covariance” localizado a 54 metros de altura. Nota-se uma redução de 10,93% comparando os anos de 2015 (2108,1 mm) e 2016 (2367,8 mm), tendo em vista que a redução da precipitação em determinados sítios é uma consequência das mudanças no balanço de energia e água. O albedo médio do dossel na Flona Caxiuanã foi de 8,5% para ambos os anos avaliados. O fechamento do balanço de energia durante o ano de 2015 e 2016 foi da ordem de 74,83% e 69%, valor este abaixo do que é considerado satisfatório (entre 80 e 90%) como encontrado na literatura. A inclusão do termo (S) na equação melhora substancialmente o fechamento do balanço, principalmente para áreas de florestas primárias devido a quantidade de biomassa. Visando a melhora do fechamento, o fluxo de calor latente foi descartado e então estimado como o resíduo da equação Rn – H – G – S, obtendo um fechamento da ordem de 92,05 e 97,26% para 2015 e 2016.Palavras chave: Eddy covariância, balanço de energia, Caxiuanã, fluxo. Balance of radiation, energy and balance closure in a pristine forest in the eastern Amazon A B S T R A C TThe Caxiuanã National Forest, located in the State of Pará, occupies an area of 324,060 ha, close to Caxiuanã Bay, between the Xingu and Amazonas rivers and comprises approximately 70% of the municipality of Portel and 30% of the municipality of Melgaço. The energy flow was obtained by the “Eddy Covariance” system located 54 meters high. A reduction of 10.93% can be seen comparing the years 2015 (2108.1 mm) and 2016 (2367.8 mm), considering that the reduction of precipitation in certain sites is a consequence of changes in the energy balance and water. The average canopy albedo in Flona Caxiuanã was 8.5% for both years evaluated. The closing of the energy balance during the years 2015 and 2016 was of the order of 74.83% and 69%, a value below what is considered satisfactory (between 80 and 90%) as found in the literature. The inclusion of the term (S) in the equation substantially improves the balance sheet closing, mainly for primary forest areas due to the amount of biomass. In order to improve the closure, the latent heat flow was discarded and then estimated as the residue of the Rn - H - G - S equation, obtaining a closure of the order of 92.05 and 97.26% for 2015 and 2016.Key words: Eddy covariance, energy balance, Caxiuanã, flow.
species, colonizer of marginal lands and road margins, which often initiates secondary succession in open areas by the intense germination of their seeds in the soil. Studies on fastgrowing Amazon forest species are very scarce, when it refers to the influence of abiotic factors on an ecophysiology of the species. The experiment was conducted in a greenhouse belong to laboratory of Estudos da Biodiversidade de Plantas Superiores of the Federal Rural University of Amazonia. The experiment was completely randomized in split plot scheme, two times: five and ten days of water suspension, and two water conditions: control and water deficit, with four replications with one plant /pot. The water deficiency condition for ten days negatively affected the growth and indicators of gas exchange (A, gs and E). Adding to the fact that the experiment occurred in a year of extreme climatic anomaly (El Niño), the plants did not resist and perished in the internal conditions of greenhouse. The water deficiency condition altered the growth parameters and the environmental relations of the Tachigali vulgaris species, thus evidencing its low physiological plasticity to this abiotic condition.
Estudos sobre direção e velocidade dos ventos buscam retratar a distribuição espacial e temporal dos ventos nas regiões brasileiras, principalmente nas áreas de grande interesse socioambiental, como as florestas, em especial a floresta Amazônica. O objetivo do trabalho foi caracterizar o escoamento do vento como direção, velocidade e frequência do ar acima de um dossel a 56 m de altura. Um maior conhecimento das características de escoamento sobre a Flona Caxiuanã poderá levar à elaboração de melhores previsões de tempo locais, em relação à ocorrência e intensidade de precipitação, estimativa das temperaturas máximas e mínimas, alertas para ocorrência adversas à sociedade como ventos fortes, irrupção de incêndios e riscos no transporte fluvial. As médias anuais de velocidade foram 1,83 e 1,86 m.s-1, respectivamente. Quanto à classificação, nota-se claramente uma maior frequência em relação a ventos fracos para os anos de 2015 e 2016, com 54,57 e 56,50% respectivamente. Medidas a 64 m de altura no km 67 na Flona Tapajós obtiveram um intervalo de classe variando de 2 a 3 m.s-1 com uma frequência de 52,7%. Quanto à distribuição anual, nota-se claramente o predomínio dos ventos oriundos de NE e L (somados representam 45,45% da captação dos ventos Alísios) para 2015, e de 65,97% para 2016. Durante os anos de 2000 a 2004, os valores mostraram-se iguais estatisticamente p > 0,05, com 1,60 e 1,77 m.s-1 para os períodos chuvoso e seco, respectivamente, e máximas de 1,79 m.s-1. A direção do vento predominantemente foi de NE e L durante os anos avaliados, estando em concordância com a maioria dos estudos situados na região de estudo em detrimento da confluência dos ventos Alísios, embora estando com sua intensidade reduzida em relação a anos ditos normais. A intensidade dos ventos não apresentou diferença estatística quando comparada por sazonalidade, apresentando poucas variações em relação à direção.
Tachigali vulgaris is a pioneer species, colonizing marginal lands and roadsides, often initiates secondary succession in open areas by the intense germination of their seeds in the soil. The main components of the antioxidant defense system can be divided into enzyme found primarily intracellularly (superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione reductase, etc.) and small non-enzymatic molecules that can be divided into soluble in water (ascorbic acid, glutathione and bilirubin) and lipid soluble (α-tocopherol, β-carotene and lycopene). Plants were then separated into leaves and roots, wrapped in aluminum foil and stored in Ultrafreezer at -80 °C. To determine the enzymatic activity and biochemical analyzes, the plant material was first frozen in liquid nitrogen and subsequently lyophilized. The experimental design was completely randomized in a factorial 3 × 2 (three times: zero, five and ten days of water suspension, and two water conditions: control and drought stress), with four repetitions. Analysis of variance was applied to the results and when significant difference, the means were compared using the t test adopting the 5% level of probability through the statistical package (7.7 beta Assistat, 2015). Since they were able to drive quickly the enzymatic antioxidant defense system (SOD, CAT and APX), however, failing to reduce oxidative damage resulting in the death of them.
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