Figure 7.

Dependence of R-induced protoplast swelling on K⁺, Cl⁻, and H⁺ of the bathing medium. Protoplasts isolated from peeled stems of pea cv Alaska seedlings were washed with and suspended in the standard medium (A; see Fig. 1 for the compositions), a medium in which K⁺ was replaced by TEA⁺ (B), a medium in which Cl⁻ was replaced by IDA (C), and a medium adjusted to pH 7.0 (D). The protoplasts were incubated under background R as described for Figure 1 and were subjected to time-lapse photography from time zero, which was 25 min after the onset of incubation. After obtaining a photograph at 20 min, protoplasts were washed with and resuspended in the standard medium, incubated again under background R, and subjected to time-lapse photography. The dashed vertical line indicates the time at which the protoplasts were suspended in a large volume of the standard medium (the first step of protoplast washing). The volume of each protoplast was calculated as a percentage of the initial volume before or after the washing treatment. The means ± se from 19 to 23 protoplasts are shown.