CONTENTS Xlll 



PAGE 



synthetic curve for CCyvariation — The turning-point — Deter- 

 mination of the photosynthetic coefficient — Effect of seasonal 

 variation on coefficient . . . . . . . .113 



CHAPTER XVI 



PHOTOSYNTHETIC EVOLUTION OF OXYGEN IN THE 

 COMPLETE ABSENCE OF CARBON DIOXIDE 



Photosynthetic evolution of oxygen by Hydrilla in complete absence 

 of supply of carbon dioxide — Photosynthesis of specimens in acid 

 condition under increasing supply of carbon dioxide — Transloca- 

 tion of the characteristic points in photosynthetic curve — Electric 

 response of acid plants — Unreliability of method of C0 2 -absorp- 

 tion — Assimilatory and respiratory quotients — Assimilation of 

 organic acids — Effect of increasing strengths of malic acid on 

 photosynthesis — Possible use of product of internal respiration 

 in photosynthesis . . . . . . . . .122 



CHAPTER XVII 



EFFECT OF VARIATION OF TEMPERATURE 

 ON PHOTOSYNTHESIS 



Determination of the respiratory loss — Importance of accurate 

 adjustment of temperature — Shock-effect caused by sudden 

 variation — Determination of thermometric minimum for photo- 

 synthesis — Phenomenon of accommodation — Thermometric 

 minimum for autonomous pulsation — Determination of the 

 optimum point for photosynthesis — Effect of intensity of light 

 and of season — Photosynthetic curve under variation of tem- 

 perature — Optimum point for various activities of plants — 

 Determination of the temperature-coefficient of photosynthesis 

 by the differential method . . . . . . .132 



CHAPTER XVIII 



THE TONIC FACTOR IN PHOTOSYNTHESIS 



The effect of season on physiological activity — The tonic level — The 

 Tonometer — Measurement of tonicity from the ratio of response 

 to stimulus — Effect of season on photosynthesis — Induced change 

 of the tonic level under seasonal variation — Effect of minute 

 traces of chemical substances in modifying tonic condition — 



