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Abstract(s)
A oliveira (Olea europaea L.) é uma cultura com grande importância para a bacia do mediterrâneo e cultivada há séculos por fazer parte da dieta dos povos mediterrânicos. Em Portugal essa cultura desempenha grande papel socioeconómico e cultural com maior enfoque nas regiões interior do país, como é o caso da região de Trás-os-Montes, onde os olivais tradicionais são cultivados em regime de sequeiro. Nos últimos anos, estas plantas têm sofrido com as constantes alterações climáticas. As chuvas não acontecem mais de forma regular, a temperatura média da região tem apresentado aumentos significativos, ocasionando problemas na produtividade. Nesse contexto o presente trabalho teve por objetivo avaliar a eficácia de alguns produtos disponíveis no mercado que visam minimizar os efeitos causados pelas alterações climáticas. Para tal, foram avaliados 4 produtos bioestimulantes à base de algas em oliveiras da cv. Cobrançosa. Foi feito o acompanhamento de campo desde maio a outubro para avaliar qual o efeito na evolução dos estados fenológicos, no crescimento na floração e vingamento. Em laboratório foi avaliada a biometria e composição das folhas no que respeita às clorofilas, carotenoides e atividade antioxidante medida pelos métodos de DPPH, teor de fenóis totais e poder redutor. Os resultados obtidos mostram que a aplicação de bioestimulantes promove o atraso na fenologia e um efeito positivo no crescimento da planta. Relativamente à biometria das folhas, verificou-se diferenças significativas com a aplicação dos bioestimulantes. Em relação ao teor de clorofilas e carotenoides verificou-se que os bioestimulantes não influenciam na sua composição variando o teor de clorofilas entre 14,96 μg/mL e 18,83 μg/mL e os carotenóides de 0,81 μg/mL e 1,16 μg/mL. Para o efeito bloqueador de radicais livres de DPPH após a 2ª aplicação dos produtos a variação obtida dentre os tratamentos foram entre 45,10-53,17% sendo o controlo o tratamento com mais atividade. Nos fenóis totais o T4 é aquele que se distingue com um teor de 60,27 mg ácido Gal/g de amostra. Na avaliação do poder redutor verificou-se uma diminuição nos valores. Estes resultados são ainda preliminares sendo necessário mais anos de estudo para perceber melhor a influencia dos bioestimulantes na planta.
The olive tree (Olea europaea L.) is a crop of great importance for the Mediterranean basin and has been cultivated for centuries, once it is part of the diet of the Mediterranean people. In Portugal, this crop plays a great socioeconomic and cultural role, with a greater focus on the interior regions of the country, as is the case of the Trás-os-Montes, where traditional olive groves are dry-farmed. In recent years, these plants have suffered from constant climate change. The rains no longer happen on a regular basis, and the average temperature in the region has shown a significant raise, causing problems in productivity. In this context, the present work aimed to evaluate the effectiveness of some products available on the market that aim to minimize the effects caused by climate change. For this, 4 olive trees of cv. Cobrançosa seaweed-based biostimulants were evaluated. Field monitoring was carried out from May to October to assess the effect on the evolution of phenological stages, growth, flowering and flourishing. In the laboratory, the biometry and composition of the leaves were evaluated in regard to chlorophylls, carotenoids, and antioxidant activity measured by DPPH methods, total phenol content, and reducing power. The results obtained show that the application of biostimulants promotes delay in phenology and a positive effect on plant growth. In regard to the biometry of the leaves, there were significant differences with the application of biostimulants. Regarding the content of chlorophylls and carotenoids, it was found that biostimulants do not influence their composition, varying the chlorophyll content between 14.96 μg/mL and 18.83 μg/mL and carotenoids from 0.81 μg/mL and 1 .16 μg/ mL. For the blocking effect of DPPH free radicals after the 2nd application of the products, the variation obtained between treatments was between 45.10-53.17%, controlling the treatment with more activity. In the total phenols, T4 is the one that stands out with a content of 60.27 mg acid Gal/g of the sample. In the evaluation of the reducing power, a decrease in the values was verified. These results are still preliminary and more years of study are needed better to understand the influence of biostimulants on the plant.
The olive tree (Olea europaea L.) is a crop of great importance for the Mediterranean basin and has been cultivated for centuries, once it is part of the diet of the Mediterranean people. In Portugal, this crop plays a great socioeconomic and cultural role, with a greater focus on the interior regions of the country, as is the case of the Trás-os-Montes, where traditional olive groves are dry-farmed. In recent years, these plants have suffered from constant climate change. The rains no longer happen on a regular basis, and the average temperature in the region has shown a significant raise, causing problems in productivity. In this context, the present work aimed to evaluate the effectiveness of some products available on the market that aim to minimize the effects caused by climate change. For this, 4 olive trees of cv. Cobrançosa seaweed-based biostimulants were evaluated. Field monitoring was carried out from May to October to assess the effect on the evolution of phenological stages, growth, flowering and flourishing. In the laboratory, the biometry and composition of the leaves were evaluated in regard to chlorophylls, carotenoids, and antioxidant activity measured by DPPH methods, total phenol content, and reducing power. The results obtained show that the application of biostimulants promotes delay in phenology and a positive effect on plant growth. In regard to the biometry of the leaves, there were significant differences with the application of biostimulants. Regarding the content of chlorophylls and carotenoids, it was found that biostimulants do not influence their composition, varying the chlorophyll content between 14.96 μg/mL and 18.83 μg/mL and carotenoids from 0.81 μg/mL and 1 .16 μg/ mL. For the blocking effect of DPPH free radicals after the 2nd application of the products, the variation obtained between treatments was between 45.10-53.17%, controlling the treatment with more activity. In the total phenols, T4 is the one that stands out with a content of 60.27 mg acid Gal/g of the sample. In the evaluation of the reducing power, a decrease in the values was verified. These results are still preliminary and more years of study are needed better to understand the influence of biostimulants on the plant.
Description
Mestrado de dupla diplomação com a UTFPR, Universidade Tecnológica Federal do Paraná
Keywords
Bioestimulantes Cultura Aplicação Antioxidante Fenóis totais