Transmembrane calcium fluxes during Al stress

The primary Al lesion is suggested to be blockage of the root plasma membrane Ca²⁺ channels. Resulting decrease in net Ca²⁺ uptake into the root tip cells leads to Ca²⁺ deficiency in the cytoplasm and disturbance of the cell Ca²⁺ homeostasis, effects that can deleteriously influence cell structure and function. Contribution of internal Ca²⁺ stores to maintaining cytoplasmic Ca²⁺ concentration at physiological levels is considered to be insufficient in meristematic cells at the root tip. It is suggested that differential blockage of Ca²⁺ channels may be at the core of differential tolerance to Al, opening up the possibility of manipulating Al tolerance at the molecular level.