ABSTRACT
In our study, the rare earth element ytterbium (Yb3+) was demonstrated to affect water exchange in roots of Zea mays seedlings. Herewith, the overall membrane permeability (Pd) increased. The Pd 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 Yb3+ on Pd. Additionally, the expression level of aquaporin genes ZmPIP2;2, ZmPIP2;6 and ZmTIP2;2 was increased when plants were grown in the presence of Yb3+. 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.
Subject(s)
Aquaporins/metabolism , Cell Membrane/drug effects , Plant Roots/drug effects , Water/metabolism , Ytterbium/pharmacology , Zea mays/drug effects , Cell Membrane/metabolism , Cell Membrane Permeability/drug effects , Hydrogen-Ion Concentration , Plant Roots/metabolism , Proton Magnetic Resonance Spectroscopy , Seeds/drug effects , Seeds/growth & development , Seeds/metabolism , Water/chemistry , Ytterbium/chemistry , Zea mays/growth & development , Zea mays/metabolismABSTRACT
Changes of diffusive permeability of membranes of Elodea nuttallii cells following a short-term (60 min) treatment with high concentrations of lanthanides were recorded by the 1H NMR-diffusometry and conductometry methods. The 1-h infiltration of segments of Elodea nuttallii internodes in 10 mM solutions of nitrates of La, Nd and Lu resulted in the increased leakage of electrolytes from cells, but has no effect on a water diffusive permeability of membranes. In samples subjected to a 30 min pretreatment with a water channel inhibitor HgCl2 the water diffusive permeability of membranes (Pd) drops down under the influence of lanthanides, as well as an outcome of electrolytes. To explain the observed effects the change of spontaneous curvature of membrane lipid layer has been taken into consideration. The interaction of lanthanides with lipids of plasmalemma leads to the negative spontaneous curvature of lipid layer at which membrane channels are unclosed. Blocking of the ionic and water channels by mercury ions compensate the effect of change of spontaneous curvature of lipid layer.
Subject(s)
Aquaporins/metabolism , Fresh Water/chemistry , Hydrocharitaceae/drug effects , Lanthanoid Series Elements/analysis , Water Pollutants, Chemical/analysis , Cell Membrane/drug effects , Cell Membrane/metabolism , Cell Wall/drug effects , Cell Wall/metabolism , Hydrocharitaceae/cytology , Hydrocharitaceae/metabolism , Ion Exchange , Lanthanoid Series Elements/metabolism , Lanthanoid Series Elements/toxicity , Permeability , Water Pollutants, Chemical/metabolism , Water Pollutants, Chemical/toxicityABSTRACT
The translational displacement of the cytoplasmic water in Elodea stem cells resulting from protein motor activity was measured using the NMR method. A 24-h treatment with vincristine results in a reduction of the translational displacement of the cytoplasmic water. With a constant cytoplasmic streaming velocity, the dynamics of the translational displacement of the cytoplasmic water under the effect of taxol are characterized by a continuous increase at a concentration of 0.05 mM, and reaching a plateau at a concentration of 0.5 mM.
