Quantitative Analysis of the Grotvth o/Helianthus annuus. 375 



The recorded temperatures — in our case taken at hourly intervals — are 

 tabulated. For each temperature, the rate of the reaction (i.e., respiration) 

 is obtained from the temperature-respiration curve. The arithmetic mean of 

 these is taken, and the corresponding temperature obtained from the tem- 

 perature-respiration curve. 



The total observed production of carbon dioxide was 299 mgrm., whilst the 

 calculated value was 326 mgrm. This agreement is good, considering the 

 fact that a falling off in the rate of respiration must have occurred during 

 the periods when high temperatures obtained. The results of the experiment, 

 as a whole, show that a satisfactory allowance for fluctuating temperature 

 can be made by means of the temperature-respiration curve, at least during 

 the earlier stages of the life-cycle, to which the above experiment applies. 



5. The Decrease with Age in the Respiratory Index of the Plant and of 



its Farts. 



We may now proceed to the main issue, namely, the determination of the 

 respiratory index of the whole plant and of its parts throughout the life- 

 cycle. 



The results of the actual experiments are given in Table IV. 



Table IV. — Observed Eespiratory Index of Plants of Different Age. 



Days 







Eespiratory inc 



ex (mgrm. CO3 per 







Number 



Dry- 



gramme dry-weight per hour) of 



Total 

 inflores- 

 cences. 



Flowers 



from 



of 



weight of 











on 



gernaina- 



plants 



a single 











lateral 



tion. 



used. 



plant. 



Entire 

 plant. 



Stem. 



Leaves. 



Stem-apex. 



shoots. 







grm. 















I 



30 



-0225 



2 -90 













2 



25 



-0223 



3-00 













4 



25 



0-0242 



3-00 













13 



10 



-1009 



2-80 













22 



8 



0-630 



3-00 



(3 -00) 



(3 -00) 



3-00 







29 



2 



4-065 



2-30 











36 





12-85 



1 -21 



0-81 



1-56 









43 





22 -05 



1-03 



0-69 



1-38 









50 





45-15 



-94 



0-46 



1 -52 



2-56 







59 





93 -20 



0-66 



0-33 



1 -32 



1 -72 







64 





98 -30 



0-71 



0-34 



1 -24 









89 





294 -7 



0-48 



6-31 



0-90 



1 -13* 



1-13 





99 





377 -4 



0-37 



0-25 



0-46 



0-89 



1 -04 



1-31 



112 





818-3 



0-26 



0-098 



0-375 



0-75 



0-85 



0-95 



136 





419-5 



0-39 



0-081 



0-44 



0-96 



-965 



0-97 



* From this date onwards the stem-apex was the inflorescence only. 



In the first place, with regard to the plant as a whole, in applying 

 these results for the purpose for which they were intended, namely, for 

 VOL. xcii. — B. 2 F 



