348 



L. R. Blinks 



Figure 2. pH changes of sea 

 water produced by a green 

 filamentous alga, Chaeto - 

 morpha aerea , contained in an 

 "everted" glas s e le c t r ode . 

 Respiration (d) caused a 

 slow fall of pH: red light 

 caused a small "acid gush," 

 followed by a rapid rise of 

 pH. Far red light of the same 

 intensity produced compensa- 

 tion, with no pH drift, as 

 did 6k'^ mji. Doubling the 

 intensity of the latter 

 doubled this rate, while 6^4-5 

 + 702 mp show good enhance- 

 ment, with about 50/0 increase 

 of rate over the expected ad- 

 dition of the individual wave 

 lengths . 



contributed to the buffering of the system, since they are 

 capable of 9ation exchange, including H-ion as shown by Eppley 



capable of cation exchange, inc. 

 and Blinks v9)^ and Eppley (lO) 



Fig. 3 shows the change of pH produced by illumination with 

 red (678 mji) and green (566 mn) light respectively in the case 

 of Porphyra Nereocystis . The former produces a, rapid pH rise, 

 followed, in the coiorse of about 5 minutes, by a slow decrease. 

 The green light causes a slower rise, sometimes with an Induct- 

 ion period (rise, fall and later rise). Darkening causes prompt 

 fall of pH after red light, but often a slower one after green 

 light. 



Fig. 3 also shows chromatic transients, produced by alternat- 

 ion of red and green light. As might be expected from the light- 

 dark time course the red transient consists of a cusp (a) 

 followed by a slow fall to a steady state; the green transient 

 of a rapid drop, followed by rather quick recovery. The size 

 of these chromatic transients was usually 10 to 15'^ of the steady 

 rate, but occasionally, especially with tissue which had been on 

 the electrode for considerable time, might become much larger, 

 reaching 50^ in extreme cases. It is believed that some of these 

 represented warming of somewhat dehydrated tissue. In any case 

 it was greatest in the case of a 678 m|i interference filter which 

 had an infra-red transmission band as well. 



