RESUMOEste trabalho objetivou modelar o crescimento em diâmetro para árvores individuais de Araucaria angustifolia, ocorrentes na Floresta Ombrófila Mista no nordeste do Rio Grande do Sul. Para tanto, foram utilizadas remedições em intervalo de 7 anos de 251 indivíduos de araucária ocorrentes nas parcelas permanentes do Projeto PELD/CNPq. Foi construído um modelo de produção, tendo como variável dependente o diâmetro futuro, utilizando regressão e análise de covariância. Como variáveis independentes, foram utilizadas as características dimensionais e sociológicas dos indivíduos e os índices de concorrência independentes de distância. A variável mais correlacionada com o diâmetro futuro foi o diâmetro atual. Os índices de concorrência apresentaram alta correlação com a variável dependente, representando a pressão competitiva exercida sobre a árvore, mas não foram selecionados no modelo de regressão. Somente o diâmetro atual, multiplicado por um coeficiente, acrescido de um valor constante o qual diferiu de acordo com a posição sociológica do indivíduo, foi eficiente para predizer o diâmetro futuro. Foram construídos três variações do modelo de produção. Esses modelos apresentaram melhores estimativas para indivíduos de Araucaria angustifolia emergentes, no entanto, o seu emprego na prognose de crescimento de árvores individuais deve ser cauteloso por causa da magnitude dos erros de predição que apresentou. Palavras-chave: concorrência; incremento diamétrico; pinheiro-brasileiro. ABSTRACTThis work aims to model the diameter growth for individual trees of Araucaria angustifolia, present in the Mixed Ombrophylous Forest in the northeast of Rio Grande do Sul. Thus, 251 araucaria individuals located on the permanent plots of the Project PELD -CNPq were remeasured after a period of 8 years. A yield model was built, having as dependent variable the future diameter, using regression and analysis of covariance. As independent variables, the dimensional and social characteristics of the individuals and distance independent competition indices were used. The most correlated variable with the future diameter was the current diameter. The competition indices showed high correlation with the dependent variable, representing the competitive pressure exerted on the tree, but they were not selected in the regression model. Only the current diameter, multiplied by a coefficient, plus a constant value which differed according to the sociological position of the individuals was effective to predict the future diameter. Three variations of the production model were built. The models showed better estimates for emerging individuals of

Este trabalho teve como objetivo avaliar diferentes modelos de afilamento do fuste de Pinus taeda para estimar variáveis de interesse ao longo do fuste. Foram avaliadas as funções propostas por Anony, Kozak, Munro, Silva & Sterba, Prodan e o Polinômio de 5° grau. O estudo teve como base dados de cubagem rigorosa de 68 árvores, provenientes de plantios com idade de 25 anos, pertencentes à empresa Florestal Gateados Ltda, localizada no município de Campo Belo do Sul, Santa Catarina (SC), Brasil. A partir das estatísticas coeficiente de determinação ajustado (R²aj), erro padrão das estimativas (Syx), desvio médio, média das diferenças (md) e desvio padrão das diferenças (dpd) foi selecionado o Polinômio do 5° grau para estimar as variáveis ao longo do fuste, como a altura comercial, o volume comercial, os diâmetros e os volumes das 1ª e 2ª toras. Em relação à altura comercial, a equação proveniente do modelo escolhido apresentou resultados sem tendências e com erros oscilando em intervalo pequeno. Em se tratando do volume comercial, pode ser observada certa tendência em subestimativas para as árvores com menores DAP e uma leve tendência para aquelas árvores com maior DAP. Em relação ao diâmetro e ao volume da 1a tora, houve superestimativa dos valores, mas com erros baixos, principalmente para o diâmetro. Para as estimativas do diâmetro e do volume da 2ª tora, os resultados foram melhores do que os encontrados na 1a tora, com leve tendência em subestimar o diâmetro e, praticamente, sem tendência para o volume.

Copper (Cu) can be toxic to vegetables when it is absorbed and accumulated at large concentrations, a fact that increases the risk of excessive addition of this metal to the human food chain. The aims of the current study are (1) to determine the Cu concentrations that have critical toxic effects on beet and cabbage plants, and the potential of these plants to enter the human food chain; as well as (2) to assess the physiological and biochemical responses of representatives of these vegetables grown in nutrient solution presenting increasing Cu concentrations. Beet and cabbage plants were grown for 75 days in pots lled with sand added with nutrient solution presenting six Cu concentrations: 0.00, 0.52, 1.02, 1.52, 2.02 and 2.52 mg Cu L -1 . Dry matter yield and Cu accumulation in different plant organs were evaluated. Photosynthetic pigment contents, lipid peroxidation levels (TBARs), superoxide dismutase (SOD, EC 1.15.1.1) and peroxidase (POD, EC 1.11.1.7) activity, and hydrogen peroxide (H 2 O 2 ) concentrations in leaves were evaluated. Critical Cu concentrations that led to toxicity in plant organs such as beetroot and cabbage head, which are often found in human diets, corresponded to 1.43 mg Cu L -1 and 1.59 mg Cu L -1 , respectively. High Cu concentrations in the nutrient solution have increased Cu concentrations and accumulation in plant tissues. This outcome justi ed the increased POD and SOD enzyme activity in the leaves of beet and cabbage plants, respectively, as well as was the cause of reduced plant growth in both crops. Cabbage plants presented higher tolerance to increased Cu levels in the growing environment than beet plants. However, it is necessary being careful at the time to consume both vegetables, when they are grown in Cu-enriched environments.

Most works on strawberry refer to conventional production systems and in traditional regions, so there is little scientific knowledge for its cultivation in other conditions, such as in the organic production of northwestern RS, Brazil. The objective of this work was to evaluate the productive aspects and physicochemical characteristics of strawberry cultivars grown in an organic production system in the northwest of RS. The experiment was carried out at the Cerro Largo Campus of the Federal University of the Southern Frontier between June 2013 and January 2014. The experimental design was a randomized block design with six blocks composed of three experimental units. Each unit consisted of 20 plants arranged in four interspersed lines, with plants spaced 0.30 m apart. Three strawberry cultivars were compared: Albion, Aromas and San Andreas. Yield variables were determined by mass, number, volume of pseudofruits and production percentage of non-marketable pseudofruits. Quality was determined from soluble solids content (SS), titratable acidity (TA), SS/TA ratio and pH. The cultivars Aromas and Albion were the most adapted to the organic production system under the conditions determined in this work.

No abstract