The mode of action and selectivity of oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] were investigated in tolerant rice (Oryza sativaL.) and susceptible barnyardgrass [Echinochloa crus-galli(L.) Beauv. ♯3ECHCG]. Oxadiazon produced only brown spots on the foliage of rice plants at higher rates (> 500 ppmv), while LC50for barnyardgrass was 250 ppmv. Translocation of14C-oxadiazon from the treated leaf was minimal in both species; after 7 days, about 2 and 3% of applied14C translocated in rice and barnyardgrass, respectively. In rice,14C recovered in water and chloroform washings of the treated leaf was 25% in each and in barnyardgrass, 20 and 18%, respectively. After water and chloroform washings,14C-oxadiazon present in the treated leaf of barnyardgrass and rice was 36 and 26%, respectively. In rice and barnyardgrass, unaltered14C-oxadiazon represented 86 and 79% of applied14C, respectively, 7 days after application. In barnyardgrass 7 days after foliar application, oxadiazon inhibited14CO2fixation and the export of fixed carbon. The effects were less marked in rice.
Differential Transcript Levels of Genes Associated with Glycolysis and Alcohol Fermentation in Rice Plants (Oryza sativa L.) under Submergence Stress