IN rice coleoptile cells mitochondria can be formed and preserved without any notable signs of destruction in the absence of molecular oxygen1,3. In this, rice coleoptiles are strikingly different from other plant tissues, whose fine cell organisation is degraded during even a short-term anaerobiosis4–6. In the experiments mentioned, however1–3, the rice seeds were grown from the very beginning under oxygen-free conditions. This excluded not only the possibility of functioning of mitochondria but, probably also, their normal formation. One could therefore suppose that such mitochondria as yeast promitochondria7,8 do not contain all the carriers of the respiratory chain and possess an enhanced resistance to anaerobiosis. High resistance of cell ultrastucture to anoxia could be, on the other hand, secured by intensive energy output through glycolysis.