Stomatal responses to carbon dioxide and soil fertility in six genotypes of Populus tremuloides.

Abstract

Stomatal density, in the form of a stomatal index term, was calculated for six genotypes of Populus tremuloides. Two variables, high and low soil fertility and elevated and ambient CO2 levels were used in conjunction with each other to form four different treatments. Stomatal density, epidermal cell density, stomatal length, and leaf area were all recorded. Stomatal index decreased significantly at elevated CO2 levels. Stomatal index, stomatal density and stomatal length differed significantly between genotypes, but not in conjunction with response to elevated CO2. Soil fertility and leaf area did not play significant roles in response to elevated CO2.