Acclimation of potassium influx in rye (Secale cereale) to low root temperatures
✍ Scribed by P. J. White; D. T. Clarkson; M. J. Earnshaw
- Publisher
- Springer-Verlag
- Year
- 1987
- Tongue
- English
- Weight
- 865 KB
- Volume
- 171
- Category
- Article
- ISSN
- 0032-0935
No coin nor oath required. For personal study only.
✦ Synopsis
The influx of K+(86Rb +) into intact roots of rye (Secale cereale L. cv. Rheidal) exposed to a differential temperature (DT) between the root (8 ~ C) and shoot (20 ~ C) is initially reduced compared with warm-grown (WG) controls with both shoot and root maintained at 20 ~ C. Over a period of 3 d, however, K+-influx rates into DT plants are restored to levels similar to or greater than those of the WG controls, the absolute rates of K + influx being strongly dependent upon the shoot/root ratio. Acclimation in DT plants results in a reduction of K + influx into the apical (0-2 cm) region of the seminal root which is associated with a compensatory increase in K + influx into the more mature, basal regions of the root. Values of Vmax and apparent Km for K + influx into DT plants were similar to those for WG plants at assay temperatures of 8 ~ C and 20 ~ C except for an increase in the apparent Km at 8 ~ C. The influx of K + from solutions containing 0.6 mol.m 3 K + into both WG and DT plants was found to be linearly related to assay temperature over the range 2-27 ~ C, and the temperature sensitivity of K + influx to be dependent upon shoot/root ratio. At high shoot/root ratios, the ratio of K + influx at 20 ~ + influx at 8~ for WG plants approached a minimum value of 1.9 whereas that for DT plants approached unity indicating that K + influx into DT plants has a large temperatureinsensitive component. Additionally, when plants