LE3 .A278 2007

2007

Kristie, David
Reekie, Edward

Acadia University

Master of Science

Masters

Biology

Biology

I carried out two sets of experiments to investigate the mechanism of how CO2 affects light mediated development in 'Arabidopsis thaliana'. In the first experiment 6 lines of light receptor mutants as well as the wild type of 'Arabidopsis' were grown under five light conditions: complete darkness, white, red, blue and far red light, and two CO2 levels: 380 ppm and 1000 ppm. Analyses based on heights of 5-day old seedlings revealed that elevated CO2 significantly affected seedling elongation under blue and white light, but had no effect under red light, far red light or complete darkness. This result together with the fact that no interaction between line and CO2 was detected under any of the light conditions, suggests that although CO2 can affect 'Arabidopsis' seedling elongation through a blue light mediated pathway, this effect does not require the blue light receptor cryptochrome 2 or phytochrome A as a component. In the second experiment 13 lines of flowering time gene mutants as well as the wild type of 'Arabidopsis' were grown under short and long daylengths at either ambient or elevated CO 2 levels. Based on leaf number at bud formation, an interaction between CO2 and blue light was again implicated. Mutant comparison indicates that the blue light receptor, cryptochrome 2, was involved in mediating the CO2 effect on time of flowering. The 'CRY2' involved mediation, as well as the observed 'gigantean' ('GI ') mediation of the CO2 effect on time of flowering, was found to be related to different daylength patterns, possibly due to the unique expression patterns of these genes. In addition to the interaction with the photoperiod pathway, my results also suggest that the CO2 effect on time of flowering may involve the autonomous flowering pathway.

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https://scholar.acadiau.ca/islandora/object/theses:3090