Ytterbium increases transmembrane water transport in Zea mays roots via aquaporin modulation

In our study, the rare earth element ytterbium (Yb 3+ ) was demonstrated to affect water exchange in roots of Zea mays seedlings. Herewith, the overall membrane permeability (P d ) increased. The P d increase was determined by aquaporin activity but not the membrane lipid component since the closure of aquaporin channels due to low intracellular pH abolished the positive effect of Yb 3+ on P d . Additionally, the expression level of aquaporin genes ZmPIP2;2, ZmPIP2;6 and ZmTIP2;2 was increased when plants were grown in the presence of Yb 3+ . Our results indicate that previously described positive influence of rare earth metals on plant growth and productivity may be mediated (at least partially) by the modification of the plant hydraulic system.