Chemical Organization of a Typical Fruit. 



21 



These results show rapid inversion of the cane sugar after 

 the fruit has been crushed during the short time taken to press 

 the pulp. The total quantity of sugar in the juice which flows 

 off by gravity and in the portion obtained under the highest 

 pressure is practically identical. The soluble nitrogenous matter, 

 however, increases greatly under increased pressure but is not 

 accompanied by invertase, excepting in the portion obtained 

 under low pressure, and in this case by only a small amount 

 which appears to be in suspension only. Thus it is evident that 

 in the uninjured green fruit the cell contents are so ordered that 

 contact between invertase and cane sugar takes place but very 

 slowly; that this intracellular invertase is not in solution and re- 

 tained by the impermeability of the plasmic cell wall, but is 

 held in an insoluble form probably in the protoplasm. Un- 

 doubtedly other enzymes involved in the ripening processes are 

 similarly held, in which case absolutely no reaction could take 

 place between them and other insoluble cell constituents. Upon 

 the death of the protoplasm by poisoning with various chemicals 

 or by the heat the green date ripens prematurely which, judging 

 from the invertase relations is due to the solution of these hitherto 

 insoluble enzymes. If the green date tissue is killed by grinding, 

 washing with watei and drying these same means no longer 

 suffice to liberate the invertase; it remains permanently insoluble 

 but active. 



Arizona Agricultural 

 Experiment Station, 



