NO.    6  GROWTH    OF    AVENA    COLEOPTILE JOHNSTON  I3 
'llie  marked  differences  in  relative  lengths  of  first  internode  and 
coleoptile  in  the  dark  and  exposed  series  indicate  some  drastic  re- 
distrihuti(jn  of  growth  regulators. 
The  ratios  of  first  internode  and  of  coleoptile  to  total  length  of 
seedling  are  shown  as  percentages  in  table  4.  These  percentages  were 
determined  for  each  seedling  and  then  averaged  for  each  experiment 
and  again  averaged  for  each  wave  length.   This  last  average  is  shown 
Table  4. — Percentage  Length  of  First  Internode  and  Coleoptile  of  Total  Length 
of  Avena  Seedling  for  the  Designated  Wave  Lengtlis  and  Temperatures 
[Average  Data  in  Boldface  Type.] 
In  same  moisture  chamber 
Wave 
length 
E^ 
iposed 
Dark  control 
A 
Separate  chamber 
Dark  control 
Te 
■mperature 
(°E.) 
A 
Int. 
Col. 
Int. 
Col. 
Int. 
Col. 
Max. 
Min. 
Average 
4047 
36 
64 
68 
32 
75 
74 
74-5 
31 
69 
69 
31 
79 
76 
77-5 
51 
49 
88 
12 
79 
76 
77-5 
42 
58 
76 
24 
87 
13 
78 
77 
77-5 
40 
60 
71 
29 
87 
13 
76.8 
4358 
38 
61 
76 
24 
86 
14 
79 
77 
78.0 
40 
60 
76 
24 
86 
14 
78 
76 
77.0 
43 
57 
78 
22 
88 
12 
78 
77 
77-5 
41 
59 
77 
23 
87 
13 
•• 
77-5 
5461 
38 
62 
73 
27 
88 
12 
77 
76 
76.5 
39 
61 
73 
27 
89 
II 
76 
76 
76.0 
41 
59 
74 
26 
87 
13 
75 
75 
75-0 
34 
66 
72 
28 
85 
15 
79 
78 
78.5 
38 
62 
73 
27 
87 
13 
76.5 
5780 
25 
75 
56 
44 
86 
14 
79 
78 
78.5 
29 
71 
60 
40 
87 
13 
80 
79 
79-5 
30 
70 
61 
39 
87 
13 
78 
78 
78.0 
28 
72 
59 
41 
87 
13 
78.7 
in  boldface  type.  Temperature  data  are  given  in  the  last  three  columns. 
But  little  difference  is  to  be  seen  in  the  percentages  of  lengths  of -first 
internodes  and  coleoptilcs  in  the  first  three  wave  lengths.  The  values 
for  5780  A  are,  however,  different.  A  comparison  of  these  per- 
centage values  in  the  two  series  of  experiments  for  the  exposed 
coleoptiles  is  shown  below.  The  wave-length  values  between  the  two 
series  are  not  strictly  comparable  but  are  approximately  correct. 
Each  set  of  values  shows  about  equal  lengths  of  coleoptile  for  the 
first  three  wave-length  values.    The  value  for  the  5780  A  region  of 
