Senile Changes in Leaves of Certain Plants 



335 



the older ones; therefore the use of dry weight as the basis would show 

 a still greater difference in favor of the rapidity of production of carbon 

 dioxide in the younger vines than is evidenced in the following data, 

 in which the green weight is used. 



Weighings, and determinations of percentage of carbon dioxide 

 eliminated, were made at the intervals stated in the tables, in which 

 also the total percentage of carbon dioxide eliminated is given. This 

 total percentage is figured as the average rate of ehmination per hour 

 for the entire period of the test. 



TABLE 47. 



Rate of Elimination of Carbon Dioxide from Picked Leaves of Vitis 



VULPINA WITH 20, 6, and 8 RiNGS 





■ 



Age 



years) 



Weight 

 of ten 

 leaves 



(grams) 



Weight in grams of carbon dioxide eliminated 

 in successive periods of 



Total 

 number 

 of hours 



Percentage 



of carbon 



dioxide 



( 



22i hours 



26^ hours 



46f hours 



23| hours 



per green 

 weight 

 per hour 



20 

 6 



8 





26.6 

 33.3 



48.7 



0.2744 

 0.6507 

 0.5662 



0.0534 

 0.0665 

 0.1270 



0.2374 



0.3478 

 0.3904 



0.0675 

 0.1986 

 0.4060 



119i 

 119i 

 119i 



.020 

 .032 

 026 









TABLE 48. 



Rate of Elimination of Carbon Dioxide prom Picked Leaves of Vitis 

 VULPINA with 5, 6, 25, 8, 25, 20, and 8 Rings 



Age (years) 



Weight 

 of ten 

 leaves 



(grams) 



Weight in grams of carbon dioxide 

 eliminated in successive periods of 



Total 

 number 

 of hours 



Percentage 



of carbon 



dioxide 





20 hours 



23 hours 



26 hours 



per green 



weight 



per hour 



5 



6 



25 



8. 



6.5 

 7.4 

 14.6 

 20.0 

 26.5 

 12.0 

 9.8 



0.0778 

 0.0211 

 0.0870 

 0.0637 

 0.0076 

 0.0125 

 0.0092 



0.0917 

 0.0408 

 0.2115 

 0.2456 

 0.2286 

 0.1819 

 0.2540 



0.0678 

 0.1288 

 0.1765 

 0.2504 

 0.4424 

 0.1462 

 0.1262 



69 

 69 

 69 

 69 

 69 

 69 

 69 



0.052 

 0.038 

 0.047 

 041 



25 



20 



8 



0.037 

 0.041 

 057 







