Resource availability affects differentially the levels of gallotannins and condensed tannins in Ceratonia siliqua

Abstract

Abstract Young potted seedlings of the Mediterranean evergreen sclerophyll Ceratonia siliqua were grown in the field under two nutrient and water regimes during the spring growth period. As expected, plants receiving additional nutrients accumulated more above and below ground biomass while the reverse was true for water stressed plants. In accordance with the growth–differentiation balance hypothesis, total leaf phenolics and tannins (astringency) decreased under high nutrients and increased under water stress, with the effects being more pronounced in young leaves. However, the responses of the two tannin types to resource availability were not similar. Only condensed tannins were decreased by nutrient addition while both condensed and gallotannins were increased by water stress. This non-homogeneous behaviour may reflect the different biosynthetic origins of the two tannin types.