T. C. Broyer 229 



solute activity.* The required energy expenditure is possibly related 

 to the oxidative formation of high energy specific protoplasmic con- 

 stituents, or special configurations thereof, in which form they interact 

 with inorganic solute ions at outer loci within the protoplasm. Through 

 this association, the activity of the solute constituent is effectively 

 lowered from that in the external medium. The nature of the binding 

 is a moot question. Whether secretion is then involved as one step 

 from protoplasm to lumen is debatable. It seems more reasonable to 

 the writer to postulate that the higher solute activity is resident within 

 the intermicellar fluid of the inner regions of protoplasm, the inward 

 flux therefrom to the lumen occurring with the direction in which the 

 effective concentration of the individual solute constituent decreases. 

 Rather then, subsequent translocation of the complex (by diffusion 

 and/or protoplasmic streaming) to loci more internal within the 

 protoplasm, where conditions and rates of related processes differ from 

 those existing nearer the exterior surface, may there involve the rupture 

 of the solute-protoplasmic union through reduction, rearrangement, or 

 deformation of the protoplasmic constituents resulting in the release of 

 the accompanying inorganic member to the intermicellar fluid of the 

 colloidal system. Concurrently, the protoplasmic constituent of the 

 complex is transformed from a higher energy content to one of lower 

 energy, the energy being transferred to the solute constituent associated 

 with its higher activity, where compared with that in the external phase. 

 Thus, in brief, the solute migrates from regions of protoplasm where 

 the ability to hold solute constituents is great to regions where the 

 retention is critically lessened, concomitant with a gradient of de- 

 creasing oxidative metabolism (21). The polarized flux of solute, there- 

 fore, parallels specific protoplasmic connection and disconnection with 

 solute constituents characteristically accumulated by the particular plant 

 in accord with its genetic constitution. The energy expended toward 

 the configuration or formation of the protoplasmic cycle is transferred 

 in essence to the solute as a net result with an increase of the internal 

 solute activity by means of this intermediate interaction between 



* Rates of concurrent diffusion and/or exchange adsorption are limited by the 

 permeability of the interposed protoplasm and the activity or concentration 

 gradient (cf. Dean and Overstreet in this book) of the solute constituents. 



