Figure 4

Humoral immunity of cotton bollworm larvae fed with wheat grain grown under ambient and elevated CO₂ levels with M. mediator.

(a) Phenoloxidase activity (A_490 nm min⁻¹ mg protein⁻¹) and (b) Melanization ratio (%) of H. armigera larvae (sampled at 24, 48, 72 and 96 h post parasitization). A: ambient CO₂ without parasitism; E: elevated CO₂ without parasitism; A + P: ambient CO₂ with parasitism; E + P: elevated CO₂ with parasitism. Each value of PO activity represents the mean (±SE) of 5 replicates; each value of melanization ratio represents the mean (±SE) of 6 replicates; Different lowercase letters indicate significant differences among the combinations of parasitism treatment and CO₂ concentrations within the same sample time. Different uppercase letters indicate significant differences among the different sample time within the same parasitism and CO₂ treatment as determined by LSD test at P < 0.05).