Plants colonizing volcanic deposits: root adaptations and effects on rhizosphere microorganisms

Background Volcanic activity alters earth surfaces creating environments where new ecosystems can be established. Just some plants are able to colonize this kind of environment. Low availability of nitrogen and phosphorus have been widely considered to restrict plant colonization on volcanic deposits worldwide. Root adaptations such as associations with mycorrhizal fungi, associations with nitrogen-fixing microorganisms, and root structures specialized to exude carboxylates, comprise mechanisms plants use to grow on low nutrient availability conditions, such as volcanic ash or tephra. Scope Most of the studies carried out on volcanic deposit colonizing plants have been focused on aboveground features such as plant survival, growth, and plant-plant interactions. Belowground processes, involving root activity and the rhizosphere, have been less studied. Plants that colonize different volcanically affected areas in the world, the effect on microorganisms associated mainly with the rhizosphere of these plants, microbe-microbe and microbe-plant interactions are reviewed here. Conclusions Plant-to-plant interactions, involving the different kind of roots adaptations, may be complementary to facilitate each other and positively influence the ecosystem recovery of volcanic deposits. At rhizosphere level, particular microbial communities can be recruited with specific beneficial functions (nitrogen-fixing, plant promoting growth, etc.) that improve soil development and plant colonization of volcanic deposits. New aspects such as the ability of mycorrhizal fungi to recruit bacteria able to solubilize phosphorus, and the presence of endophytes and their role in promoting the growth of early plant colonizers of volcanic are also discussed.

Automated summary

Plant colonization on volcanic deposits is limited by the low availability of nitrogen and phosphorus. Belowground processes involving root activity and the rhizosphere have been less studied. Plant-to-plant interactions and specific microbial communities play a crucial role in the ecosystem recovery of volcanic deposits.