Split-root configuration  Element S. portulacastrum             B/B Pb/Pb B/Pb (B-K)/B (B-N)/B (B-Ca)/B Pb2+ 11.72 ± 1.67a 480.62 ± 68.66e 425.07 ± 60.72d 427.57 ± 61.08d 419.43 ± 60d 402.23 ± 57.46d Ca2+ 0.148 ± 0.021b 0.043 ± 0.0061a 0.150 ± 0.021b 0.152 ± 0.021b 0.161 ± 0.023b 0.070 ± 0.007a K+ 0.460 ± 0.065e 0.180 ± 0.025b 0.359 ± 0.051d 0.316 ± 0.048d 0.380 ± 0.054de 0.241 ± 0.034c N 27.17 ± 3.88 b 10.74 ± 1.53a 23.04 ± 3.29b 25.63 ± 3.66b 22.48 ± 3.21b 15.56 ± 2.22ab   B. juncea           Pb2+ 22.88 ± 3.26a 141.81 ± 20.25b 217.49 ± 31.07d 214.78 ± 30.68c 224.64 ± 32.09c 107.28 ± 15.32b Ca2+ 0.673 ± 0.096c 0.103 ± 0.014ab 0.591 ± 0.084c 0.547 ± 0.078c 0.569 ± 0.081c 0.118 ± 0.016ab K+ 0.563 ± 0.084f 0.087 ± 0.012 a ± 0.493 ± 0.070e 0.218 ± 0.031c 0.435 ± 0.062e 0.165 ± 0.023b N 65.95 ± 9.42e 13.51 ± 1.93a 50.671 ± 7.23d 45.70 ± 6.52cd 41.26 ± 5.89c 17.76 ± 2.5ab

Table 2: Pb, Ca2+, K+ (μg plant-1), and reduced nitrogen (mg plant-1) contents in the shoots of S. portulacastrum and B. juncea as affected by the different treatments. B: Basal medium; Pb basal medium supplied with 400 μM Pb(NO3)2; B-K; B-Ca and B-N: basal medium deprived of K+; Ca2+ or N, respectively.