Plant [bush bean] uptake of bicarbonate as measured with the 11C isotope

¹¹C which is cyclotron produced by ¹⁴N(P, α) ¹¹C(half-life 20.1 M) was used as a tracer of bicarbonate to determine its movements from a nutrient solution through roots to stems and leaves of bush bean plants (Phaseolus vulgaris L. var. Improved Tendergreen). The short time involved and the high solution pH minimized the need for use of the Henderson Hasselbach equation for activity correction. Quantities of ¹¹C did move into roots, stems and leaves with a sharp decreasing gradient (root/stem = 14.5, stems/leaves = 11.7) More ¹¹C moved into plants with KHCO₃ than with NaHCO₃. The (NH₄)₂SO₄ enhanced ¹¹C uptake and KNO₃ decreased it. This enhancement and competition indicated possibility of some uptake of $HC{O_3}^ - $. In an experiment with Galenia pubescens (Eckl. and Zeyh.) Druce, the ¹¹C was more readily moved to stems and leaves than in bush bean indicating substantial uptake of $HC{O_3}^ - $.