Abstract:
The primary effect of the response of plants to rising atmospheric CO2 (Ca) is to
increase resource use efficiency. Elevated Ca reduces stomatal conductance and
transpiration and improves water use efficiency, and at the same time it stimulates
higher rates of photosynthesis and increases light-use efficiency. Acclimation
of photosynthesis during long-term exposure to elevated Ca reduces key enzymes
of the photosynthetic carbon reduction cycle, and this increases nutrient
use efficiency. Improved soil–water balance, increased carbon uptake in the
shade, greater carbon to nitrogen ratio, and reduced nutrient quality for insect
and animal grazers are all possibilities that have been observed in field studies of
the effects of elevatedCa. These effects have major consequences for agriculture
and native ecosystems in a world of rising atmosphericCa and climate change.
