Submitted to: The Plant Cell
Publication Type: Abstract Only
Publication Acceptance Date: July 27, 2001
Publication Date: N/A
Technical Abstract: This study investigated the responses of metabolites and soluble leaf proteins to plant growth in elevated carbon dioxide. Arabidopsis thaliana (Columbia ecotype) plants were grown in controlled environment chambers with ambient (35 Pa) and elevated (100 Pa) carbon dioxide, 0.3 mmol m-2 s-1 PPFD and with a 16-h light/8-h dark photoperiod for 2- to 6-weeks. Starch and sucrose were increased by 57% and 30%, respectively, in rosettes of 6-week-old plants grown at elevated compared to ambient carbon dioxide. Biomass accumulation also was greater between 2- and 5-weeks in response to enhanced carbon dioxide, although this difference was not detected after 6-weeks growth. The elevated carbon dioxide treatment delayed flowering, such that flowering was observed for 52% and 100% of 4-week-old elevated and ambient carbon dioxide grown plants, respectively. Nitrate varied with plant age and fertility treatments, although mean nitrate levels were decreased 58% by carbon dioxide enrichment. Chlorophyll, the chlorophyll a/b ratio, carotenoids and total soluble protein levels did not differ between treatments. However, both the large and small subunit proteins of Rubisco were decreased and the overall profile of soluble proteins was altered by growth in elevated carbon dioxide after separation by 2-D gel electrophoresis. In agreement, total Rubisco activity decreased with plant age and also was lower in the elevated compared to the ambient carbon dioxide treatment. The above results demonstrated that N-limited senescence probably did not occur in the carbon dioxide enriched plants. Nevertheless, large alterations in individual proteins were detected between the two carbon dioxide treatments.