Aluminium is essential for root growth and development of tea plants (Camellia sinensis)

On acid soils, the trivalent aluminium ion (Al(3+)) predominates and is very rhizotoxic to most plant species. For some native plant species adapted to acid soils including tea (Camellia sinensis), Al(3+) has been regarded as a beneficial mineral element. In this study, we discovered that Al(3+) is actually essential for tea root growth and development in all the tested varieties. Aluminum ion promoted new root growth in five representative tea varieties with dose‐dependent responses to Al(3+) availability. In the absence of Al(3+), the tea plants failed to generate new roots, and the root tips were damaged within 1 d of Al deprivation. Structural analysis of root tips demonstrated that Al was required for root meristem development and activity. In situ morin staining of Al(3+) in roots revealed that Al mainly localized to nuclei in root meristem cells, but then gradually moved to the cytosol when Al(3+) was subsequently withdrawn. This movement of Al(3+) from nuclei to cytosols was accompanied by exacerbated DNA damage, which suggests that the nuclear‐targeted Al primarily acts to maintain DNA integrity. Taken together, these results provide novel evidence that Al(3+) is essential for root growth in tea plants through maintenance of DNA integrity in meristematic cells.