Kinetic Studies of Anion Absorption by Potato Slices at 0 C

摘要: Generally speaking, the time course of ion uptake by plant tissue is characterised two distinct phases, a relatively short initial period rapid followed less but prolonged absorption. Frequently this basic absorption pattern still holds after discounting ions present in water free space (WFS), i.e., that part apparent (AFS) which effect an extension medium. The term, AFS, refers to fraction volume into external solution appears diffuse readily and equals sum WFS, both permeating salt are freely diffusible, DFS (mostly cations) held exchangeable form fixed charges tissue. With cation shoulder can be attributed adsorption exchange on negative groups (mainly carboxyl groups) cell wall (See Laties, 8). A two-component anion observed more difficult interpret. Since with its associated predominantly negatively charged, surfaces thought negligible, i.e. when using mobile anions assumes zero value. Even so has been wheat roots potato disks Lundegardh (10, 11, 12), who sites, Laties (9), suggested represented latent carrier potential attending transfer slices from room temperature 0 C. rationale offered was concentration (using term operational sense) at any given moment function temperature, level characteristic steady state 25 C measureably higher than C, transferring there transistory excess for leads initially. reported 12) ambiguous nature. In some experiments technique involved switch lower it may well most his shoulders attributable fact measured determining remaining experimental solution, and, therefore, values would include uptake, since pre-absorption rinse test only seconds duration (10) not fill space. That were under metabolic control seem borne out they varied magnitude almost linearly yielding unreasonably high independent species. Only cyanide results variance interpretation their significance cannot assessed without clearer understanding separate effects AFS penetration phase I uptake. however, directly related lowering thus, represents special phenomenon particular interest conceivably illumine aspect relating mechanism or geometry detectable otherwise. This study attempt characterise further determine whether as manifested specific respect presumed transported different carriers utilize transport capacity mutually exclusive manner.