XVI International Botanical Congess
Elevated concentration of CO2 may exert important effects on parasitic angiosperm-host associations through impacts on host and parasite gas exchange. The degree of these impacts is a function of the extent to which host response to infection are source-sink driven, the degree of parasitic autotrophy for carbon, host photosynthetic type (C3 vs C4) and the extent to which nutrients and water limit growth and photosynthesis. Community-level impacts (under bother ambient and elevated VC=CO2) are likely to be driven by competitive interactions. Such interactions will operate both between host and parasite for resources within the vascular system and between host and non-host species for resources in the atmospheric and edaphic environment. In addition, parasitic angiosperm may impact on nutrient cycling, thus providing a second mechanism controlling their impact ant the community level.