Table I. Elemental concentrations in shoots of Arabidopsis plants grown on various concentrations of heavy metals.

Seedlings were precultured in one-half-strength MS medium for 7 d and then transferred to one-half-strength MS medium (control) or one-half-strength MS medium supplemented with the indicated concentrations of metals for 9 d. Values represent means ± sd. Different letters indicate statistically significant differences among means for each heavy metal (P < 0.05, Tukey’s test); n.d., not detected. Boldface values are significantly lower than those measured in Fe-supplemented control plants. Values for Ca, K, Mg, P, and S are in mg g⁻¹, and those for Fe, Cd, Co, Mn, Ni, and Zn in µg g⁻¹.

Treatment		Ca	K	Mg	P	S	Fe	Cd	Co	Mn	Ni	Zn
	µm
Fe	75	5.8 ± 0.4 b	53.5 ± 3.2 b	1.8 ± 0.1 b	15.7 ± 1.3 a	8.2 ± 0.4 a	89.7 ± 6.6 a	n.d.	n.d.	213 ± 14.4 b	n.d.	162 ± 15.0 b
	0a	9.9 ± 1.6 a	60.7 ± 8.3 a	2.7 ± 0.5 a	15.9 ± 2.2 a	21.3 ± 3.6 b	19.3 ± 10.7 b	n.d.	n.d.	456 ± 52.3 a	n.d.	1,006 ± 234.3 a
Zn	18	5.1 ± 0.7 b	54.1 ± 3.8 b	1.4 ± 0.1 ab	14.3 ± 1.1 a	8.6 ± 0.6 b	89.7 ± 6.6 a	n.d.	n.d.	199 ± 11.2 b	n.d.	157 ± 9.3 d
	75	6.1 ± 0.4 a	63.1 ± 4.4 a	1.5 ± 0.1 a	14.8 ± 1.9 a	13.5 ± 1.7 ab	65.9 ± 11.3 b	n.d.	n.d.	220 ± 16.8 a	n.d.	641 ± 160.7 c
	150	6.0 ± 0.8 a	56.2 ± 5.1 b	1.5 ± 0.1 ab	13.8 ± 1.3 a	17.1 ± 1.4 a	54.3 ± 22.3 b	n.d.	n.d.	184 ± 20.0 b	n.d.	1,060 ± 90.7 b
	225	5.1 ± 0.4 b	52.7 ± 5.4 b	1.3 ± 0.1 b	12.8 ± 1.7 a	16.6 ± 1.3 a	63.4 ± 17.7 b	n.d.	n.d.	158 ± 14.9 c	n.d.	1,325 ± 81.9 a
Co	0.05	4.0 ± 6.3 b	51.9 ± 4.2 a	1.6 ± 0.1 b	13.3 ± 1.3 a	10.0 ± 0.6 c	89.7 ± 6.6 a	n.d.	n.d. d	191 ± 14.9 a	n.d.	161 ± 33.7 a
	50	4.9 ± 5.5 a	49.3 ± 3.5 ab	1.8 ± 0.1 a	12.9 ± 1.3 ab	15.2 ± 0.7 a	82.2 ± 5.4 a	n.d.	197 ± 18.9 c	210 ± 17.0 a	n.d.	116 ± 26.8 b
	90	4.6 ± 2.0 a,b	45.9 ± 2.2 b	1.6 ± 01. a,b	11.5 ± 1.2 b,c	14.6 ± 0.9 a,b	56.8 ± 14.8 b	n.d.	328 ± 23.8 b	208 ± 10.1 a	n.d.	111 ± 2.1 b
