SUMMARY 131 



Summary 



Hydrilla plants, under seasonal variation of summer 

 with its prevailing high temperature, become acid. Photo- 

 synthesis, as evidenced by evolution of oxygen, is then found 

 to take place in the complete absence of supply of carbon 

 dioxide. 



The photosynthetic curve of acid Hydrilla plants 

 exhibits a variation from the normal, the characteristic 

 points of the curve being transposed towards the origin. 

 This indicates that the organic acids present in the plant 

 were assimilated in lieu of carbon dioxide. 



The electric response of the markedly acid plant Cicer 

 arietinum is positive, which is indicative of anabolic 

 activity. This characteristic positive response takes place 

 even in the absence of carbon dioxide. 



Since, in the photosynthesis of acid plants, the organic 

 acids can replace carbon dioxide, the absorption of C0 2 by 

 these plants is less than normal. Hence the assimilatory 



quotient ^y i n ac id plants is greater than unity, while the 



respiratory quotient is less. 



The photosynthetic curve with increasing strengths of 

 malic acid exhibits a remarkable similarity to that with 

 increasing C0 2 -concentrations. 



The acidity of the plant disappears during the rainy 

 season, when photosynthesis is found to return to the normal. 



It is highly probable that plants utilise for assimila- 

 tion the carbon dioxide produced in their own internal 

 respiration. 



