[Phosphoric stress and antioxidative power of wheat roots].

The change of antioxydative power of metabolites in the wheat root system (cv Polesskaya 90 and cv Polesskaya 92) under effect of stress doses of phosphoric nutrition (4-fold dose and phosphoric deficit in nutrient mixture of water culture) proves that phosphoric stress causes peroxidation of membrane lipids. These changes are a nonspecific reaction of membranes in root epithelial cells. Stress and responsive changes in the membrane system are recorded by an antioxydative power decreasing root metabolites. This is the first stage of plant biochemical adaptation (7 to 14 days of growth). The second stage (21 to 28 days of growth) is characterised by the increasing of antioxydative power. However, nonspecific character of the primary reaction of membrane system in root cells at high doses and phosphoric deficite in nutrient mixture changes into clear specific reaction at physiological adaptation level. This is revealed in the change of growth function and kinetics of phosphoric accumulation. Phosphoric deficiency at critical phosphoric concentration in plant roots (0.2% P2O5 of dry mass) results in the increase of growth processes. This is revealed in accumulation of root biomass. At high phosphoric concentrations (1.04% P2O3) the development of root system is inactivated and phosphoric absorption is decreased. The similar specificity in the changes of growth and absorption function of root system is considered to be adapting. The changes of antioxydative power and hence the destroying apparatus in epithelial cells of root system advance the damage at physiological and morphological level and can define wheat adaptation ability to extreme conditions of phosphoric nutrition.