Estresse oxidativo em clones de seringueira sob ataque de oídio
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Data
2011-09-02
Autores
Gonzalez, Gisely Cristina [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A seringueira [Hevea brasiliensis (Willd. ex Adr. de Juss.) Müell. Arg.] possui a maior capacidade produtiva de látex ao compará-la com outras espécies do mesmo gênero, podendo ser utilizada para reflorestamento, recuperação de áreas degradadas e em sistemas agroflorestais. Porém, a produtividade desta cultura pode ser afetada pela ocorrência de fungos patogênicos, dentre eles o Oidium heveae e causa uma das mais importantes doenças da seringueira, o oídio. No presente trabalho foi estudada a infestação do O. heveae em mudas de três clones de H. brasiliensis: RRIM 600, GT1 e PR255, com o objetivo de determinar algumas alterações bioquímicas relacionadas ao estresse oxidativo e conhecer a correlação destes com a resistência dos clones infectados. O presente experimento foi conduzido em ambiente aberto sob condições fotoperiódicas naturais em setembro de 2010. No início do período experimental as plantas de seringueira foram infectadas através da pulverização de uma solução aquosa contendo O. heveae na concentração de 16 x 104 conídios mL-1. No dia da inoculação e após 48, 96 144 e 192 h foram coletadas amostras foliares para determinação das atividades das enzimas antioxidantes glutationa S-transferase, superóxido dismutase e peroxidase, bem como os indicadores de estresse oxidativo, tais como, lipoperóxidos, pigmentos fotossintéticos, açúcares solúveis e peróxido de hidrogênio. O estresse gerado pelo patógeno não alterou significativamente o teor de lipoperóxidos e os açúcares solúveis totais e redutores. Degradação nos pigmentos fotossintéticos e diminuição nos teores de H2O2 no período de infecção foi observada nos clones de seringueira estudados
The rubber tree [Hevea brasiliensis (Willd. ex Adr. Of Juss.) Muell. Arg.] has the largest production capacity of latex in comparison of other species of the genus and can be used for reforestation, rehabilitation of degraded lands and agroforestry. However, the productivity of this crop may be affected by the occurrence of pathogenic fungi, such as Oidium heveae and causes one of the most important diseases of rubber trees, powdery mildew. In this work was studied the infestation of O. heveae on seedlings of three clones of H. brasiliensis RRIM 600, GT1 and PR255, in order to determine some biochemical changes related to oxidative stress related to resistance of infected clones. This experiment was conducted in open air under natural photoperiodic conditions in September 2010. At the beginning of the trial period the rubber plants were infected by spraying an aqueous solution containing O. heveae at concentration of 16 104 conidia mL-1. On the day of inoculation and after 48, 96 144 and 192 h leaf samples were collected for determination of the activities of antioxidant enzymes glutathione S-transferase, superoxide dismutase and peroxidase, as well as indicators of oxidative stress, such as lipoperoxides, photosynthetic pigments, soluble sugars and hydrogen peroxide. The stress generated by the pathogen did not significantly alter the content of lipoperoxides and total and reduced soluble sugars. Degradation in photosynthetic pigments and decreased the levels of H2O2 in the period of infection was observed in clones of rubber studied. Activity of antioxidant enzymes GST, SOD and POD was higher in clone RRIM600 and was unchanged in the other clones after inoculation by O. heveae. Therefore, the oxidative stress in rubber three clones studied, indicated by the degradation of photosynthetic pigments and low levels of hydrogen peroxide
The rubber tree [Hevea brasiliensis (Willd. ex Adr. Of Juss.) Muell. Arg.] has the largest production capacity of latex in comparison of other species of the genus and can be used for reforestation, rehabilitation of degraded lands and agroforestry. However, the productivity of this crop may be affected by the occurrence of pathogenic fungi, such as Oidium heveae and causes one of the most important diseases of rubber trees, powdery mildew. In this work was studied the infestation of O. heveae on seedlings of three clones of H. brasiliensis RRIM 600, GT1 and PR255, in order to determine some biochemical changes related to oxidative stress related to resistance of infected clones. This experiment was conducted in open air under natural photoperiodic conditions in September 2010. At the beginning of the trial period the rubber plants were infected by spraying an aqueous solution containing O. heveae at concentration of 16 104 conidia mL-1. On the day of inoculation and after 48, 96 144 and 192 h leaf samples were collected for determination of the activities of antioxidant enzymes glutathione S-transferase, superoxide dismutase and peroxidase, as well as indicators of oxidative stress, such as lipoperoxides, photosynthetic pigments, soluble sugars and hydrogen peroxide. The stress generated by the pathogen did not significantly alter the content of lipoperoxides and total and reduced soluble sugars. Degradation in photosynthetic pigments and decreased the levels of H2O2 in the period of infection was observed in clones of rubber studied. Activity of antioxidant enzymes GST, SOD and POD was higher in clone RRIM600 and was unchanged in the other clones after inoculation by O. heveae. Therefore, the oxidative stress in rubber three clones studied, indicated by the degradation of photosynthetic pigments and low levels of hydrogen peroxide
Descrição
Palavras-chave
Oídio, Seringueira, Seringueira - Estresse oxidativo, Antioxidant enzymes, Hevea brasiliensis, Oidium heveae
Como citar
GONZALEZ, Gisely Cristina. Estresse oxidativo em clones de seringueira sob ataque de oídio. 2011. xiv, 90 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2011.