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Journal of Experimental Biology 11,103-119 (1934)
Published by Company of Biologists 1934

The Absorption and Accumulation of Solutes by Living Plant Cells : VII. The Time Factor in the Respiration and Salt Absorption of Jerusalem Artichoke Tissue (Helianthus Tuberosus), with Observations on Ionic Interchange

F. C. STEWARD ¹ and W. E. BERRY ¹

¹ Department of Botany, University of Leeds

1. The rapid decline in the respiration (CO₂ production) of immersed, aerated artichoke discs is confirmed.

2. The decreasing respiration is not associated with any known external factor.

3. Dilute potassium bromide solutions cause a temporary, increased respiration which quickly disappears after 24 hours. This effect appears at various points on the respiration/time curve.

4. By the technique used, washed, blotted artichoke discs immediately after reimmersion release electrolytes to both distilled water and dilute salt solutions but re-absorption, which very rapidly supervenes, is extensive after 18 hours and is complete after 48 hours.

5. Decreasing respiration is accompanied by a decreasing ability to absorb inorganic ions (KBr). The reductions with time of total respiration and salt absorption are similar but not identical.

6. Absorption of potassium bromide from the external solution is accompanied by a decrease of conductivity in the outer solution and an increase in that of the expressed sap. During short periods (24 hours) it appears that the mechanism of ionic exchange can only play a minor rôle. Bromide does not replace chloride. Apparently potassium and bromide are simultaneously accumulated.

7. Apparent irregularities in the first period may be satisfactorily explained.

8. Some factor associated with long, continuous contact of artichoke tissue with dilute bromide solutions tends to reduce absorption compared with a series of short periods. This may be due to accumulation in the earlier periods which reduces absorption in the later ones or may admit of an explanation based upon the transient effect of addition of bromide.

9. The general relation between salt absorption and respiration for artichoke is established. An indirect role is preferred to a direct one. Respiration is assumed to maintain vital metabolic processes which supply the energy necessary for an absorption process in which work must be done.