Endorrhizal fungal symbiosis in aroids of the Western Ghats, southern India

Information of dark septate endophyte (DSE), arbuscular mycorrhizal (AM), and fine root endophyte (FRE) fungal symbioses of aroids in the Western Ghats region are very low. Therefore, we assessed the endorrhizal symbiosis in 25 aroid species belonging to 16 genera of Araceae from six different locations of the Western Ghats. The results revealed co-occurrence of the DSE and AM symbiosis in all the examined aroids, and FRE presence in seven aroids (Alocasia ´ amazonica, Alocasia sp., Anthurium andraeanum, Epipremnum aureum, Spathiphyllum sp., Syngonium podophyllum, and Zantedeschia aethiopica). We found variance in root length having AM (inter and intracellular hyphae, arbuscules, vesicles and arbusculate coils) and DSE (melanized septate hyphae, microsclerotia, and moniliform hyphae) fungal structures. Moreover, the AM fungal morphology of Arum-Paris type was widespread, and intermediate type morphology reported for the first time in five aroids. AM fungi colonized the roots of Philodendron xanadu the most, followed by DSE in Caladium bicolor, and FRE in Spathiphyllum sp. AM fungal spores were present in all aroid soils examined. The percentage of root length comprising FRE hyphae was significantly and positively correlated root length with FRE arbuscules, AM fungal spore numbers and total colonization. Our study revealed that, the aroids tend to form associations with various endorrhizal fungi.

Vegetative anatomy of Tabernaemontana alternifolia L. (Apocynaceae) endemic to southern Western Ghats, India

The anatomical description of vegetative parts of Taberenaemontana alternifolia L. belonging to the family Apocynaceae was investigated in the present study. The leaves of T. alternifolia is hypostomatic with paracytic stomata, uniseriate epidermis made up of thin-walled parenchymatous cells covered by thin cuticle on both adaxial and abaxial surfaces. The hypodermis comprises of angular collenchyma cells. Mesophyll is dorsiventral containing silica bodies and vascular bundles are bicollateral. The petiole is flattened adaxially and arch-shaped abaxially with a uniseriate epidermis covered by a thin cuticle. The hypodermis is 7-8 layered angular collenchyma cells consisting of laticifers and parenchymatic, cortical layers consisting of silica bodies and thick-walled fibers and U-shaped bicollateral vascular bundles. Secondary growth in stems is characterized by the formation of periderm and thick-walled fibers in the vascular tissues. Bicollateral vascular bundles are covered by sclerenchymatous patches, parenchymatous cortex and pith consist of fibers, laticifers and silica bodies. The root possess unicellular root hairs, compactly arranged thin-walled uniseriate epidermis, 16-18 layered cortex containing silica bodies and fibers, indistinct endodermis, radially arranged vascular bundles and 14-16 arched xylem. Pitted water-storage cells are present in the conjunctive tissue. Lignin deposition was observed in the root stelar region and pith is absent