	110	3.9 ± 4.9 b	45.4 ± 1.4 b	1.5 ± 0.1 b	10.9 ± 1.0 c	13.7 ± 0.6 b	58.0 ± 9.7 b	n.d.	406.9 ± 30.9 a	201 ± 12.3 a	n.d.	113 ± 5.6 a,b
Ni	0	2.7 ± 0.3 b	49.9 ± 3.8 b	1.3 ± 0.1 a	12.0 ± 1.2 a	8.0 ± 0.5 b	89.7 ± 6.6 a	n.d.	n.d.	166 ± 15.3 b	n.d. d	169 ± 24.2 c
	60	3.4 ± 0.5 a	58.3 ± 7.8 a,b	1.1 ± 0.1 a,b,c	13.5 ± 1.6 a	11.2 ± 1.8 a	75.6 ± 8.6 ab	n.d.	n.d.	225 ± 34.0 a	80 ± 13.7 c	330 ± 50.4 a
	100	2.4 ± 0.3 b	55.0 ± 2.5 a	1.1 ± 0.1 b	9.4 ± 0.9 b	9.7 ± 0.7 a	71.2 ± 6.8 b,c	n.d.	n.d.	146 ± 12.1 b	140 ± 16.9 b	245 ± 16.9 b
	150	3.1 ± 0.4 a	39.6 ± 3.3 c	1.0 ± 0.1 c	7.4 ± 0.8 b	8.7 ± 1.4 a	49.9 ± 12.2 c	n.d.	n.d.	118 ± 11.8 b	296 ± 36.2 a	192 ± 37.4 b
Cd	0	5.0 ± 0.3 b	50.0 ± 1.8 b	1.6 ± 0.1 c	14.2 ± 0.9 c	8.4 ± 0.5 c	89.7 ± 6.6 a	n.d. c	n.d.	211 ± 15.0 b	n.d.	169 ± 23.2 a
	5	7.8 ± 0.6 a	68.8 ± 4.9 a	2.2 ± 0.1 a	20.4 ± 2.0 a	18.3 ± 2.2 b	61.0 ± 8.9 b	200 ± 35.7 b	n.d.	235 ± 13.8 a	n.d.	165 ± 16.4 a
	20	4.3 ± 0.4 b	58.4 ± 5.0 ab	1.8 ± 0.2 b	16.8 ± 1.1 b	24.2 ± 2.4 a	65.2 ± 12.5 b	238 ± 30.0 a,b	n.d.	139 ± 13.7 c	n.d.	149 ± 38.4 ab
	40	3.3 ± 0.3 c	52.3 ± 2.4 b	1.6 ± 0.1 b,c	16.2 ± 1.1 b	21.3 ± 1.5 a,b	66.3 ± 18.4b	280 ± 15.7 a	n.d.	118 ± 13.5 c	n.d.	118 ± 10.5 b
Mn	40	3.2 ± 0.1 b	46.1 ± 2.2 a	1.2 ± 0.05 a	8.7 ± 0.3 a	6.4 ± 0.3 c	89.7 ± 6.6 a	n.d.	n.d.	143 ± 8.7 c	n.d.	128 ± 23.4 b
	1,000	2.1 ± 0.3 b	48.4 ± 6.0 a	0.6 ± 0.05 b	8.8 ± 1.3 a	10.1 ± 0.9 a	83.8 ± 12.7 a	n.d.	n.d.	2,261 ± 286.4 b	n.d.	228 ± 18.4 a
	1,250	2.7 ± 0.8 b	51.7 ± 6.7 a	0.6 ± 0.2 b,c	6.1 ± 0.6 b	7.8 ± 0.4 b	74.7 ± 15.7 a	n.d.	n.d.	2,785 ± 386.0 a,b	n.d.	207 ± 19.1 a
	1,500	1.3 ± 0.4 c	47.4 ± 2.5 a	0.5 ± 0.1 c	7.5 ± 0.7 b	10.3 ± 0.5 a	75.4 ± 13.1 a	n.d.	n.d.	2,650 ± 135.5 a	n.d.	235 ± 20.3 a
Critical valuesb		5 - 3	50 - 20	3.5 - 1.5	5 - 3	5 - 1	150 - 50	–	–	20 - 10	10 - 0.01	20 - 15

^a0 Fe + 50 µm ferrozine.  

^bAccording to Marschner (2012) and Gruber et al. (2013).