(2) Mineral absorption and
transport by roots might be restricted under elevated CO2.
On one hand, elevated CO2 can stimulate the growth and
activities of rhizospheric microorganisms (Hu et al. 2001)
and thus accelerate the competition of mineral uptake between
roots and microorganisms (Cheng 1999), which might
limit mineral absorption by roots. On the other hand, elevated
CO2 can alter the tissue composition of plant organs
(Booker and Maier 2001), which might affect the mineral
transport from roots to aboveground organs.