This review attempted to follow the establishment of a novel branch of biology arisen at the interfaces between plant physiology, biochemistry, and molecular biology-plant anaerobic stress. Most attention was given to the early period of these investigations, the activity of the members of International Society for Plant Anaerobiosis in particular, and the contribution of Russian scientists, who played a significant role at that time in the establishment and international recognition of this new trend. In this connection, the following points are considered: (1) Crawford's metabolic theory, which could not withstand experimental verification but induced an active discussion, thus stimulating, further investigations in this field; (2) a concept of two main strategies of plant adaptation to anaerobic stress (true and apparent adaptation), which was put forward based on the following experimental data: (a) a discovery of a paradoxical phenomenon of hyper-sensitivity, but not hyper-resistance to anoxia, of the flood-tolerant plant roots ("apparent" tolerance); (b) the elucidation of the physiological role of oxygen transported from aerated organs of flood-tolerant plants to the roots inhabiting anaerobic environment; (c) demonstration of the key role of both energy metabolism, and (d) substrate providing for glycolysis and ethanolic fermentation in plants manifesting "true" tolerance to oxygen deprivation; (3) the discovery cry of plant stress proteins; and finally (4) pH-stat theory put forward by Davies.
