9 6 



CHAP. XII. EFFECT OF INTERMITTENT LIGHT 



longer intermission-periods, the molecular recovery causes 

 increasing retardation till the turning-point is reached. The 

 curve of photosynthetic efficiency thus exhibits three 

 phases : the enhanced efficiency under short intermission 



Period of Intermission 



. Fig. 28. Curve showing Variation of Photosynthetic Efficiency 

 at various rates of Intermission of Light 



Note enhancement of efficiency in the first stage, lowered 

 efficiency in the second stage, and partial recovery in the third 

 stage. 



in the first stage, passing through the point of neutralisa- 

 tion to the second stage of decreasing efficiency under 

 increasing periods of intermission, reaching the turning- 

 point ; after this at the third stage there is an exhibition of 

 partial recovery. 



