Claim · model-written summary
The decrease in rate per unit area is attributed to a decrease in protein per unit area.
Zea maysVerbatim
e0“along the course of maize roots”
e5“This is attributed to an increasing protein content, and the decrease in rate per unit area to a corresponding decrease in protein per unit area”
Title
The Absorption of Potassium by Cells in the Apex of the Root
R. BROWN; P. M. CARTWRIGHT Journal of Experimental Botany 1953. doi:10.1093/jxb/4.2.197
Other claims from this paper (17)
- Observation Potassium absorption by the first, almost entirely meristematic root section is abnormally low.
- Mechanism The low absorption of the first root section is attributed to the absence of a tonoplast around a central vacuole.
- Association The rate per unit area of surface decreases as cells expand after vacuolation in the root.
- Association Per cell, potassium absorption increases as expansion occurs in the root.
- Mechanism Per-cell absorption increase is attributed to increasing protein content.
- Observation Absorption per unit protein increases during cell growth in the root as cytoplasm differentiates.
- Observation After excision, protein content does not increase whether or not growth occurs.
- Observation Final internal potassium concentrations in the sections vary according to the growth that occurs.
- Observation After vacuolation with limited growth, the final internal concentration is greater than at the beginning of the experiment.
- Observation When growth occurs, the final internal concentration may be lower.
- Mechanism Absorption depends on an inward secretion into the vacuole that is independent of surface area.
- Mechanism Absorption includes an outward diffusion into the medium that increases with surface area.
- Intervention effect Sugar stimulates the rate of potassium absorption.
- Intervention effect When growth does not occur, sugar enhances the final internal concentration.
- Intervention effect When growth occurs, sugar stimulates potassium absorption.
- Intervention effect When growth occurs, sugar stimulates expansion of the cell.
- Intervention effect The expansion effect of sugar may lead to a final concentration lower than without sugar.
Zea mays subsp. mays
Avena sativa.jpg?width=60){kind=small}
Hordeum vulgare
Sorghum bicolor
Triticum aestivum