RESPIRATION 



193 



The succulent plants in the first series, it will be noted, respire on an average 

 far less actively than the others. 



As examples of excessive respiratory activity, Garreau's (1851) data, 

 obtained from germinating seeds, may be next quoted : — 



The same investigator gives the following values for buds 



Plant. 



Syringa 



Santbucus nigra 

 Ribes nigrum 

 Tilia europea 



Temperature. 

 15° c. 



Fresh weight 

 of buds. 

 90 gr. 

 100 ,, 



4.0 ,, 



Dry weight 

 of buds. 

 2.0 gr. 

 1-75 ,, 

 1-25 ,, 

 0-70 ,, 



CO2 in 

 24 hrs. 

 70 ccm. 

 60 ,, 

 60 „ 

 46 „ 



CO^ per I gr. 

 of dry weight. 



35 ccm. 



34 „ 



48 „ 



66 „ 



These numbers cannot be directly compared with those obtained by Saus- 

 SURE (1804) (compare Sachs, 1865, p. 277) for flowers and floral organs, be- 

 cause that author estimated the volumes of oxygen absorbed and reckoned the 

 volume of the organ in question as unity. His results are, all the same, of great 

 interest because he investigated not only the flowers but also the leaves of the 

 same plants in darkness. 



Finally, a few examples may be quoted by way of demonstrating the 

 variations which occur during development, and the first of these is of interest 

 as giving the absolute amount of respiration. The inflorescence of Arum used 

 up the following amounts of oxygen (in ccm.) in successive hours (Garreau, 

 1851) :— 



