Root fungal associations in some non-orchidaceous vascular lithophytes

ABSTRACT

Plant roots in natural ecosystems are colonized by a diverse group of fungi among which the most common and widespread are arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungi. Though AM and DSE fungal associations are well reported for terricolous plant species, they are rather poorly known for lithophytic plant species. In this study, we examined AM and DSE fungal association in 72 non-orchidaceous vascular plant species growing as lithophytes in Siruvani Hills, Western Ghats of Tamilnadu, India. Sixty-nine plant species had AM and 58 species had DSE fungal associations. To our knowledge, we report AM fungal association in 42 and DSE fungal association in 53 plant species for the first time. There were significant differences in total root length colonization and root length colonized by different AM and DSE fungal structures among plant species. In contrast, the differences in AM and DSE fungal colonization among plants in various life-forms and lifecycles were not significant. AM morphology reported for the first time in 56 plant species was dominated by intermediate type AM morphology. A significant negative relationship existed between total root length colonized by AM and DSE fungi. These results clearly suggest that AM and DSE fungal associations are widespread in lithophytes.

Keywords
arbuscular mycorrhizal fungi; dark septate endophyte fungi; life cycle; life-forms; microsclerotia