FLUORESCENCE-TIME CURVES 



1397 



effect in Ulva lactuca, according to Kautsky and U. Franck (19-i3). At 

 concentrations of the order of 10"^ mole/1., the first fluorescence wave is 

 entirely eliminated, the fluorescence starts high, and a slight decline at the 



18- 



y 16 



z 



UJ 



o 



tr 

 o 



3 



12 



35° 



29° 



19° 



/ / 



r = ioo 



TIME, min. 



Fig. 33.40. Fluorescence-time relations as a function of temperature 

 at three different Ught intensities (after Wassink and Katz 1939). Gas 

 phase, air; total inhibition of photosynthesis by cyanide. Order of curves 

 in first peak, from top down: 2°, 19°, 29°, and 35° C. 



beginning of illumination replaces the normal increase. This decline lasts 

 longer at lower light intensities (fig. 33.42B). The drop in ^ from the 

 initial level to the steady level is greatest at the lowest light intensity and 

 highest temperature. 



