CONTENTS XV 



CHAPTER XXII 



DETERMINATION OF PHOTOSYNTHETIC EFFICIENCY 

 OF THE SPECTRAL RAYS 



PAGE 



Difficulties in the quantitative determination of photosynthesis 

 under enfeebled spectral rays — Results with exceptionally 

 sensitive specimens — Enhancement of sensitiveness by rise of 

 temperature — Vacuum-jacket for maintenance of constant 

 temperature — Method of depletion of starch in enhancement of 

 sensitiveness — The Heterostatic Method — The Auxiliary Stimu- 

 lator—Additive effect of light— The Absorption-Spectrum— 

 Tropic movement under certain rays of the spectrum — Simul- 

 taneous determination of energy of rays and of the induced 

 photosynthesis— Characteristic effects of different rays on 

 photosynthesis — Complementary relation of A and D effects in 

 photosynthesis and in phototropism . . • • .185 



CHAPTER XXIII 



DETERMINATION OF THE INCREASE OF WEIGHT 

 DUE TO PHOTOSYNTHESIS 



Errors in determination of photosynthetic increase of weight by the 

 half-leaf method — Indirect determination from absorption of 

 carbon dioxide — Indefinite value of the carbohydrate-factor — 

 Necessary conditions for accurate results — Direct determination of 

 the increase of weight of the living plant due to photosynthesis 

 — Theory of the method — Advantages of the new method — 

 Torsion Balance for determining increase of weight — Determina- 

 tion by Chemical Balance — Determination of photosynthesis 

 under diffused light and under sunlight— Maximum rate of 

 formation of carbohydrate per unit area . . . • .198 



CHAPTER XXIV 



SIMULTANEOUS DETERMINATION OF CARBOHYDRATE- 

 FORMATION BY TWO INDEPENDENT METHODS 



Direct and indirect estimation of photosynthetic production of 

 carbohydrate — Indirect methods based on absorption of carbon 

 dioxide and on the evolution of oxygen — Oxygen-carbohydrate 

 factor — Indirect determination of increase of weight from 

 volume of evolved oxygen — Direct determination by weighing 

 the plant before and after exposure to light — Simultaneous 

 determination of carbohydrate by direct and indirect methods — 



