Infiltration of methyl viologen (MV, source of O2-) and Na-diethyldithiocarbamate (DDC, inhibitor of SOD) into wheat leaves resulted in the accumulation of active oxygen species and photo-oxidative damage to photosynthetic apparatus under both moderate and high irradiance. Exogenous antioxidants, ascorbate (ASA) and mannitol, scavenged active oxygen efficiently, protected the photosynthetic system from MV and DDC induced oxidative damage, and maintained high Fv/Fm [maximal photochemical efficiency of photosystem 2 (PS2) while all PS2 reaction centres are open], Fm/F0 (another expression for the maximal photochemical efficiency of PS2), ΦPS2 (actual quantum yield of PS2 under actinic irradiation), qP (photochemical quenching coefficient), PN (net photosynthetic rate), and lowered qNP (non-photochemical quenching coefficient) of the leaves kept under high irradiance and oxidative stress. Phenolic compounds used in these experiments, catechol (Cat), resorcinol (Res), and tannic acid (Tan), had similar anti-oxidative activity and protective effect on photosynthetic apparatus as ASA and mannitol. The anti-oxidative activity and the protective effect of phenolic compounds increased with increase in their concentration from 100 to 300 g m-3. The number and the position of hydroxyl group in phenolic molecules seemed to influence their antioxidative activity. and Hui Jie Zhao, Qi Zou.
The effects of tannic acid on mean values and genetic variation in fitness-related traits (mass, relative growth rate) and specific activities of digestive enzymes (total proteases, a-glucosidase and lipase), and genetic variation in their plasticity, were investigated in fifth instar larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae) originating from two populations with different host use histories (oak and locust-tree). The two populations did not differentiate with respect to fitness-related traits, i.e. adverse effects of tannic acid were similar in both populations. However, Robinia larvae, which originated from the locust-tree forest, were characterized by higher total protease and lipase activity and lower a-glucosidase activity than Quercus larvae, which originated from the oak forest. Higher plasticity of lipase and lower plasticity of a-glucosidase in response to tannic acid were also recorded. Quantitative genetic analysis revealed mostly significant expression of genetic variation in the examined traits and trait plasticity, suggesting the potential for evolution of adaptive plastic responses to new environmental conditions and presence of a stressor. The genetic correlations observed between the environments significantly differed from “one”, which indicates there are no constraints on the evolution of trait plasticity., Marija Mrdakovic ... [et al.]., and Obsahuje seznam literatury