Table I.

Published ζ potentials of plant protoplasts or PM vesicles in various media compared with calculated surface potentials

Species and Ref.	Solution No.	pH	CaCl2	MgSO4	NaCl	KCl	LaCl3	ζ Potential	ψ0,Y	ψ0,A
			mm					mV
Barley leaf protoplasts (Abe and Takeda, 1988)
	1	6.7	0.1		0.5			−48	−66	−65
	2	6.7	0.1		6.5			−39	−59	−58
	3	6.7	0.1		0.5	6.0		−39	−59	−58
	4	6.7	0.1		0.5		0.1	−17	−7	−6
	5	6.7	0.1		0.5		0.3	0	+2	+3
	6	6.7	0.1		0.5		1	+14	+12	+13
	7	3.6	0.1		6			−2	−14	+5
	8	3.6	0.1				1	+23	+10	+17
Barley leaf protoplasts (Obi et al., 1989a)
	9	7.6			3			−29	−100	−100
	10	7.6			7.5			−20	−82	−82
	11	7.6			15			−13	−67	−66
	12	7.6			1	14		−13	−67	−66
	13	7.6			30			−10	−52	−51
	14	7.6	1		4.5			−10	−36	−36
	15	7.6		1a	4.5			−11	−36	−36
	16	7.2			0.5		0.17	0	−2	−2
	17	6.5			5		1	+3	+12	+12
Corn root PM vesicles (Gibrat et al., 1985)
	18	6.5			15			−24	−64	−64
	19	6.5			65			−14	−36	−36
	20	6.5		6	15			−8	−16	−15
	21	6.5		6	65			−6	−13	−12
Tobacco leaf protoplasts (Nagata and Melchers, 1978)
	22	5.8			6.7	10		−28	−56	−55
	23	5.8	1		6.7	10		−25	−32	−32
	24	5.8	10		6.7	10		−9	−10	−9
	25	5.8	100		6.7	10		0	+7	+8
Rauwolfia serpentina cultured cell protoplasts (Obi et al., 1989b)
	26	7.3	0.02		6	1		−18	−72	−71
	27	6.3	0.02		6	1		−18	−69	−69
	28	5.3	0.02		6	1		−17	−56	−54
	29	4.2	0.02		6	1		−12	−27	−18
	30	3.0	0.02		6	1		+2	−5	+29
Barley leaf protoplasts (Obi et al., 1990)
	31	7.3	0.02		6	1		−18	−72	−71
	32	6.3	0.02		6	1		−16	−69	−69
	33	5.2	0.02		6	1		−12	−54	−51
	34	4.0	0.02		6	1		+1	−22	−10
	35	2.7	0.02		6	1		+18	−2	+40

ψ_0,Y is the potential computed by the model of Yermiyahu et al. (1997c) and ψ_0,A is the potential computed by the adjusted model of the present study. For each of the two models, a single set of parameter values was used throughout. The column designated NaCl includes NaCl plus any monovalent buffer ions.

^aMgCl₂.