Treatments B. juncea S. portulacastrum B/B 0.12 ± 0.017 (d) 0.0 6± 0.008 (b) B/Pb 0.11 ± 0.015 (d) 0.06 ± 0.008 (b) Pb/Pb 0.06 ± 0.008 (b) 0.04± 0.005 (a) (B-K)/B 0.11 ± 0.015 (d) 0.06± 0.008 (b) (B-N)/B 0.11 ± 0.015 (d) 0.06± 0.008 (b)  (B-Ca)/B 0.07 ± 0.008 (bc) 0.05± 0.007 (ab)

Table 1: Variations of the RGR values in the shoots of S. portulacastrum and B. juncea grown for 21 days in various split-root configurations. 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.