| The occurrence of foliar endophytes in the Amazonian palm Euterpe oleracea Mart. was investigated during January and September of 1989 and 1990. Endophytic fungi were isolated from leaflets of ten 6- to 18-month-old seedlings, and of ten 5- to 20-year-old trees located at the Combu Island, a river-island located in the Brazilian Amazon estuary near Belem. Endophytic colonization frequencies were positively correlated with leaf age, plant developmental stages, and subsite. Mature leaves showed higher fungal colonization than the young ones; seedlings were more intensely colonized than trees. Community ordination analysis (MDS) has shown that trees and seedlings located at different subsites were colonized by distinct endophytic communities.;Fifty-seven endophytic species and six familial taxa were identified, Xylaria cubensis and Letendraea sp. were the most dominant colonizers. The endophytic fungi isolated could be generally distinguished by two categories, one representing those taxa that have been primarily referred to as saprophytes, and another category comprising species that have been previously recorded as pathogens in taxonomically close related host plants. Some of the fungi isolated herein represent new species, viz. Idriella amazonica, Idriella asaicola, Idriella euterpes, and Letendraea sp.;Eighty-one isolates representing thirteen species of Xylaria were examined for isozyme variation using starch gel electrophoresis of initially twenty-one enzymes. Five enzymes were selected which represented the most clear resolution. Results from the isozyme analysis revealed a high degree of intra- and interspecific diversity among the thirteen Xylaria species.;A combination of biochemical and cultural data were used to characterize thirty-five endophytic isolates of Xylaria cubensis complex, and then subjected to numerical analysis. In addition, vegetative compatibility group analysis were carried out with the same 35 isolates of X. cubensis in order to assess genetically different (vegetatively incompatible) individuals colonizing the same and different leaves. All pairings of an isolate with itself were compatible. However, several strains were vegetatively incompatible with all other strains, showing that different populations of Xylaria cubensis are present in a single tree. |
