= 2.005 



Z 



g 



z 

 g 



I— 



a. 



o 



CO 



CO 



< 



< 



o 



MAGNETIC FIELD 



Fig. 2. ESR signal from spinach chloroplasts (washed twice with 0.5 M sucrose) 

 in the dark and during ilhuiiinalion with wliiic Hglit. The lower cur\es repre- 

 sent the original I'.SR signals; magnetic held increases toward the right along the 

 ahscissa, and tiie ordinate represents the rate of change with respect to field strength 

 of microwave energy (9000 Mc/sec) ahsorhcd by the sample. Tiie uppermost 

 curves represent machine integrals of the lower curve; below them is the absorp- 

 tion due to the effect of light alone which is obtained by subtracting the dark 

 integral curve from the light integral (ur\e. Modulation am])Iitudc: 8 gauss. 

 1-iginc from reference (.5). 



364 



