The effects of elevated CO2 concentrations on cell division rates, growth patterns, and blade anatomy in young wheat plants are modulated by factors related to leaf position, vernalization, and genotype.

摘要

In greenhouse pot trials, wheat cv. Hartog and Birch 75 were vernalized or not vernalized, and exposed to ambient (350 ppm during the day and 420 ppm at night) or increased CO2 (900 ppm day and night). Increased [CO2] increased cell division and expansion in developing wheat leaves, which affected whole-leaf growth kinetics, anatomy and carbon content. However, the expression of these effects was modified by cultivar, leaf position and vernalization. Beyond these interactions, leaf developmental responses to increased [CO2] shared several features that were conserved across all leaves examined: the contribution of [CO2] effects on meristem size and activity in driving differences in whole-blade growth kinetics and final dimensions; an anisotropy in cellular growth responses to elevated [CO2], with final cell length and expansion in the paradermal plane being highly conserved, even when the rates and duration of cell elongation were modified, while cell cross-sectional areas were increased; tissue-specific effects of elevated [CO2], with significant modifications of mesophyll anatomy, including an increased extension of intercellular air spaces and the formation of, on average, one extra cell layer, while epidermal anatomy was mostly unaltered.