Figure 7

Concentrations (± SE) of total soluble phenolic compounds (TSPC), 4-hydroxybenzoic (4-HX), ferulic (FER), and p-coumaric (P-CM) phenolic acids, and lignin-thioglycolic acid (LTGA) derivatives in rice roots from susceptible (Ss) and resistant (Rr) cultivars with different levels of natural infestation of the South American rice water weevil Oryzophagus oryzae at 25 days after flooding (DAF). Rice cultivars: PAMP = BRS Pampa CL (Ss) (light gray columns); DAWN = Dawn (Rr) (dark gray columns). Levels of natural infestation of larvae on plants selected for biochemical analysis at 25 DAF (larvae infestation peak in the field) = 1 (control): 0 larva; 2: 1–3 larvae; 3: 5–7 larvae; 4:9 larvae. Different lowercase letters above bars denote significant differences among rice cultivars at each infestation level, whereas different uppercase letters above bars denote significant differences in the same rice cultivar among infestation level, both by the Scott Knott test (P ≤ 0.05).