A. Hodge, IMPACT OF ELEVATED CO2 ON MYCORRHIZAL ASSOCIATIONS AND IMPLICATIONS FOR PLANT-GROWTH, Biology and fertility of soils, 23(4), 1996, pp. 388-398
The impact of increasing concentrations of atmospheric CO2 upon plant
physiology has been widely investigated. Plant, and in particular root
, growth is nearly always enhanced as a direct consequence of CO2 enri
chment, with C-3 species generally more responsive than C-4 species. S
uch alterations in plant productivity will have consequence for below-
ground processes and increased carbon allocation to the roots may favo
ur symbiotic relationships. This paper discusses the current informati
on available for the consequences of these changes upon mycorrhizal re
lationships. Generally mycorrhizal plants grown under CO2 enrichment s
how enhanced phosphorus uptake but nitrogen uptake is unaffected. This
increased nutrient uptake is not correlated with increased mycorrhiza
l colonization of the roots. Similarly root exudation does not increas
e under CO2 enrichment but qualitative differences have yet to be asse
ssed. However, it is predicted that total rhizodeposition of materials
will increase as will litter inputs, although mineral and biochemical
alterations to these plant derived inputs may occur. The consequences
of such changes within the rhizosphere are discussed and future resea
rch priorities identified.