Endophytic aquatic hyphomycetes in roots of riparian tree species of two Western Ghat streams

Abstract

Bubble chamber incubation of surface sterilized segments of root bark and xylem of 10 riparian tree species of the Sampaje (475–500 m asl) and VʼBadaga (765–800 m asl) stream reaches of the Western Ghats yielded 20 species of endophytic aquatic hyphomycetes. Anguillospora crassa, A. longissima and Cylindrocarpon sp. were among the top five species in streams. A two-way ANOVA showed significantly higher species richness and counts of conidium in the tree species of Sampaje compared to VʼBadaga (p < 0.001), while two variables were not significantly different between bark and xylem. The total number of species recovered was slightly higher in bark than in xylem (14–19 vs. 13–17 spp.) and the average species richness between tissues did not differ significantly except for one tree species (Madhuca neriifolia: p < 0.05). The release of conidia from bark of only three tree species was significantly higher than from xylem (M. neriifolia and Canarium strictum: p < 0.05; Vateria indica: p < 0.01). Sorensen’s similarity index for bark as well as xylem between tree species was higher in Sampaje stream than in VʼBadaga stream (0.45–0.78 vs. 0.25–0.61). The diversity of aquatic hyphomycetes in bark and xylem was higher in the trees of Sampaje than VʼBadaga (3.1–3.3 vs. 2.7). A cluster analysis of aquatic hyphomycetes in bark and xylem resulted in two groups coinciding with the two streams. The results of this study revealed that assemblage and diversity of endophytic aquatic hyphomycetes in riparian tree roots are high in the mid-altitude Sampaje stream as previously documented for saprotrophic aquatic hyphomycetes.