Table I. 31P-NMR determined cytosolic and vacuolar glyphosate (in vivo analysis) content and ATP and S3P (extraction, in vitro analysis) content in mature GR horseweed leaves

Leaf tissue was either (1) fully immersed for 14 h in the dark in buffer (20°C) containing 10 mm glyphosate, which was equilibrated (via bubbling) with air or with 100% oxygen; or (2) allowed to float for 14 h in the light (150 μE m−2 s−1) on top of buffer (20°C) containing 10 mm glyphosate, which was fully exposed to air (but in the absence of gas bubbling). Data are reported as means ± se (n ≥ 3) and reflect the ratio of individual resonance amplitudes to that of the external reference (MDP). Extract results (ATP and S3P) are normalized to per gram leaf wet weight.

ParameterAir Saturation (Dark)Oxygen Saturation (Dark)Air Exposure (Light)
In vivo analysis
 Cytosolic glyphosate0.31 (0.04)0.03 (0.01)0.03 (0.01)
 Vacuolar glyphosate0.09 (0.01)0.58 (0.03)0.39 (0.04)
 Sum0.40 (0.05)0.61 (0.04)0.42 (0.05)
 Cytosolic/vacuolar glyphosate3.40 (0.05)0.05 (0.04)0.08 (0.05)
Extract analysis
 ATP0.18 (0.05)0.28 (0.04)0.30 (0.02)
S3PNot detectable1.38 (0.05)2.06 (0.76)