3 



ANAEROBIC RESPIRATION 03 



hydrogen^ is formed by the anaerobic respiration of plants 

 containing mannite, since mannite undergoes hydrolytic 

 cleavage into sugar : 



CH2OH— (CHOH) 4— CHaOH-^CHaOH— (CHOH) 3 



— CO— CH2OH + H2 



Kostychev- proved by detailed experiments that hydrogen 

 is never formed in anaerobic respiration. Hydrogen is actually 

 formed by the fermentation of mannite only with a bacterial 

 infection. This process has nothing to do with the physiological 

 transformations in plants containing mannite. 



3. ANAEROBIC RESPIRATION UNDER NATURAL CONDITIONS 



Only a few plants exhibit anaerobic respiration under natural 



Hving conditions. Some inhabitants of marshes and plants 



which grow on annually submerged lands, some seeds at certain 



stages of germination, some fruits, and living wood parenchyma 



cells are probably to be included in this group. V. Polowzow 



alluded to the fact that at certain stages of germination, maize 



, r CO2 , 

 and pea seeds exhibit a considerable magnitude of — — and 



O2 



form alcohol, and that the anaerobic phase exists along with 



the normal respiration. This investigator thought he could 



show that, with slow growth and an excess of sugar, alcoholic 



fermentation generally appears as a normal phenomenon in 



seed-plants with free access to oxygen. This concept is by 



no means entirely correct. It shows that with the given seeds 



a deficiency of oxygen appears during the germination. ■• This 



deficiency is due to the presence of firm seed coats which are 



but slightly permeable to oxygen. As soon as these coats are 



removed a strong absorption of oxygen follows, and the alcohol 



which accumulated in the li\dng cells is quickly consumed. 



1 Humboldt. Flora friburgensis. 1793; Marcet. Ann. de chim. et de physique. (II.) 

 40: 218; Muntz. Ibid. (V.) 8:67. 18-6; de Luca. Ann. sci. nat. bot. (VI) 6:286. 



J Q - Q 



^Kostytschew, S. Ber. d. bot. Ges. 24: 436. 1906; 25: 178. 1907; Physiol.-chem. 

 Untersuch. iiber Pflanzenatmung. 1910. Russian. 



3 Polowzow, V. Untersuch. liber die Pflanzenatumng. 1901. Russian. 



4 Kostytschew. S. Biochem. Z. 15: 164- i9o8; Physiol.-chem. Untersuch. iiber die 

 Pflanzenatmung. 1910. Russian. 



