Effects of elevated CO2 on root symbionts mediated by plants.

DÍAZ, S

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 1996 vol. 187 p. 309 - 320

0032-079X

This review examines the effects of elevated [CO2] on plant symbioses  with mycorrhizal fungi and root nodulebacteria, with emphasis on community and ecosystem processes. The  effects of elevated [CO2] on the relationshipsbetween single plant species and root symbionts are considered first.  There is some evidence that plant infection byand/or biomass of root symbionts are stimulated by elevated [CO2], but  growth enhancement of the host seeminglydepends on its degree of dependence on symbiosis and on soil nutrient  availability. Second, the effects of elevated[CO2] on the relationships between plant multispecies assemblages and  soil, and likely impacts on above-ground andbelowground diversity, are analysed. Experimental and modelling work  have suggested the existence of complexfeedbacks in the responses of plants and the rhizosphere to CO2  enrichment. By modifying C inputs from plants tosoil, elevated [CO2] may affect the biomass, the infectivity, and the  species/isolate composition of root symbionts.This has the potential to alter community structure and ecosystem  functioning. Finally, the incorporation of typeand degree of symbiotic dependence into the definition of plant  functional types, and into experimental work withinthe context of global change research, are discussed. More  experimental work on the effects of elevated [CO2] atthe community/ecosystem level, explicitly considering the role of root  symbioses, is urgently needed.