The Relationship Between Endogenous ß-Glucuronidase Activity and Biologically Active Flavones-Aglycone Contents in Hairy Roots of Baikal Skullcap.

Here, we examine the relationship between contents of principal flavones in hairy roots of Scutellaria baicalensis with the activity of the ß-glucuronidase (sGUS) enzyme during a culturing cycle. Using RP-HPLC, we show that the highest contents of aglycones, baicalin and wogonin is observed at the growth days 8, 14, and 71 and reach 45, 41, and 62% (based on the total weight of hairy roots of the Baikal skullcap), correspondingly. Their accumulation is accompanied by increase of the sGUS activity, which we determined fluorometrically. Moreover, the enzyme activity is characterized by significant and reasonable correlation only with the wogonin contents. Our results confirm a significant role of sGUS at the final steps of the metabolism in root-specific flavones of Baikal skullcap and suggest how one can optimize the conditions of culturing the hairy roots for biotechnological production of individual flavonoids. For example, at the culturing day 71 wogonin constituted over 80% of all flavones extracted from cells.

Functional electron microscopy in studies of plant response and adaptation to anaerobic stress.

This article reviews the contribution made by functional electron microscopy towards identifying and understanding the reactions of plant roots and shoots to anaerobic stress. Topics examined include: (1) unexpected hypersensitivity, rather than hyper-resistance, to anoxia of root tips of flooding-tolerant plants; (2) protective, rather than damaging, effects of a stimulated energy metabolism (glycolysis and fermentation) under anaerobic conditions; (3) the concept of two main strategies of plant adaptation to anaerobic environments, namely avoidance of anaerobiosis on the whole plant level, termed 'apparent' tolerance, and metabolic adaptation at the cellular and molecular levels, termed 'true' tolerance; (4) the importance of protein synthesis during hypoxia and anoxia for enhanced energy production and metabolic adaptation; (5) a general adaptive syndrome in plants to stress at the ultrastructural level and a possible molecular mechanism for its realization under anoxia; (6) the physiological role of anaerobically synthesized lipids and nitrate as alternative electron acceptors in an oxygen-free medium; and (7) the selection of cell lines derived from callus cultures that possess enhanced tolerance to anoxia and can regenerate whole plants with improved tolerance of soil waterlogging.