The Role of Arbuscular Mycorrhiza in the Growth and Development of Plants in the Family Gentianaceae

Arbuscular mycorrhiza (AM) is an ancient symbiosis between land plants and those fungi from the Phylum Glomeromycota. It is estimated to occur in a large majority of plant species, including plants from the family Gentianaceae. Arbuscular mycorrhizal fungi (AMF) colonize plant roots and in exchange for carbohydrates, they contribute to plant mineral nutrient uptake, increased water absorption , tolerance to pathogens, drought, high soil temperatures, toxic heavy metals, extremes in pH and transplant shock. AMF were also reported to have a decisive influence on plant diversity and community productivity. A large plant–fungal network may be established, because more than one plant can be colonized by the same fungal “individual” and each plant may host several fungal species. Non-photosynthetic plants, known as mycoheterotrophs, may parasitize their green neighboring plants by taking up carbohydrates from the shared fungal network. This chapter summarizes research on mycorrhiza and gentians published to date. In brief, all gentians investigated were colonized by AMF and this colonization always had a specific morphology. AMF may play an important role in the life cycle of gentians. For example, several lineages of achlorophyllous mycoheterotrophic gentians showed greatest host specificity known so far in AM. The role of AMF in the growth and development of Gentianaceae is discussed in detail.