I’m working on nutrient uptake during mycorhization (symbiotic interaction). The cortical cells are colonized by the fungus, at this level occur the exchanges between the two symbionts ... So, during mycrhization the uptake and transportation of nutrition in saline stress condition (or other biotic and abiotic stress) is modified, the plants are more resistant.
I never heard about specific cell line naturally present on plant roots which can modulate the uptake during a stress, but in general, the plants can over or down express some nutrient transporters (ammonium, phosphate …)
There are surely certain nutrient transporters lying embedded in the plasmalemma of root cells , the density of which decides the accumulation or exclusion behaviour of roots..