24 The Philippine Journal of Science 
Table 12. — Temperature coefficients of photosynthesis, having the order 
of photochemical coefficients. 
Range of temperature — 
Studied. 
In which 
photochemi- 
cal coeffi- 
cients are 
valid. 
Coeffi- 
cient. 
Investigator. 
Plant studied. 
°C. 
-6 to +40.5 
°C. 
+3 to 38.3, 
1.0+ 
Matthaei 
Cherry laurel. 
+7 to 21 
13 to 21 
1.35 
Blackman and Smith 
Elodea. 
24 to 45 
24 to 40 
1.26 
Van Ametel 
Do. 
2. 3 to 46.4 
11. 3 to 25 
1.16 
Kreusler 
Rubus fruticosus. 
9. E to 39 
9. 5 to 39 
1.0+? 
Prjanischnikow 
Typha latifolia. 
The coefficients that we have obtained for photosynthesis are 
much smaller than those for most biological phenomena, since 
the latter, at similar temperatures, have coefficients of the mag- 
nitude required by the van’t Hoff principle. These coefficients 
have been so thoroughly discussed that we need not consider 
them here. For literature on this subject, see the introduction. 
Much of the literature, including many of the minor papers 
on the relation of temperature to photosynthesis, is not available 
in Manila. Therefore, a discussion of all of the literature on 
the subject is impracticable and will not be attempted. The 
work here considered includes that usually quoted as showing 
the relation between temperature and the rate of carbon dioxide 
assimilation. The literature has been discussed in detail by 
Matthaei and others. Such of it as is available is of no interest 
in the present discussion, and the references at our disposal 
indicate that this is true of the remainder. 
The results of our analysis of the work discussed are remark- 
ably consistent and seem to warrant the following conclusions; 
CONCLUSIONS 
The results of the work on carbon dioxide assimilation, here 
discussed, show temperature coefficients of from 1.00 and 1.40 
over long ranges of temperatures which are favorable for this 
process. They are much smaller than those for most vital 
phenomena, which at similar temperatures are generally held 
to be of the order of magnitude required by the van’t Hoff 
principle. 
These coefficients are of the same order of magnitude as photo- 
chemical coefficients, which is not surprising in view of the fact 
that carbon dioxide assimilation is effected by light. 
