Growth Inhibition Occurs Independently of Cell Mortality in Tomato (Solanum lycopersicum) Exposed to High Cadmium Concentrations

Abstract

In order to analyze the adaptation potential of tomato shoots to a sudden increase in Cd concentration, tomato plants (Solanum lycopersicum L. var. Ailsa Craig) were exposed under controlled environmental conditions to a high dose of this heavy metal (250 microM CdCl2) in nutrient solution for 7 and 14 d. Both root and shoot growth was completely inhibited but all plants remained alive until the end of the treatment. Cell viability remained unaffected but the activity of the mitochondrial alternative pathway was stimulated by Cd stress at the expense of the cytochrome pathway. Cadmium concentration was higher in roots than in shoots and a decrease in the rate of net Cd translocation was noticed during the second week of stress. Cadmium decreased both leaf conductance (g(l)) and chlorophyll concentration. However, the effect on net CO2 assimilation remained limited and soluble sugars accumulated in leaves. Photochemical efficiency of PSII (Fv/Fm) was not affected despite a decrease in the number of reaction centers and an inhibition of electron transfer to acceptors of PSII. It is concluded that tomato shoot may sustain short term exposure to high doses of cadmium despite growth inhibition. This property implies several physiological strategies linked to both avoidance and tolerance mechanisms.

Responses to cadmium stress in two tomato genotypes differing inheavy metal accumulation

“…Our results showed higher Cd accumulation in roots than in stems and leaves (Table 2). This agreed with the results reported by Delpérée and Lutts (2008) that Cd Figure 3. TBARS in YSL189 and HZ903.…”

Comparative Study of Growth, Cadmium Accumulation and Tolerance of Three Chickpea (Cicer arietinum L.) Cultivars

“…In this study, NC2 accumulated more Cd in the root (Figure 5A), while IC8 exhibited higher Cd accumulation in its shoot ( Figure 5B). The obtained results revealed a higher accumulation of Cd in the root than in shoot ( Figure 5), which is consistent with the findings of Delpérée et al [64]. The accumulation of Cd in root and shoot of the examined chickpea cultivars was concentration-dependent.…”

Comparative analysis of Cd and Zn impacts on root distribution and morphology of Lolium perenne and Trifolium repens: implications for phytostabilization

“…6). Moreover, cell viability was not affected in 476 response to Cd treatments, as observed also by Delpérée and Lutts (2008) Cd-induced lignification was detected in the present study based on the cross-503 sections of ryegrass roots (Fig. 5).…”

“…5) which 470 contributed greatly to the observed increase of mean root diameter in the top soil 471 layer and to the drastic decrease of root depth. The reduction of root growth may 472 result from cell death, inhibition of cell division, a decrease in the rate of cell 473 elongation or different processes occurring simultaneously (Delpérée and Lutts 2008; 474 Sresty and Rao 1999). In our work, Zn treatments induced an increase in cell viability 475 in comparison to the control (Fig.…”