Table I.

Effects of Al³⁺, Ca²⁺, and Mg²⁺ on root elongation in cv Scout 66 seedlings

AlCl3	CaCl2	MgCl2	Measured RRLmax	A1	A2	Computed RRLmax
μm
0	10	990	54	1	0.56	56
0	20	980	60	1	0.70	70
0	40	960	85	1	0.82	82
0	80	920	95	1	0.91	91
0	160	840	93	1	0.97	97
0	320	680	100	1	0.99	99
2	10	990	24	0.60	0.42	25
2	20	980	29	0.60	0.55	32
2	40	960	47	0.60	0.68	40
2	80	920	70	0.60	0.78	48
2	160	840	58	0.60	0.90	54
2	320	680	65	0.60	0.96	57
3	10	990	16	0.47	0.39	18
3	20	980	41	0.47	0.51	24
3	40	960	33	0.47	0.64	30
3	80	920	42	0.47	0.77	36
3	160	840	41	0.47	0.88	41
3	320	680	41	0.47	0.95	45
4	10	990	11	0.38	0.37	14
4	20	980	21	0.38	0.49	19
4	40	960	28	0.38	0.62	24
4	80	920	28	0.38	0.75	29
4	160	840	34	0.38	0.86	33
4	320	680	25	0.38	0.94	36

Each solution was adjusted to pH 4.6 with HCl. RL_max = 75.5 mm and RL_S = 34.0 mm. Two of the column headings are terms taken from Equation 3; A₁ = 1/exp[(a₁{T}₀)^{b₁] and A₂ = 1 − 1/exp[(a₂{Ca2+}₀)b₂]. The computed RRL_max = 100 A₁ · A₂. The data are from a single experiment representative of several similar but not identical Al3+-Ca2+-Mg2+ experiments; the coefficients for the computation of RRL_max are based on 57 measurements (see Table II).}