Abstract
Rumex obtusifolius L. (perennial weed; Polygonaceae) is one of the oxalate-rich plants. Nevertheless, the mechanism of oxalate accumulation in plants is still unclear. Recent metabolome analyses of R. obtusifolius revealed that oxalate contents were highly correlated to citrate and ascorbate (Miyagi et al, Metabolomics, 2010a, b). We reported that oxalate content in leaves was affected by carbon source (such as citrate) in stems. Using CE-MS, we analyzed the carbon effects on oxalate accumulation and other metabolite levels in leaves and stems of R. obtusifolius. The experiment using 13CO2 showed that 13C-oxalate was highly accumulated in leaves and that 13C mobilization from stems to "new leaves" was observed. High CO2 (1000 ppm) experiment showed that oxalate content was increased by high CO2 with Hoagland's solution, although oxalate levels was not changed by CO2 alone.