Mechanical grass fractionation

Sethoxydim (IpM) inhibited the biosynthesis of fatty acids in isolated oat chloroplasts (measured via [14C]acetate incorporation into the total fatty acid fraction) to ca. 60 %, whereas in the isolated chloroplasts of the dicotyledonous pea plants their synthesis was not affected by sethoxydim. About 50 % inhibition of fatty acid synthesis by IpM sethoxydim was detected in experiments with chloroplasts isolated from Poa pratensis, a herbicide-sensitive grass. In chloroplasts isolated from Poa annua, which as a whole plant is tolerant against sethoxydim [7], fatty acid biosynthesis was also blocked (to ca. 45 %) by IpM sethoxydim (Fig. 2). This indicates a basic difference in the mechanism of tolerance for Pisum sativum and Poa annua, respectively. In Poa annua, the tolerance is apparently based on... 

---