Development of Chlorophyll . 817 
were quite deep green. On the contrary in the first light period in 
Fig. 9, it will be seen that there was a marked rise in the curve, though this 
was probably a big chance fluctuation in the level first part of the starva¬ 
tion curve of respiration. 
TABLE VI. 
Shoot-tips of Vida Faba. 
Developed in dark but exposed, growing, to daylight until their 
normal green colour was attained. 
No. of 
Reading. 
Grams of C 0 2 
given out. 
llhanination. 
Colour of Leaves. 
1 
•0027 
Dark 
Leaves normal 
2 
•0022 
» 
dark green 
3 
•0021 
it 
4 
•OOIO 
Light 
5 
.0007 
9t 
6 
•0000 
99 
7 
* OOI 5 
Dark 
8 
.0016 
» 
9 
.0015 
99 
10 
.0014 
99 
11 
•OOIO 
it 
•0028 
•0026 
•002 4 
0022 
W 
j -0020 
< 
X 0018 
O 
2 0010 
O* 
U 0014 
O *0012 
b 
*? OOlO 
CL 
I” 
O 0006 
o 
•0006 
•0004 
•0002 
Experiment VIII. 
The last experiment to be recorded completes the series by showing 
that etiolated shoots of Vicia seedlings, which have been kept growing in 
daylight longer than those of Exp. VII, 
until they turned their normal dark green 
colour, were able to assimilate the whole 
of the C 0 2 of respiration. 
The detailed results are given in 
Table VI and Fig. 10. 
A series of eleven two-hour read¬ 
ings was made. As soon as the re¬ 
spiration had settled down the chamber 
was illuminated and there was at once 
a big drop in the C 0 2 output, which 
declined rapidly to nothing in reading 6. 
No doubt the photosynthetic power 
was by that time sufficiently developed 
to enable the shoot to utilize additional 
C 0 2 from the outer air had any been 
\ 
L 
V. 
\ 
/ 
3 
6 8 10 12 14 16 
Time in Hours 
is 20 
Fig. 10. 
provided. On darkening, the respiration 
rose again to continue the ordinary 
curve of slowly decreasing values, indicated by the broken line. 
