PMC

HPLC chromatogram of the phenolic acids (acidic fraction) from V. zizanioides leaves. The values represent retention time (R _t) in min. a: p hydroxybenzoic acid, b: p coumaric acid, and c: ferulic acid.

Changes in monomeric phenolic acid contents in wine with different copper concentrations. (A1) Gallic acid; (A2) protocatechuic acid; (A3) gentisic acid; (A4) p-hydroxybenzoic acid; (A5) syringic acid; (A6) vanillic acid; (B1) p-coumaric acid; (B2) caffeic acid; (B3) sinapic acid; (B4) ferulic acid; (B5) chlorogenic acid; (C1) total hydroxybenzoic acids; (C2) total hydroxycinnamic acids; and (C3) total phenolic acids. Different letters indicate statistically significant differences (Duncan’s multiple range test, p < 0.05) between samples with different copper concentrations.

Biplot diagram representing results of redundancy analysis (RDA) on the effects of light intensity (Light), CO₂ concentration (CO₂), barley variety (Barke, Bojos) on the localization of PhCs within leaf cross-section (light purple; AD—adaxial mesophyll layer, UM—upper mesophyll, MM—middle mesophyll, LM—lower mesophyll and AB—abaxial mesophyll layer), content of hydroxycinnamic acids (orange; Cou—3-coumaric acid, Caf—caffeic acid, Fer—ferulic acid, Sin—sinapic acid, Chlo—chlorogenic acid), hydroxybenzoic acids (brown; Ben—3-hydroxybenzoic acid, Pro—protocatechuic acid, Van—vanillic acid, Syr—syringic acid), flavones (red; Api—apigenin, Lut—luteolin, Iso—isovitexin, Hom—homoorientin, Sap—saponarin), chlorophyll index (Chl) and UV screening of chlorophyll fluorescence (UVscr). Explained variation by axis 1 = 82.8% and cumulative explained variation by both axis = 91.6% (Pseudo-F = 25.9, p = 0.002).

Phenolic compounds in asymptomatic and symptomatic leaves of vines affected by brown wood streaking, grapevine leaf stripe and apoplexy; their levels (dry weight basis) progressively increased with increasing severity of symptoms. The legend is as in Figure 6. Error bars = standard deviations (n = 4); different letters above the columns denote statistical differences (Tukey’s test; P ≤ 0.05); cinnamic = cinnamic acid; chlorogenic = chlorogenic acid; hydroxybenzoic = hydroxybenzoic acid; i-glc = isorhamnetin-3-O-glucoside; and k-glc = kaempferol-3-O-glucoside.