A MODEL SYSTEM TO STUDY THE EFFECTS OF ELEVATED CO2 ON THE DEVELOPMENTAL PHYSIOLOGY OF ROOTS - THE USE OF ARABIDOPSIS-THALIANA

Three developmental changes were observed in the roots of Arabidopsis thaliana (Columbia) when shoots were exposed to elevated CO2, (i) The allometric coefficient, k, was enhanced significantly (P<0.001), (ii) primary root length and root extension rate were enhanced (P<0.001), A ccelerated cortical cell expansion contributed to this effect and was associated with increased cell wall extensibility, measured as % plast icity. (iii) Lateral root formation and extension were also increased in elevated CO2 (P<0.05). These results illustrate that root growth an d structure was altered following exposure to elevated CO2, The change s observed suggest that Arabidopsis provides a useful model which shou ld, in future, be amenable to study using appropriate mutants allowing the genetic basis of the responses to be identified.