Deposition at cryogenic temperatures is generally considered to be the safest method for long-term storage of living materials. (For a general introduction into the storage of plant cell cultures, refer to Chapter 11.
The kinetics of T1 absorption by excised barley roots were studied with respect to the time and concentration dependence, sensitivity to Ca, and interaction with Rb and Na. The following conclusions were drawn: T1 is bound by sites normally binding K. In the range of concentrations from 0 to 0.2 me/l, T1 is absorbed readily into the protoplasm but vacuolar accumulation is slow and tends to stagnate. Although O2 uptake is progressively reduced in the presence of T1, this effect does not seem responsible for the stagnation of vacuolar absorption. Besides a competitive inhibition, there is a stimulation of vacuolar T1 transport by Rb but not by Na. The peculiarities of T1 absorption are tentatively explained on the basis of structural interactions between a macromolecular carrier and the ions transported.
