ABSTRACT
A interação entre plântulas de cana-de-açúcar e H. seropedicae foi investigada pelo uso da técnica de congelamento por alta pressão seguida de criosubstituição. Observações microscópicas evidenciaram diferenças marcantes entre esta técnica e preparações convencionais, especialmente relacionadas a ultraestrutura da bactéria e às estruturas envolvidas na adesão à superfície da parede celular da planta hospedeira.
ABSTRACT
The interaction between sugar cane plantlets and H. seropedicae was investigated using High Pressure Freezing followed by Freeze Substitution. Microscopical observation showed consistent differences between this approaches when compared with the conventional preparation, specially related to appearance of the bacteria cell and the endophytic attachment to the host cell wall.
A interação entre plântulas de cana-de-açúcar e H. seropedicae foi investigada pelo uso da técnica de congelamento por alta pressão seguida de criosubstituição. Observações microscópicas evidenciaram diferenças marcantes entre esta técnica e preparações convencionais, especialmente relacionadas a ultraestrutura da bactéria e às estruturas envolvidas na adesão à superfície da parede celular da planta hospedeira.
ABSTRACT
Specimens of Chamaesyce thymifolia (Euphorbiaceae) infected and uninfected by Phytomonas sp., a parasite of the Trypanosomatidae family, were anatomically and ultrastructurally analyzed with special emphasis on the laticifer system. C. thymifolia presents branched non-articulated laticifers and was heavily infected by Phytomonas sp. in all collection sites. Infection was often observed in the initial stages inside the vacuole, when the latex particles could be seen. In intermediary stages of laticifer differentiation, Phytomonas sp. were found free in the cytoplasm, inside small vacuoles or in the central vacuole. In differentiated laticifers that had only the plasma membrane, Phytomonas sp. were free in the latex and close to the cell membrane. Infected and uninfected plants showed identical anatomy and ultrastructure and the starch grain numbers in the latex were not reduced in the presence of this flagellate. Biochemical analysis of the latex of infected and uninfected plants presented similar levels of protein, carbohydrate and beta-1,3-glucanase, suggesting that this species is not pathogenic for the host. Besides, all infected plants complete its life cycle. Plants infected with Phytomonas presented occasionally virus like particles and bacteria inside the laticifer tubes.