Root tips of the wilty pepper mutant scarbrous diminutive accumulate less rubidium than those of the normal genotype. This phenomenon was evident in root tips excised from plants maintained for 2 d in CaSO4 solution (low salt plants), especially in the lower external concentration range (0.1- 1.0 mM) of RbCl. The efflux rate of Rb+ from mutant root tips was twice as high as in normal root tips.These results indicate that the ability of the mutant roots to absorb and accumulate Rb+ and K+ is impaired. This defect could be a consequence of either an impaired Na+/K+ carrier system, or increased leakiness of mutant membranes, or both.The fact that the normal roots can accumulate Rb+ much faster than mutant roots supports the first alternative, i.e. that the high affinity carrier system was impaired in the mutant roots. However, the higher efflux rate of Rb+ from the mutant roots suggests that membrane leakiness was also affected.
ASJC Scopus subject areas
- Plant Science