Antioxidative capacity of oak trees - Tannins as a substantial prerequisite for a provenance-specific response to drought.

Adult Sessile and Pedunculate oak (Quercus petraea Liebl. & Q. robur L.) and their offsprings were assessed for the antioxidative capacity. The antioxidative capacity is a quantitative trait for the capability of animate beings to remove reactive oxygen species by means of antioxidants. Factors were climate and weather drought constraints, oxidative load, biomembrane damage, antioxidative system and tannins. There was substantial total antioxidative capacity of about 400 µmol ascorbate-equivalents / g dry matter in the Sessile and Pedunculate oak leaves, however, unimpacted by adverse environments (cf. Tab. 4, 5). Instead, it is correlated to total phenolics in a clearly positive way, particularly through the essential oak ellagitannins vescalagine and castalagine (cf. Fig. 3, 4). Total phenolics driven antioxidative capacity is accumulated in convenient environments and consumed in adverse situations. When grown under common conditions offspring from humid oldgrowth stands tended to accumulate more total antioxidative capacity in a favourable environment and used it up under drought constraints. On the other hand, the saplings from arid oldgrowth stands held their total antioxidative capacity constant even in a more adverse environment (cf. Fig. 5; Tab. 8). [ABSTRACT FROM AUTHOR]