TY  - JOUR
A1  - Schmalzlin, E.
A1  - van Dongen, J. T.
A1  - Klimant, I.
A1  - Marmodee, Bettina
A1  - Steup, Martin
A1  - Fisahn, Joachim
A1  - Geigenberger, Peter Ludwig
A1  - Löhmannsröben, Hans-Gerd
T1  - An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants
N2  - A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen- sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong auto fluorescence of the plant tissue. The method was established using photosynthesis- competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species
Y1  - 2005
SN  - 0006-3495
ER  - 
TY  - JOUR
A1  - Gajdanowicz, Pawel
A1  - Michard, Erwan
A1  - Sandmann, Michael
A1  - Rocha, Marcio
A1  - Correa, Luiz Gustavo Guedes
A1  - Ramirez-Aguilar, Santiago J.
A1  - Gomez-Porras, Judith L.
A1  - Gonzalez, Wendy
A1  - Thibaud, Jean-Baptiste
A1  - van Dongen, Joost T.
A1  - Dreyer, Ingo
T1  - Potassium (K plus ) gradients serve as a mobile energy source in plant vascular tissues
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - The essential mineral nutrient potassium (K(+)) is the most important inorganic cation for plants and is recognized as a limiting factor for crop yield and quality. Nonetheless, it is only partially understood how K(+) contributes to plant productivity. K(+) is used as a major active solute to maintain turgor and to drive irreversible and reversible changes in cell volume. K(+) also plays an important role in numerous metabolic processes, for example, by serving as an essential cofactor of enzymes. Here, we provide evidence for an additional, previously unrecognized role of K(+) in plant growth. By combining diverse experimental approaches with computational cell simulation, we show that K(+) circulating in the phloem serves as a decentralized energy storage that can be used to overcome local energy limitations. Posttranslational modification of the phloem-expressed Arabidopsis K(+) channel AKT2 taps this "potassium battery," which then efficiently assists the plasma membrane H(+)-ATPase in energizing the transmembrane phloem (re) loading processes.
KW  - channel gating
KW  - energy limiting condition
KW  - phloem reloading
KW  - posttranslational regulation
KW  - potassium channel
Y1  - 2011
U6  - https://doi.org/10.1073/pnas.1009777108
SN  - 0027-8424
VL  - 108
IS  - 2
SP  - 864
EP  - 869
PB  - National Acad. of Sciences
CY  - Washington
ER  -