44 



Lewis Knudson 



Maige and Nicolas (1910) studied the influence of various concentra- 

 tions of different sugars on the turgescence and respiration of etiolated 

 shoots of bean and the excised embryo of kidney bean. The plant material 

 was immersed in the sugar solutions and the respiratory rate was then 

 measured. The experiments were not made under sterile conditions, 

 but since the duration of the respiration determination was but one hour 

 this precaution was not necessary. With the etiolated shoots of bean 

 the following data were obtained on the relative increases in evolution 

 of carbon dioxide, the intake of oxygen, and the respiratory coefficients. 

 The concentration of sugar was 10 parts per 100. 



Carbon 

 dioxide 



(CO.) 

 (grams per 



hour) 



Oxygen 



m 



(grams per 

 hour) 



CO2 

 O2 



Saccharose 

 Maltose. . . 

 Lactose. . . 

 Glucose . . . 

 Fructose . . 



1.73 

 1.47 

 1.05 

 1.75 

 1.33 



1.28 

 1.26 

 0.95 

 1.32 

 1.10 



1.35 

 1.16 

 1.09 

 1.32 

 1.20 



According to these investigators the influence of the sugar depends on 

 its penetration, and the relative increase in respiration follows the order 

 of penetrability. Similar results were obtained with the embryo of kidney 

 bean. It is probable, however, that other factors than the degree of 

 penetrability determine the respiratory values. The results of Maige 

 and Nicolas do not agree with those obtained by Palladine, since in the 

 former fructose has the fourth place in order of influence on respiration. 



Molliard (1907) measured the respiration of aerial parts of radish 

 which had been grown for about two months in cultures with and without 

 sugar. The plants supplied with glucose and fructose showed a greater 

 evolution of carbon dioxide per gram of dry matter per hour than did 

 the plants grown in the culture medium without sugar. 



Lubimenko (1906 a) investigated the influence of various sugars on the 

 respiration of the plantlets of Pinus Pinea which were grown from embryos 

 separated from the seeds. The plants were grown under sterile conditions. 



